PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of plantmethBioMed CentralBiomed Central Web Sitesearchsubmit a manuscriptregisterthis articlePlant MethodsJournal Front Page
 
Plant Methods. 2017; 13: 30.
Published online 2017 April 19. doi:  10.1186/s13007-017-0179-1
PMCID: PMC5395794

Recent achievements obtained by chloroplast transformation

Abstract

Chloroplasts play a great role for sustained wellbeing of life on the planet. They have the power and raw materials that can be used as sophisticated biological factories. They are rich in energy as they have lots of pigment-protein complexes capable of collecting sunlight, in sugar produced by photosynthesis and in minerals imported from the plant cell. Chloroplast genome transformation offers multiple advantages over nuclear genome which among others, include: integration of the transgene via homologus recombination that enables to eliminate gene silencing and position effect, higher level of transgene expression resulting into higher accumulations of foreign proteins, and significant reduction in environmental dispersion of the transgene due to maternal inheritance which helps to minimize the major critic of plant genetic engineering. Chloroplast genetic engineering has made fruit full progresses in the development of plants resistance to various stresses, phytoremediation of toxic metals, and production of vaccine antigens, biopharmaceuticals, biofuels, biomaterials and industrial enzymes. Although successful results have been achieved, there are still difficulties impeding full potential exploitation and expansion of chloroplast transformation technology to economical plants. These include, lack of species specific regulatory sequences, problem of selection and shoot regeneration, and massive expression of foreign genes resulting in phenotypic alterations of transplastomic plants. The aim of this review is to critically recapitulate the latest development of chloroplast transformation with special focus on the different traits of economic interest.

Keywords: Chloroplast transformation, Novel traits, Homologus recombination, Transgene, Regulatory sequences

Background

World population is expected to rise to 9.2 billion in 2050. In order to feed the rising population food production has to grow in parallel. The problem is that arable land is exploited to its potential (High Level Expert Forum, FAO, October 2009; http://www.fao.org). Advancement in agricultural biotechnology particularly plant genetic engineering is believed to boost crop productivity. Due to enormous rewards crucial traits have been engineered via chloroplast genome instead of nuclear genome. It is amazing that more than 120 genes from various sources have been well integrated and expressed via the chloroplast genome for various applications. Aims of these applications include, developing crops with high levels of resistance to insects, bacterial, fungal and viral diseases, different types of herbicides, drought, salt and cold tolerance, cytoplasmic male sterility, metabolic engineering, phytoremediation of toxic metals and production of many vaccine antigens, biopharmaceuticals, industrial enzymes and biofuels [15].

Chloroplasts originated from endosymbiosis around 1.5 billion years ago, when a cyanobacterial cell was engulfed by heterotrophic eukaryote [6, 15]. Chloroplast organelle of plants and algal cells evolved from photosynthetic bacteria living inside the primitive ancestors of plant cells [7, 8]. Chloroplast gene products are not only homologus to the present-day cyanobacteria but the arrangement and expression of genes also reflect the prokaryotic ancestry of chloroplasts. They possess multiple copies of a small circular genome with 100–250 genes and their genome size varies between species, ranging from 107 kb (Cathaya argyrophylla) to 218 kb (Pelargonium) and maternally inherited in angiosperm plants [5]. There is a strong believe that the action of gene transfer and genome streamlining resulted into a drastic shrinkage of the genome of cyanobacterial endosymbiont where thousands of genes disappeared and were either transferred to nucleus or lost. Consequently, modern-day chloroplast genomes of photosynthetic eukaryotes are much reduced [9, 10].

The high ploidy number of the plastid genome and compartmentalization of proteins allow high levels of foreign protein expression from 5 to 40% total soluble protein [11] and up to 70% total soluble protein in Tobacco [2, 3, 12]. Moreover, nuclear encoded proteins are also accumulated at high level inside the chloroplast, although the ploidy level is not as high as chloroplast encoded proteins. That is why recent advancement in plant biotechnology has proved the use of chloroplasts as excellent ideal host for conferring agronomic traits and production of biopharmaceuticals, biomaterials and industrial enzymes [13]. Chloroplast genetic engineering has enormous advantages over nuclear transformation as well explained in Table 1 [1, 5, 1425].

Table 1
Comparative advantages of chloroplast genome over nuclear genome

Chloroplast transformation

Multistep processes are involved to achieve chloroplast transformation. Species specific or heterologous chloroplast transformation vectors are developed in a manner that flanks the foreign genes and insert them through homologous recombination at predetermined and precise location in the plastome [26]. When the foreign DNA is delivered into plasmids, initially only a few copies of the plastome are transformed resulting in-to heteroplasmic state. Then, through sub-culturing the bombarded explants in vitro under selection all copies of the plastome contains the transgene leading to the state of homoplsamy, where all the plastomes of the chloroplasts present in the cell are transformed (Fig. 1). Generally, three key conditions have to be full-filled to achieve plastid transformation: (1) a robust method of DNA delivery into the chloroplast, (2) the presence of active homologous recombination machinery in the plastid, and (3) the availability of highly efficient selection and regeneration protocols for transplastomic cells [11, 27].

Fig. 1
Diagrammatic representation of the processes for chloroplast genome transformation. a Basic design of a typical vector for transforming the plastid genome. Both the expression cassette and the selection cassette are placed between the two plastid regions. ...

Transformation is highly efficient when there is complete homology of plastid DNA flanking sequences. For successful transformation, it is critical to identify promoters, 5′-UTRs, 3′-UTRs and insertion sites as indicated in Table 2. Complete chloroplast genome sequences are essential for integration of the transgene at optimal site via homologus recombination and to identify endogenous regulatory sequences for optimal transgene expression [28, 29].

Table 2
Commonly used promoters, un-translated regions and insertion sites for chloroplast transformation as avowed in [25, 117]

Plastid transformation was first achieved in unicellular algae called Chlamydomonas reindhartii [30]. Tobacco was the first higher plant in which chloroplast transformation was successfully performed [31, 32]. Similarly, a protocol for plastid transformation of an elite rapeseed cultivar (Brassica napus L.) has been developed [33].

Traits of interest for chloroplast transformation

Conferring agronomic traits

Researchers have successfully engineered different genes on chloroplasts to confer agronomic traits of interest. For instance simultaneous expression of protease inhibitors and chitinase have been employed to develop multiple biotic and abiotic stresses resistant plants, particularly tobacco [34]. Economical agronomic traits, such as herbicide resistance, insect resistance and tolerance to drought and salt, have already been engineered via the plastid genome [35]. The dominant trait that attracted the most attention for plastid transformation has been herbicide tolerance [11, 3638]. The production of plants resistant to high level of glyphosate was achieved through biolistic transformation of plastids by introduction of a mutated herbicide-tolerant gene coding for EPSP synthase [11] (Table 3).

Table 3
Agronomic traits engineered via chloroplast genome

Production of vaccine antigens and biopharmaceuticals

It is believed that more than 90% of the global population cannot afford insulin, a drug needed to treat the global diabetes epidemic [5]. The high cost of protein drugs is due to their production in prohibitively expensive fermentation systems, prohibitively expensive purification from host proteins, the need for refrigerated storage and transport, and the short shelf-life of the final product [66, 67]. Protein drugs made by plant chloroplasts overcome most of these challenges as they do not require such expensive production process and can be stored without losing efficacy [68, 69] As listed in Table Table44 numerous vaccine antigens and biopharmaceuticals have been engineered via chloroplast genome of higher plants.

Table 4
Vaccine antigens and biopharmaceuticals engineered via chloroplast genome of higher plants

Among plant plastids, tobacco plastid has been engineered to express the E7 HPV type 16 protein, which is an attractive candidate for anticancer vaccine development [83]. The main factor why plant plastids are chosen as better bioreactors is due to the ability of plants to correctly carry out post-translation modifications such as phosphorylation, amidation, proper folding, formation of disulfide bonds and the assembly of complex multi-subunit proteins. Microorganisms are also used for large-scale industrial applications of recombinant protein production, but cannot carryout post-translational modifications [35]. The hyper-expression of vaccine antigens or therapeutic proteins in transgenic chloroplasts (leaves) or chromoplasts (fruits/roots) and antibiotic-free selection systems available in plastid transformation systems became successful in the oral delivery of vaccine antigens against cholera, tetanus, anthrax, plague, and canine parvovirus [17, 28, 69, 84]. Although higher level protein production is vital of chloroplast, too much expression of foreign proteins in chloroplasts is causing toxicity on host plant. Temporary immersion bioreactors (TIBs) using Alka Burst technology has produced leafy biomass that expressed OspA at levels of up to 7.6% total soluble protein to give a maximum yield of OspA (about 108 mg/L). These results show that TIBs offer an alternative method for the production of transplastomic biomass proteins, which are non-toxic for plants and particularly useful when absolute gene dispersion control is required [85] From a single plant Chlanydomonas reinhadtii various recombinant therapeutic proteins have been produced (Table (Table55).

Table 5
Recombinant therapeutic proteins produced in the chloroplast of Chlanydomonas reinhadtii

Phytoremediation

It is strongly believed that phytoremediation is a safe and cost-effective system for cleaning up contaminated environments using plants. Organomercurial compounds are the most toxic forms of mercury and chloroplast genome is a primary target of mercury damage in plants. It is, thus, an ideal site to engineer resistance and detoxification of organomercurials and metallic mercury [93]. Chloroplast genetic engineering of plants for synthesis of metal chelators has improved the capability of plants for metal uptake [94, 95].

Two bacterial genes encoding two enzymes, mercuric ion reductase (merA) and organomercurial lyase (merB), were expressed as an operon in transgenic tobacco chloroplasts. This demonstrated accumulate of mercury in roots to levels surpassing the concentration in soil, up to 200 μg/g, without any detrimental effect and could accumulate 100-fold more mercury in leaves than untransformed plants [96]. Phytoremediation of toxic mercury was achieved by engineering of tobacco chloroplast with metallothionein enzyme [53].

Production of industrial enzymes and biomaterials

Chloroplast genome has been successfully engineered to produce important enzymes and biomaterials. Despite the diversion of major metabolic intermediate, metabolic engineering using chloroplast genomes produced the highest level of the poly (p-hydroxybenzoic acid (pHBA) polymer (25% dry weight) in normal healthy plants [97]. Optimized genetic construct for plastid transformation of tobacco (Nicotiana tobacum) for the production of the renewable biodegradable plastic poly hydroxy butyrate (PHB) was designed using an operon extension strategy [98]. Lots of efforts have been made to produce PHB in different systems, but to date, the highest levels of PHB have been achieved in plastids. This was due to the high flux of the PHB pathway substrate acetyl-CoA through this organelle during fatty acid biosynthesis [99, 100] Typical examples of biomaterials and enzymes that have been engineered via chloroplast genome of Tobacco are mentioned in (Table (Table66).

Table 6
Biomaterials and enzymes engineered via chloroplast genome of Tobacco

Production of biofuels

The most important and first requirement for lingo-cellulosic biofuels production is to develop an efficient enzyme production system for economical and rapid biomass depolymerization. High levels of expression and compartmentalization of toxic proteins within chloroplasts enables to protect transgenic plants from pleiotropic effects, making chloroplast an ideal bioreactor for industrial enzyme production [25]. Although it was possible to have single biofuels enzymes expressed whole biomass hydrolysis was not effective because of the requirement of more number of enzymes [94, 95]. The development of chloroplast derived cocktails of enzymes for production of fermentable sugars from different ligno-cellulosic biomass become major fresh breakthrough in biofuels research. Different enzymes from bacteria or fungi, namely β-1,4-endoglucanase, Beta glucosidase, Swollenin, esterase, cutinase, endoglucanases, exoglucanase, pectate lyases, xylanase, lipase, acetyl, Acetyl xylan esterase and xylan were expressed in tobacco chloroplasts for production of fermentable sugars [107111].

Endoglucanase Ce19A, β-glucosidase Bg11C, Exoglucanase Ce16B and xyloglucanase Xeg74 from Trichoderma fusca were highly active and hydrolyzed their synthetic test substrates in a dose dependent manner. The cocktail of these enzymes triggered efficient sugar release from straw [107]. Treatment of cotton fiber with chloroplast derived cutinase showed enlarged segments and the intertwined inner fibers were irreversibly unwound due to expansion activity of cutinase. Chloroplast derived cutinase showed esterase and lipase activity [110]. Β-1,4-endoglucanase from Pyrococcus horikoshii which drives EPGh from chloroplast was able to recover from dry leaves and digested carboxylmethyl cellulose(CMC) substrate [56]. β-Mannanase enzyme from Trichoderma reesei showed sixfold to sevenfold higher enzyme activity than E. coli. β-Mannanase enzyme cocktail with chloroplast derived mannanse yielded 20% more glucose equivalents from pinewood than the cocktail without mannanase [111]. Catalytic activity of chloroplast produced Xylanase was detected with birch wood xylan as substrate [112]. Chloroplast enzymes (Endoglucanase, Swollenin, Acetyl xylan esterase, Xylanase enzymes originated from T. reesei, Endoglucanase exoglucanase from C. thermocellum, Lipase from M. tuberclosis, Cutinase and Pectate lyase A from F. solani) showed wider pH and higher temperature stability than enzymes expressed in E. coli. Chloroplast derived crude extract enzyme cocktails yielded more than 36-fold glucose from citrus peel, filter paper or pine wood than commercial cocktails [113].

Conclusion and prospects

Chloroplast genome has become the target of many plant genetic transformation efforts due to its enormous advantages over nuclear genome of the plant. The nuclear transgenic approach is incapable to develop products when higher-level transgene expression and multigene engineering is a requirement. Chloroplast transformation is expected to offer unique advantages in the advancement of different biotechnological applications; including, phytoremediation, production of industrial enzymes, biofuels, biomaterials, molecular farming for the production of antibiotics, vaccines, biopharmaceuticals and conferring agronomic traits. Chloroplast transformation has been achieved only to tobacco, lettuce, Arabidopsis, tomato, carrot, oilseed rape, potato, cabbage, cotton, petunia, soybean, sugarcane, sugar beet, rice, eggplant, cauliflower and poplar [114].

Although successful progresses have been made, full potential exploitation of chloroplast technology requires addressing critical challenges. These include: recalcitrant nature of cereal species to existing regeneration protocols is daunting so developing efficient shoot regeneration system is very critical [115], optimizing the level of expression as massive expression of foreign proteins is resulting in phenotypic alterations of transplastomic plants [116], lack of appropriate tissue specific regulatory sequences [117, 118], problem of gene expression in non-green plastids [119], unintended homologus recombination that hinder efficient recovery of transplastomic transformants containing the desired transgene [120], degradation of foreign proteins is a limiting factor for accumulation of foreign proteins in transgenic chloroplasts [50, 121, 122] low frequency transgene dispersion might occur due to occasionally parental/biparental transmission of plastids and via transgene transfer to nuclear genome [115]. To ease public concern and increase public acceptance production of marker free transplastomic plants is also very important. As chloroplast genome is capable of expressing more than 120 foreign genes originated from different organisms (bacteria, animals, viruses, fungi and humans), addressing the above barriers will make chloroplast genome very attractive site for various biotechnological applications with incredible impact on human life.

Authors’ contributions

MA has prepared the manuscript and DB, TF read and approved the review for publication. All authors read and approved the final manuscript.

Acknowledgements

Not applicable.

Competing interests

The authors declare that they have no any competing interests.

Consent for publication

Figure 1 directly reproduced from Ref.[113] with permission from Author Ahmad et al. (2016b).

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Abbreviations

UTR
un-translated region
TLP
total leaf protein
TSP
total soluble protein
TCP
total cell protein

Contributor Information

Muhamed Adem, te.ude.uaa@meda.demahum.

Dereje Beyene, te.ude.uaa@eneyeb.ejered.

Tileye Feyissa, moc.oohay@assiyef_eyelit.

References

1. Bock R. Plastid biotechnology: prospects for herbicide and insect resistance, metabolic engineering, and molecular farming. Curr Opin Biotechnol. 2007;18:100–106. doi: 10.1016/j.copbio.2006.12.001. [PubMed] [Cross Ref]
2. Daniell H, Singh ND, Mason H, Streatfield SJ. Plant-made vaccine antigens and biopharmaceuticals. Trends Plant Sci. 2009;14:669–679. doi: 10.1016/j.tplants.2009.09.009. [PMC free article] [PubMed] [Cross Ref]
3. Bock R, Warzecha H. Solar-powered factories for new vaccines and antibiotics. Trends Biotechnol. 2010;28:246–252. doi: 10.1016/j.tibtech.2010.01.006. [PubMed] [Cross Ref]
4. Clarke JL, Daniell H. Plastid biotechnology for crop production: present status and future perspectives. Plant Mol Biol. 2011 [PMC free article] [PubMed]
5. Daniell H, Choun-S L, Ming Y, Wan- JC. Chloroplast genomes: diversity, evolution, and applications in genetic engineering. Genome Biol. 2016;17:134. doi: 10.1186/s13059-016-1004-2. [PMC free article] [PubMed] [Cross Ref]
6. Ahmad N, Burgess SJ, Nielsen BL. Editorial: advances in plastid biology and its applications. Front Plant Sci. 2016;7:1396. [PMC free article] [PubMed]
7. Maul JE, Lilly JW, Cui L, Depamphilis CW, Miller W, Harris EH, et al. The Chlamydomonas reinhardtii plastid chromosome: islands of genes in a sea of repeats. Plant Cell. 2002;14:2659–2679. doi: 10.1105/tpc.006155. [PubMed] [Cross Ref]
8. Stephen D. Green genes—DNA in (and out of) chloroplasts sciences and plants. 2013. http://www-saps.plantsci.cam.ac.uk. Accessed 14 Apr 2017.
9. Bock R, Timmis JN. Reconstructing evolution: gene transfer from plastids to the nucleus. BioEssays. 2008;30:556–566. doi: 10.1002/bies.20761. [PubMed] [Cross Ref]
10. Qiu H, Price DC, Weber APM, Facchinelli F, Yoon HS, Bhattacharya D. Assessing the bacterial contribution to the plastid proteome. Trends Plant Sci. 2013;18:680–687. doi: 10.1016/j.tplants.2013.09.007. [PubMed] [Cross Ref]
11. Roudsari MF, Salmanian AH, Mousavi A, Sohi HH, Jafari M. Regeneration of glyphosate-tolerant Nicotiana tabacum after plastid transformation with a mutated variant of bacterial aroA gene. Iran J Biotechnol. 2009;7:247–253.
12. Bock R. Engineering plastid genomes: methods, tools, and applications in basic research and biotechnology. Annu Rev Plant Biol. 2015;66:31–33. doi: 10.1146/annurev-arplant-050213-040212. [PubMed] [Cross Ref]
13. Beeramganti N, Beeramganti H,Subramanyam K, Rajasekhar P. Chloroplast expression vector system & its transformation. Int J Sci Technol. 2012; 2(4).
14. Staub JM, Garcia B, Graves J, Hajdukiewicz PTJ, Hunter P, Nehra N, et al. High-yield production of a human therapeutic protein in tobacco chloroplasts. Nat Biotechnol. 2000;18:333–338. doi: 10.1038/73796. [PubMed] [Cross Ref]
15. Maliga P. Progress towards commercialization of plastid transformation technology. Trends Biotechnol. 2003;21(1):20–28. doi: 10.1016/S0167-7799(02)00007-0. [PubMed] [Cross Ref]
16. Maliga P. Plastid transformation in higher plants. Annu Rev Plant Biol. 2004;55:289–313. doi: 10.1146/annurev.arplant.55.031903.141633. [PubMed] [Cross Ref]
17. Daniell H, Chebolu S, Kumar S, Singleton M, Falconer R. Chloroplast-derived vaccine antigens and other therapeutic proteins. Vaccine. 2005;23:1779–1783. doi: 10.1016/j.vaccine.2004.11.004. [PubMed] [Cross Ref]
18. Ruhlman T, Sb Lee, Jansen RK, Hostetler JB, Tallon LJ, Town CD, et al. Complete plastid genome sequence of Daucus carota: implications for biotechnology and phylogeny of angiosperms. BMC Genom. 2006;7:222. doi: 10.1186/1471-2164-7-222. [PMC free article] [PubMed] [Cross Ref]
19. Moeller L, Wang K. Engineering with precision: tools for the new generation of transgenic crops. Bioscience. 2008;58:391–401. doi: 10.1641/B580506. [Cross Ref]
20. Hasunuma T, Miyazawa S, Yoshimura S, Shinzaki Y, Tomizawa KI, Shindo K, et al. Biosynthesis of astaxanthin in tobacco leaves by transplastomic engineering. Plant J. 2008;55:857–868. doi: 10.1111/j.1365-313X.2008.03559.x. [PubMed] [Cross Ref]
21. Cardi T, Lenzi P, Maliga P. Chloroplasts as expression platform for plant-produced vaccines. Expert Rev Vaccines. 2010;9:893–911. doi: 10.1586/erv.10.78. [PubMed] [Cross Ref]
22. Meyers B, Zaltsman A, Lacroix B, Kozlovsky SV, Krichevsky A. Nuclear and plastid genetic engineering of plants: comparison of opportunities and challenges. Biotechnol Adv. 2010;6:747–756. doi: 10.1016/j.biotechadv.2010.05.022. [PubMed] [Cross Ref]
23. Obembe OO, Popoola JO, Leelavathi S, Reddy VS. Advances in plant molecular farming. Biotechnol Adv. 2010 [PubMed]
24. Day A, Michel GC. The chloroplast transformation toolbox: selectable markers and marker removal. Plant Biotechnol J. 2011;9:540–553. doi: 10.1111/j.1467-7652.2011.00604.x. [PubMed] [Cross Ref]
25. Jin S, Daniell H. Engineered chloroplast genome just got smarter. Trends Plant Sci. 2015;20(10):622–640. doi: 10.1016/j.tplants.2015.07.004. [PMC free article] [PubMed] [Cross Ref]
26. Khan MS. Plastid genome engineering in plants: present status and future trends. Mol Plant Breed. 2012;3(8):91–102.
27. Doetsch NA, Favreau MR, Kuscuoglu N, Thompson MD, Hallick RB. Chloroplast transformation in Euglena gracilis: splicing of a group II twin intron transcribed from a transgenic psbK operon. Curr Genet. 2011;39:49–60. doi: 10.1007/s002940000174. [PubMed] [Cross Ref]
28. Grevich JJ, Daniell H. Chloroplast genetic engineering: recent advances and future perspectives. Crit Rev Plant Sci. 2015;24:83–107. doi: 10.1080/07352680590935387. [Cross Ref]
29. Ruhlman T, Verma D, Samson N, Daniell H. The role of heterologous chloroplast sequence elements in transgene integration and expression. Plant Physiol. 2010;152:2088–2104. doi: 10.1104/pp.109.152017. [PubMed] [Cross Ref]
30. Boynton JE, Gillham NW, Harris EH, Hosler JP, Johnson AM, Jones AR, et al. Chloroplast transformation in Chlamydomonas with high velocity microprojectiles. Sciences. 1998;240:1534–1538. doi: 10.1126/science.2897716. [PubMed] [Cross Ref]
31. Svab Z, Hajdukiewicz P, Maliga P. Stable transformation of plastids in higher plants. Proc Natl Acad Sci. 1990;87:8526–8530. doi: 10.1073/pnas.87.21.8526. [PubMed] [Cross Ref]
32. Jabeen R, Khan MS, Zafar Y, Anjum T. Codon optimization of cry1Ab gene for hyper expression in plant organelles. Mol Biol Rep. 2010;37:1011–1017. doi: 10.1007/s11033-009-9802-1. [PubMed] [Cross Ref]
33. Cheng L, Li HP, Qu B, Huang T, Tu JX, Fu TD, et al. Chloroplast transformation of rapeseed (Brassica napus L.) by particle bombardment of cotyledons. Plant Cell Rep. 2010;29:371–378. doi: 10.1007/s00299-010-0828-6. [PubMed] [Cross Ref]
34. Chen PJ, Senthilkumar R, Jane WN, He Y, Tian Z, Yeh KW. Transplastomic Nicotiana benthamiana plants expressing multiple defence genes encoding protease inhibitors and chitinase display broad-spectrum resistance against insects, pathogens and abiotic stresses. Plant Biotechnol J. 2014;12:503–515. doi: 10.1111/pbi.12157. [PubMed] [Cross Ref]
35. Jana Ř. Potential of chloroplast genome in plant breeding. Czech J Genet Plant Breed. 2010;46(3):103–113.
36. Kang TJ, Loc NH, Jang MO, Jang YS, Kim YS, Seo JE, et al. Expression of the B subunit of E. coli heat-labile enterotoxin in the chloroplasts of plants and its characterization. Transgenic Res. 2003;12:683–691. doi: 10.1023/B:TRAG.0000005114.23991.bc. [PubMed] [Cross Ref]
37. Daniell H, Datta R, Varma S, Gray S, Lee SB. Containment of herbicide resistance through genetic engineering of the chloroplast genome. Nat Biotechnol. 1998;16:345–348. doi: 10.1038/nbt0498-345. [PubMed] [Cross Ref]
38. Haghani K, Salmanian AH, Ranjbar B, Zakikhan K, Khajeh K. Comparative studies of wild type E. coli 5-enolpyruvylshikimate 3-phosphate synthase with three lyphosate insensitive mutated forms, activity, stability and structural characterization. Biochim Biophys Acta. 2008;1784:1167–1175. doi: 10.1016/j.bbapap.2007.07.021. [PubMed] [Cross Ref]
39. Fouad WM, Altpeter F. Transplastomic expression of bacterial l-aspartate-alpha-decarboxylase enhances photosynthesis and biomass production in response to high temperature stress. Transgenic Res. 2009;18:707–718. doi: 10.1007/s11248-009-9258-z. [PubMed] [Cross Ref]
40. Oey M, Lohse M, Scharff LB, Kreikemeyer B, Bock R. Plastid production of protein antibiotics against pneumonia via a new strategy for high level expression of antimicrobial proteins. Proc Natl Acad Sci USA. 2009;106:6579–6584. doi: 10.1073/pnas.0813146106. [PubMed] [Cross Ref]
41. Dufourmantel N, Dubald M, Matringe M, Canard H, Garcon F, Job C, et al. Generation and characterization of soybean and marker-free tobacco plastid transformants over-expressing a bacterial 4-hydroxyphenylpyruvate dioxygenase which provides strong herbicide tolerance. Plant Biotechnol J. 2007;5:118–133. doi: 10.1111/j.1467-7652.2006.00226.x. [PubMed] [Cross Ref]
42. Kumar S, Dhingra A, Daniell H. Plastid-expressed betaine aldehyde dehydrogenase gene in carrot cultured cells, roots, and leaves confers enhanced salt tolerance. Plant Physiol. 2004;136:2843–2854. doi: 10.1104/pp.104.045187. [PubMed] [Cross Ref]
43. Wurbs D, Ruf S, Bock R. Contained metabolic engineering in tomatoes by expression of carotenoid biosynthesis genes from the plastid genome. Plant J. 2007;49:276–288. doi: 10.1111/j.1365-313X.2006.02960.x. [PubMed] [Cross Ref]
44. Lu Y, Rijzaani H, Karcher D, Ruf S, Bock R. Efficient metabolic pathway engineering in transgenic tobacco and tomato plastids with synthetic multigene operons. Proc Natl Acad Sci USA. 2013;110:E623–E632. doi: 10.1073/pnas.1216898110. [PubMed] [Cross Ref]
45. Ye GN, Hajdukiewicz PT, Broyles D, Rodriguez D, Xu CW, Nehra N, Staub JM. Plastid-expressed 5-enolpyruvylshikimate-3-phosphate synthase genes provide high level glyphosate tolerance in tobacco. Plant J. 2001;25:261–270. doi: 10.1046/j.1365-313x.2001.00958.x. [PubMed] [Cross Ref]
46. Lutz KA, Knapp JE, Maliga P. Expression of bar in the plastid genome confers herbicide resistance. Plant Physiol. 2001;125:1585–1590. doi: 10.1104/pp.125.4.1585. [PubMed] [Cross Ref]
47. Ruiz ON, Daniell H. Engineering cytoplasmic male sterility via the chloroplast genome by expression of beta-ketothiolase. Plant Physiol. 2005;138:1232–1246. doi: 10.1104/pp.104.057729. [PubMed] [Cross Ref]
48. Jin S, Daniell H. Expression of gamma-tocopherol methyltransferase in chloroplasts results in massive proliferation of the inner envelope membrane and decreases susceptibility to salt and metal-induced oxidative stresses by reducing reactive oxygen species. Plant Biotechnol J. 2014;12:1274–1285. doi: 10.1111/pbi.12224. [PMC free article] [PubMed] [Cross Ref]
49. Dhingra A, Portis AR, Jr, Daniell H. Enhanced translation of a chloroplast expressed RbcS gene restores small subunit levels and photosynthesis in nuclear RbcS antisense plants. Proc Natl Acad Sci USA. 2004;101:6315–6320. doi: 10.1073/pnas.0400981101. [PubMed] [Cross Ref]
50. Jin S, Kanagaraj A, Verma D, Lange T, Daniell H. Release of hormones from conjugates: chloroplast expression of beta-glucosidase results in elevated phytohormone levels associated with significant increase in biomass and protection from aphids or whiteflies conferred by sucrose esters. Plant Physiol. 2011;155:222–235. doi: 10.1104/pp.110.160754. [PubMed] [Cross Ref]
51. Viitanen PV, Devine AL, Khan MS, Deuel DL, Van Dyk DE, Daniell H. Metabolic engineering of the chloroplast genome using the Echerichia coli ubiC gene reveals that chorismate is a readily abundant plant precursor for p-hydroxybenzoic acid biosynthesis. Plant Physiol. 2004;136:4048–4060. doi: 10.1104/pp.104.050054. [PubMed] [Cross Ref]
52. Yabuta Y, Tanaka H, Yoshimura S, Suzuki A, Tamoi M, Maruta T, Shigeoka S. Improvement of vitamin E quality and quantity in tobacco and lettuce by chloroplast genetic engineering. Transgenic Res. 2013;22:391–402. doi: 10.1007/s11248-012-9656-5. [PubMed] [Cross Ref]
53. Agrawal P, Verma D, Daniell H. Expression of Trichoderma reesei betamannanase in tobacco chloroplasts and its utilization in lignocellulosicwoody biomass hydrolysis. PLoS ONE. 2011;6:e29302. doi: 10.1371/journal.pone.0029302. [PMC free article] [PubMed] [Cross Ref]
54. Verma D, Jin S, Kanagaraj A, Singh ND, Daniel J, Kolattukudy PE, et al. Expression of fungal cutinase and swollenin in tobacco chloroplasts reveals novel enzyme functions and/or substrates. PLoS ONE. 2013;8:e57187. doi: 10.1371/journal.pone.0057187. [PMC free article] [PubMed] [Cross Ref]
55. Harada H, Maoka T, Osawa A, Hattan J, Kanamoto H, Shindo K, et al. Construction of transplastomic lettuce dominantly producing astaxanthin fatty acid esters and detailed chemical analysis of generated carotenoids. Transgenic Res. 2014;23:303–315. doi: 10.1007/s11248-013-9750-3. [PubMed] [Cross Ref]
56. Wang YP, Wei ZY, Zhang YY, Lin CJ, Zhong XF, Wang YL, et al. Chloroplast expressed MSI-99 in tobacco improves disease resistance and displays inhibitory effect against rice blast fungus. Int J Mol Sci. 2015;16:4628–4641. doi: 10.3390/ijms16034628. [PMC free article] [PubMed] [Cross Ref]
57. Dufourmantel N, Tissot G, Goutorbe F, Garcon F, Muhr C, Jansens S, et al. Generation and analysis of soybean plastid transformants expressing Bacillus thuringiensis Cry1Ab protoxin. Plant Mol Biol. 2005;58:659–668. doi: 10.1007/s11103-005-7405-3. [PubMed] [Cross Ref]
58. De Cosa B, Moar W, Lee SB, Miller M, Daniell H. Over expression of the Bt cry2Aa2 operon in chloroplasts leads to formation of insecticidal crystals. Nat Biotechnol. 2001;19:71–74. doi: 10.1038/83559. [PMC free article] [PubMed] [Cross Ref]
59. DeGray G, Rajasekaran K, Smith F, Sanford J, Daniell H. Expression of an antimicrobial peptide via the chloroplast genome to control phytopathogenic bacteria and fungi. Plant Physiol. 2001;127:852–862. doi: 10.1104/pp.010233. [PubMed] [Cross Ref]
60. Chakrabarti SK, Lutz KA, Lertwiriyawong B, Svab Z, Maliga P. Expression of the cry9Aa2 B.t. gene in tobacco chloroplasts confers resistance to potato tuber moth. Transgenic Res. 2006;15:481–488. doi: 10.1007/s11248-006-0018-z. [PubMed] [Cross Ref]
61. Ruhlman TA, Rajasekaran K, Cary JW. Expression of chloroperoxidase from Pseudomonas pyrrocinia in tobacco plastids for fungal resistance. Plant Sci. 2014;228:98–106. doi: 10.1016/j.plantsci.2014.02.008. [PubMed] [Cross Ref]
62. Verma D, Kanagaraj A, Jin SX, Singh ND, Kolattukudy PE, Daniell H. Chloroplast-derived enzyme cocktails hydrolyse lignocellulosic biomass and release fermentable sugars. Plant Biotechnol J. 2010;8:332–350. doi: 10.1111/j.1467-7652.2009.00486.x. [PMC free article] [PubMed] [Cross Ref]
63. Lee SB, Li B, Jin S, Daniell H. Expression and characterization of antimicrobial peptides Retrocyclin-101 and Protegrin-1 in chloroplasts to control viral and bacterial infections. Plant Biotechnol J. 2011;9:100–115. doi: 10.1111/j.1467-7652.2010.00538.x. [PMC free article] [PubMed] [Cross Ref]
64. Jin S, Zhang X, Daniell H. Pinellia ternata agglutinin expression in chloroplasts confers broad spectrum resistance against aphid, whitefly, Lepidopteran insects, bacterial and viral pathogens. Plant Biotechnol J. 2012;10:313–327. doi: 10.1111/j.1467-7652.2011.00663.x. [PMC free article] [PubMed] [Cross Ref]
65. Grabowski H, Cockburn I, Long G. The market for follow-on biologics: how will it evolve? Health Aff. 2006;25:1291–1301. doi: 10.1377/hlthaff.25.5.1291. [PubMed] [Cross Ref]
66. Spök A, Karner S, Stein AJ, Rodríguez-C E. Plant molecular farming; opportunities and challenges. JRC Scientific and Technical Reports. 2008.
67. Farran I, McCarthy-S I, Río-M F, Mansilla C, Lasarte JJ. Mingo-CM. The vaccine adjuvant extra domain A from fibronectin retains its proinflammatory properties when expressed in tobacco chloroplasts. Planta. 2010;231:977–990. doi: 10.1007/s00425-010-1102-4. [PubMed] [Cross Ref]
68. Holtz BR, Berquist BR, Bennett LD, Kommineni VJ, Munigunti RK, White EL. Commercial-scale biotherapeutics manufacturing facility for plant made pharmaceuticals. Plant Biotechnol J. 2015;13:1180–1190. doi: 10.1111/pbi.12469. [PubMed] [Cross Ref]
69. Rosales-Mendoza S, Soria-Guerra RE, Moreno-Fierros L, Alpuche-Solís AG, Martínez-González L, Korban SS. Expression of an immunogenic F1-V fusion protein in lettuce as a plant-based vaccine against plague. Planta. 2010;232:409–416. doi: 10.1007/s00425-010-1176-z. [PubMed] [Cross Ref]
70. Morgenfeld M, Lentz E, Segretin ME, Alfano EF, Bravo-Almonacid F. Translational fusion and redirection to thylakoid lumen as strategies to enhance accumulation of human papilloma virus E7 antigen in tobacco chloroplasts. Mol Biotechnol. 2014;56:1021–1031. doi: 10.1007/s12033-014-9781-x. [PubMed] [Cross Ref]
71. Chan H-T, Xiao Y, Weldon WC, Oberste SM, Chumakov K, Daniell H. Cold chain and virus free chloroplast-made booster vaccine to confer immunity against different polio virus serotypes. Plant Biotechnol J. 2016 [PMC free article] [PubMed]
72. Lakshmi PS, Verma D, Yang X, Lloyd B, Daniell H. Low cost tuberculosis vaccine antigens in capsules: expression in chloroplasts, bio-encapsulation, stability and functional evaluation in vitro. PLoS ONE. 2013;8:54708. doi: 10.1371/journal.pone.0054708. [PMC free article] [PubMed] [Cross Ref]
73. Gorantala J, Grover S, Rahi A, Chaudhary P, Rajwanshi R, Sarin NB, et al. Generation of protective immune response against anthrax by oral immunization with protective antigen plant-based vaccine. J Biotechnol. 2014;176:1–10. doi: 10.1016/j.jbiotec.2014.01.033. [PubMed] [Cross Ref]
74. Gottschamel J, Lössl A, Ruf S, Wang Y, Skaugen M, Bock R, et al. Production of dengue virus envelope protein domain III-based antigens in tobacco chloroplasts using inducible and constitutive expression systems. Plant Mol Biol. 2016;91:497–512. doi: 10.1007/s11103-016-0484-5. [PubMed] [Cross Ref]
75. Oey M, Lohse M, Kreikemeyer B, Bock R. Exhaustion of the chloroplast protein synthesis capacity by massive expression of a highly stable protein antibiotic. Plant J. 2009;57:436–445. doi: 10.1111/j.1365-313X.2008.03702.x. [PubMed] [Cross Ref]
76. Su J, Sherman A, Doerfler PA, Byrne BJ, Herzog RW, Daniell H. Oral delivery of Acid Alpha Glucosidase epitopes expressed in plant chloroplasts suppresses antibody formation in treatment of Pompe mice. Plant Biotechnol J. 2015;13:1023–1032. doi: 10.1111/pbi.12413. [PMC free article] [PubMed] [Cross Ref]
77. Lim S, Ashida H, Watanabe R, Inai K, Kim Y-S, Mukougawa K, et al. Production of biologically active human thioredoxin 1 protein in lettuce chloroplasts. Plant Mol Biol. 2011;76:335–344. doi: 10.1007/s11103-011-9745-5. [PubMed] [Cross Ref]
78. Ruiz O. Optimization of codon composition and regulatory elements for expression of the human IGF-1 in transgenic chloroplasts. MS thesis, University of Florida. 2002.
79. Oey M, Lohse M, Scharff LB, Kreikemeyer B, Bock R. Plastid production of protein antibiotics against pneumonia via a new strategy for high-level expression of antimicrobial proteins. Proc Natl Acad Sci USA. 2009;106:6579–6584. doi: 10.1073/pnas.0813146106. [PubMed] [Cross Ref]
80. Arlen PA, Falconer R, Cherukumilli S, Cole A, Cole AM, Oishi KK, et al. Field production and functional evaluation of chloroplast derived interferon-α2b. Plant Biotechnol J. 2007;5:511–525. doi: 10.1111/j.1467-7652.2007.00258.x. [PMC free article] [PubMed] [Cross Ref]
81. Wang YP, Wei ZY, Zhong XF, Lin CJ, Cai YH, Ma J, et al. Stable expression of basic fibroblast growth factor in chloroplasts of tobacco. Int J Mol Sci. 2016;17:9–18.
82. Morgenfeld M, Segretin ME, Wirth S, Lentz E, Zelada A, Mentaberry A, et al. Potato virus X coat protein fusion to human papilloma virus 16 E7 oncoprotein enhance antigen stability and accumulation in tobacco chloroplast. Mol Biotechnol. 2009;43(3):243–249. doi: 10.1007/s12033-009-9195-3. [PubMed] [Cross Ref]
83. Almaraz-Delgado AL, Flores-Uribe J, Pérez-España VH, Salgado-Manjarrez E, Badillo-Corona JA. Production of therapeutic proteins in the chloroplast of Chlamydomonas reinhardtii. AMB Express. 2014;4:57. doi: 10.1186/s13568-014-0057-4. [PMC free article] [PubMed] [Cross Ref]
84. Michoux F, Ahmad N, Hennig A, Nixon PJ, Warzecha H. Production of leafy biomass using temporary immersion bioreactors: an alternative platform to express proteins in transplastomic plants with drastic phenotypes. Planta. 2013;237:903–908. doi: 10.1007/s00425-012-1829-1. [PMC free article] [PubMed] [Cross Ref]
85. Tran M, Van C, Barrera DJ, Pettersson PL, Peinado CD, Bui J, et al. Production of unique immunotoxin cancer therapeutics in algal chloroplasts. Proc Natl Acad Sci USA. 2013;110:E15–E22. doi: 10.1073/pnas.1214638110. [PubMed] [Cross Ref]
86. Wang X, Brandsma M, Tremblay R, Maxwell D, Jevnikar AM, Huner N, et al. A novel expression platform for the production of diabetes-associated auto antigen human glutamic acid decarboxylase (hGAD65) BMC Biotechnol. 2008;8:87. doi: 10.1186/1472-6750-8-87. [PMC free article] [PubMed] [Cross Ref]
87. Yoon S-M, Kim SY, Li KF, Yoon BH, Choe S, Kuo MM-C. Transgenic microalgae expressing Escherichia coli AppA phytase as feed additive to reduce phytate excretion in the manure of young broiler chicks. Appl Microbiol Biotechnol. 2011;91:553–563. doi: 10.1007/s00253-011-3279-2. [PubMed] [Cross Ref]
88. Gregory JA, Topol AB, Doerner DZ, Mayfield S. Alga-produced cholera toxin-Pfs25 fusion proteins as oral vaccines. Appl Environ Microbiol. 2013;79:3917–3925. doi: 10.1128/AEM.00714-13. [PMC free article] [PubMed] [Cross Ref]
89. Manuell AL, Beligni MV, Elder JH, Siefker DT, Tran M, Weber A, et al. Robust expression of a bioactive mammalian protein in Chlamydomonas chloroplast. Plant Biotechnol J. 2007;5:402–412. doi: 10.1111/j.1467-7652.2007.00249.x. [PubMed] [Cross Ref]
90. Tran M, Henry RE, Siefker D, Van C, Newkirk G, Kim J, et al. Production of anti-cancer immunotoxins in algae: ribosome inactivating proteins as fusion partners. Biotechnol Bioeng. 2013;110:2826–2835. doi: 10.1002/bit.24966. [PubMed] [Cross Ref]
91. Surzycki R, Greenham K, Kitayama K, Dibal F, Wagner R, Rochaix J-D, et al. Factors effecting expression of vaccines in microalgae. Biologicals. 2009;37:133–138. doi: 10.1016/j.biologicals.2009.02.005. [PubMed] [Cross Ref]
92. Kupper H, Kepper F, Spiller M. Environmental relevance of heavy metal substituted chlorophylls using the example of water plants. J Exp Bot. 1996;47:259–266. doi: 10.1093/jxb/47.2.259. [Cross Ref]
93. Smits E, Pilon M. Phytoremediation of metals using transgenic plants. Crit Rev Plant Sci. 2002;21:439–456. doi: 10.1080/0735-260291044313. [Cross Ref]
94. Clemens S, Palmgren MG, Kranmer U. A long way ahead: understanding and engineering plant metal accumulation. Trends Plant Sci. 2002;7:309–314. doi: 10.1016/S1360-1385(02)02295-1. [PubMed] [Cross Ref]
95. Hussein H, Ruis ON, Terry N, Daniell H. Phytoremediation of mercury and organomercurials in chloroplast transgenic plants: enhance root uptake, translocation to shoots and volatilization. Environ Sci Technol. 2007;41:8439–8446. doi: 10.1021/es070908q. [PMC free article] [PubMed] [Cross Ref]
96. Occhialini A, Lin MT, Andralojc PJ, Hanson MR, Parry MAJ. Transgenic tobacco plants with improved cyanobacterial Rubisco expression but no extra assembly factors grow at near wild-type rates if provided with elevated CO2. Plant J. 2016;85:148–160. doi: 10.1111/tpj.13098. [PMC free article] [PubMed] [Cross Ref]
97. Bohmert-Tatarev K, McAvoy S, Daughtry S, Peoples OP, Snell KD. High levels of bioplastic are produced in fertile transplastomic tobacco plants engineered with a synthetic operon for the production of polyhydroxybutyrate. Plant Physiol. 2011;155:1690–1708. doi: 10.1104/pp.110.169581. [PubMed] [Cross Ref]
98. Beilen JB, Poirier Y. Production of renewable polymers from crop plants. Plant J. 2008;54:684–701. doi: 10.1111/j.1365-313X.2008.03431.x. [PubMed] [Cross Ref]
99. Snell KD, Peoples OP PHA bioplastic: a value-added coproduct for biomass biorefineries. Biofuel Bioprod Bior. 2009;3:456–467. doi: 10.1002/bbb.161. [Cross Ref]
100. Leelavathi S, Gupta N, Maiti S, Ghosh A, Reddy VS. Overproduction of an alkali- and thermo-stable xylanase in tobacco chloroplasts and efficient recovery of the enzyme. Mol Breed. 2003;11:59–67. doi: 10.1023/A:1022168321380. [Cross Ref]
101. Guda C, Lee SB, Daniell H. Stable expression of a biodegradable protein-based polymer in tobacco chloroplasts. Plant Cell Rep. 2000;19:257–262. doi: 10.1007/s002990050008. [Cross Ref]
102. Castiglia D, Sannino L, Marcolongo L, Ionata E, Tamburino R, Stradis A, et al. High-level expression of thermostable cellulolytic enzymes in tobacco transplastomic plants and their use in hydrolysis of an industrially pretreated Arundo donax L. biomass. Biotechnol Biofuels. 2016;9:154–170. doi: 10.1186/s13068-016-0569-z. [PMC free article] [PubMed] [Cross Ref]
103. Madanala R, Gupta V, Pandey AK, Srivastava S, Pandey V, Singh PK, et al. Tobacco chloroplasts as bioreactors for the production of recombinant superoxide dismutase in plants, an industrially useful enzyme. Plant Mol Biol Rep. 2015;33:1107–1115. doi: 10.1007/s11105-014-0805-2. [Cross Ref]
104. Petersen K, Bock R. High-level expression of a suite of thermostable cell wall-degrading enzymes from the chloroplast genome. Plant Mol Biol. 2011;76:311–321. doi: 10.1007/s11103-011-9742-8. [PubMed] [Cross Ref]
105. Espinoza-Sánchez EA, Álvarez-Hernández MH, Torres-Castillo JA, Rascón-Cruz Q, Gutiérrez-Díez A, Zavala-García F, et al. Stable expression and characterization of a fungal pectinase and bacterial peroxidase genes in tobacco chloroplast. Electron J Biotechnol. 2016;18:161–168. doi: 10.1016/j.ejbt.2015.03.002. [Cross Ref]
106. Verma D, Moghimi B, LoDuca PA, Singh HD, Hoffman BE, Herzog RW, et al. Oral delivery of bioencapsulated coagulation factor IX prevents inhibitor formation and fatal anaphylaxis in hemophilia B mice. Proc Natl Acad Sci USA. 2010;107:7101–7106. doi: 10.1073/pnas.0912181107. [PubMed] [Cross Ref]
107. Gray BN, Yang H, Ahner BA, Hanson MR. An efficient downstream box fusion allows high-level accumulation of active bacterial beta-glucosidase in tobacco chloroplasts. Plant Mol Biol. 2011;76:345–355. doi: 10.1007/s11103-011-9743-7. [PubMed] [Cross Ref]
108. Kim JY, Kanagaraj A, Verma D, Lange T, Daniell H. Production of hyperthermostable GH10 xylanase Xyl10B from Thermotoga maritima in transplastomic plants enables complete hydrolysis of methylglucuronoxylan to fermentable sugars for biofuel production. Plant Mol Biol. 2011;76:357–369. doi: 10.1007/s11103-010-9712-6. [PubMed] [Cross Ref]
109. Xue XY, Mao Y-B, Tao X-Y, Huang Y-P, Chen X-Y. New approaches to agricultural insect pest control based on RNA interference. Adv Insect Physiol. 2012;42:73–117. doi: 10.1016/B978-0-12-387680-5.00003-3. [Cross Ref]
110. Nakahira Y, Ishikawa K, Tanaka K, Tozawa Y, Shiina T. Overproduction of hyperthermostable beta-1,4-endoglucanase from the archaeon Pyrococcus horikoshii by tobacco chloroplast engineering. Biosci Biotechnol Biochem. 2013;77:2140–2143. doi: 10.1271/bbb.130413. [PubMed] [Cross Ref]
111. Pantaleoni L, Longoni P, Ferroni L, Baldisserotto C, Leelavathi S, Reddy VS, Pancaldi S, et al. Chloroplast molecular farming: efficient production of a thermostable xylanase by Nicotiana tabacum plants and long-term conservation of the recombinant enzyme. Protoplasma. 2014;251:639–648. doi: 10.1007/s00709-013-0564-1. [PubMed] [Cross Ref]
112. Yu LX, Gray BN, Rutzke CJ, Walker LP, Wilson DB, Hanson MR. Expression of thermostable microbial cellulases in the chloroplasts of nicotine-free tobacco. J Biotechnol. 2007;131:362–369. doi: 10.1016/j.jbiotec.2007.07.942. [PubMed] [Cross Ref]
113. Ahmad N, Michoux F, Lössl AG, Nixon PJ. Challenges and perspectives in commercializing plastid transformation technology. J Exp Bot. 2016;67(21):5945–5960. doi: 10.1093/jxb/erw360. [PubMed] [Cross Ref]
114. Ahmadabadi M, Ruf S, Bock R. A leaf-based regeneration and transformation system for maize (Zea mays L.) Transgenic Res. 2007;16:437–448. doi: 10.1007/s11248-006-9046-y. [PubMed] [Cross Ref]
115. Ahmad N, Michoux F, Nixon PJ. Investigating the production of foreign membrane proteins in tobacco chloroplasts: expression of an algal plastid terminal oxidase. PLoS ONE. 2012;7:417–422. [PMC free article] [PubMed]
116. Kahlau S, Bock R. Plastid transcriptomics and translatomics of tomato fruit development and chloroplast-to-chromoplast differentiation: chromoplast gene expression largely serves the production of a single protein. Plant Cell. 2008;20:856–874. doi: 10.1105/tpc.107.055202. [PubMed] [Cross Ref]
117. Valkov T, Scotti N, Kahlau S, MacLean D, Grillo S, Gray JC, et al. Genome-wide analysis of plastid gene expression in potato leaf chloroplasts and tuber amyloplasts: transcriptional and posttranscriptional control. Plant Physiol. 2009;150:2030–2044. doi: 10.1104/pp.109.140483. [PubMed] [Cross Ref]
118. Zhang J, Ruf S, Hasse C, Childs L, Scharff LB, Bock R. Identification of cis-elements conferring high levels of gene expression in non-green plastids. Plant J. 2012;72:115–128. doi: 10.1111/j.1365-313X.2012.05065.x. [PubMed] [Cross Ref]
119. Iamtham S, Day A. Removal of antibiotic resistance genes from transgenic tobacco plastids. Nat Biotechnol. 2000;18:1172–1176. doi: 10.1038/81161. [PubMed] [Cross Ref]
120. Zhou F, Badillo-Corona JA, Karcher D, Gonzalez-Rabade N, Piepenburg K, Borchers AMI, et al. High-level expression of human immunodeficiency virus antigens from the tobacco and tomato plastid genomes. Plant Biotechnol J. 2008;6:897–913. doi: 10.1111/j.1467-7652.2008.00356.x. [PubMed] [Cross Ref]
121. Apel W, Schulze WX, Bock R. Identification of protein stability determinants in chloroplasts. Plant J. 2010;63:636–650. doi: 10.1111/j.1365-313X.2010.04268.x. [PMC free article] [PubMed] [Cross Ref]
122. Sheppard AE, Madesis P, Lloyd AH, Day A, Ayliffe MA, Timmis JN. Introducing an RNA editing requirement into a plastidlocalised transgene reduces but does not eliminate functional gene transfer to the nucleus. Plant Mol Biol. 2011;76:299–309. doi: 10.1007/s11103-011-9764-2. [PubMed] [Cross Ref]

Articles from Plant Methods are provided here courtesy of BioMed Central