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author:("Cao, qinghai")
1.  Do transgenesis and marker-assisted backcross breeding produce substantially equivalent plants? - A comparative study of transgenic and backcross rice carrying bacterial blight resistant gene Xa21 
BMC Genomics  2013;14:738.
The potential impact of genetically modified (GM) plants on human health has attracted much attention worldwide, and the issue remains controversial. This is in sharp contrast to the broad acceptance of plants produced by breeding through Marker Assisted Backcrossing (MAB).
Focusing on transcriptome variation and perturbation to signaling pathways, we assessed the molecular and biological aspects of substantial equivalence, a general principle for food safety endorsed by the Food and Agricultural Organization and the World Health Organization, between a transgenic crop and a plant from MAB breeding. We compared a transgenic rice line (DXT) and a MAB rice line (DXB), both of which contain the gene Xa21 providing resistance to bacterial leaf blight. By using Next-Generation sequencing data of DXT, DXB and their parental line (D62B), we compared the transcriptome variation of DXT and DXB. Remarkably, DXT had 43% fewer differentially expressed genes (DEGs) than DXB. The genes exclusively expressed in DXT and in DXB have pathogen and stress defense functions. Functional categories of DEGs in DXT were comparable to that in DXB, and seven of the eleven pathways significantly affected by transgenesis were also perturbed by MAB breeding.
These results indicated that the transgenic rice and rice from MAB breeding are substantial equivalent at the transcriptome level, and paved a way for further study of transgenic rice, e.g., understanding the chemical and nutritional properties of the DEGs identified in the current study.
PMCID: PMC4007521  PMID: 24165682
Transgenesis; Marker-assisted backcrossing; Substantial equivalence; Transcriptome profile; Xa21
2.  Identifying the Genome-Wide Sequence Variations and Developing New Molecular Markers for Genetics Research by Re-Sequencing a Landrace Cultivar of Foxtail Millet 
PLoS ONE  2013;8(9):e73514.
Foxtail millet (Setariaitalica) is a drought-resistant, barren-tolerant grain crop and forage. Currently, it has become a new model plant for cereal crops and biofuel grasses. Although two reference genome sequences were released recently, comparative genomics research on foxtail millet is still in its infancy. Using the Solexa sequencing technology, we performed genome re-sequencing on one important foxtail millet Landrace, Shi-Li-Xiang (SLX). Compared with the two reference genome sequences, the following genetic variation patterns were identified: 762,082 SNPs, 26,802 insertion/deletion polymorphisms of 1 to 5 bp in length (indels), and 10,109 structural variations (SVs) between SLX and Yugu1 genomes; 915,434 SNPs, 28,546 indels and 12,968 SVs between SLX and Zhang gu genomes. Furthermore, based on the Yugu1 genome annotation, we found out that ~ 40% SNPs resided in genes containing NB-ARC domain, protein kinase or leucine-rich repeats, which had higher non-synonymous to synonymous SNPs ratios than average, suggesting that the diversification of plant disease resistance proteins might be caused by pathogen pressure. In addition, out of the polymorphisms identified between SLX and Yugu1, 465 SNPs and 146 SVs were validated with more than 90% accuracy, which could be used as DNA markers for whole-genome genotyping and marker-assisted breeding. Here, we also represented an example of fine mapping and identifying a waxy locus in SLX using these newly developed DNA markers. This work provided important information that will allow a deeper understanding of the foxtail millet genome and will be helpful for dissecting the genetic basis of important traits in foxtail millet.
PMCID: PMC3769310  PMID: 24039970
3.  Identification and validation of rice reference proteins for western blotting 
Journal of Experimental Botany  2011;62(14):4763-4772.
Studies of rice protein expression have increased considerably with the development of rice functional genomics. In order to obtain reliable expression results in western blotting, information on appropriate reference proteins is necessary for data normalization. To date, no published study has identified and systematically validated reference proteins suitable for the investigation of rice protein expression. In this study, nine candidate proteins were selected and their specific antibodies were obtained through immunization of rabbits with either recombinant proteins expressed in Escherichia coli or synthesized peptides. Western blotting was carried out to detect the expression of target proteins in a set of 10 rice samples representing different rice tissues/organs at different developmental stages. The expression stability of the proteins was analysed using geNorm and Microcal Origin 6.0 software. The results indicated that heat shock protein (HSP) and elongation factor 1-α (eEF-1α) were the most constantly expressed among all rice proteins tested throughout all developmental stages, while the proteins encoded by conventional internal reference genes fluctuated in amount. Comparison among the profiling of translation and transcription [expressed sequence tags (EST) and massively parallel signature sequencing (MPSS)] revealed that a correlation existed. Based on the standard curves derived from the antigen–antibody reaction, the concentrations of HSP and eEF-1α proteins in rice leaves were ∼0.12%. Under the present experimental conditions, the lower limits of detection for HSP and eEF-1α proteins in rice were 0.24 ng and 0.06 ng, respectively. In conclusion, the reference proteins selected in this study, and the corresponding antibodies, can be used in qualitative and quantitative analysis of rice proteins.
PMCID: PMC3192993  PMID: 21705388
Antibody-based proteomics; rice (Oryza sativa L.); reference gene; reference protein; western blotting

Results 1-3 (3)