Sarmah, Bidyut KumarGupta, Rubi2020-05-292020-05-292019-10http://krishikosh.egranth.ac.in/handle/1/5810146700iosafety assessment of transgenic chickpeas having B.thuringiensis genes for resistance to pod borers is a regulatory requirement and mandatory to document before releasing in the field. Therefore, Bt chickpea lines harbouring either a cry1Ac or cry2Aa gene were characterized for the presence and expression of the transgene in their advanced generations, biosafety assessments and transcript profile were studied. The homozygous lines were selected for comparative nutritional equivalence assay. Biochemical estimations of major nutritional components such as proximates, vitamins, minerals, fatty acids and anti nutrients confirmed that the Bt chickpeas lines are nutritionally equivalent to their non-transgenic counterparts and the seed composition is similar or within the range reported, previously. Seed protein quality was investigated by separating the proteins in PAGE and eluted proteins after mass spectrometry (MS) showed expected fractions of 11S legumin, 7S vicilin, and 2S albumin of chickpea storage proteins in the transgenic lines. The protein digestibility was assayed using the multi-enzyme system and transient pepsin hydrolysis to mimic simulated gastric fluid followed by trypsin hydrolysis to mimic simulated intestinal fluid. Total seed proteins of both the transgenic and nontransgenic lines were digested at a similar rate and enzyme-resistant peptides were not observed in transgenic Bt chickpea lines. The unintended changes in the whole transcriptome profile of Bt chickpeas were surveyed using a homozygous transgenic line expressing a cry1Ac gene. The differentially expressed genes (DEGs) profiling confirmed a low (0.69%, log2fold changeā„2) frequency of differentially expressed in the transgenic chickpea line. Only a small (34 upregulated) proportion of genes showed > 2 fold (P-value of 0.05, FDR of 0.05) change in their expression, while only 23 genes down-regulated by >2 fold. Furthermore, no transcripts for potential allergenic proteins were represented in the DEGs. Most of these genes appeared to be developmentally regulated or stress-related which was expected because absolute synchronous growth and development even under a controlled environment are challenging. A few upregulated (AT-hook motif nuclear-localized protein 17-like, probable inactive 2-oxoglutaratedependent dioxygenase AOP2, protein EXORDIUM-like) and down-regulated (histone H2B, gonadal, embryonic abundant protein VF30.1-like, fasciclin-like arabinogalactan protein 12) genes were subjected to qPCR. The qPCR data validated the fold change of the up-regulated (>2) and down-regulated (>-2) genes. Thus, the above data revealed no potential alterations in the nutritional equivalence or transcript profile of transgenic Bt chickpeas.enMolecular characterization and nutritional equivalence evaluation of transgenic chickpea expressing either a cry1Ac or cry2Aa genThesis