Global analysis of threonine metabolism genes unravel key players in rice to improve the abiotic stress tolerance.

The diversity in plant metabolites with improved phytonutrients is essential to achieve global food security and sustainable crop yield. Our study using computational metabolomics genome wide association study (cmGWAS) reports on a comprehensive profiling of threonine (Thr) metabolite in rice. Sixteen abiotic stress responsive (AbSR) - Thr metabolite producing genes (ThrMPG), modulate metabolite levels and play a significant role determining both physiological and nutritional importance of rice. These AbSR-ThrMPG were computationally analysed for their protein properties using OryzaCyc through plant metabolic network analyser. A total of 1373 and 1028 SNPs were involved in complex traits and genomic variations. Comparative mapping of AbSR-ThrMPG revealed the chromosomal colinearity with C4 grass species. Further, computational expression pattern of these genes predicted a differential expression profiling in diverse developmental tissues. Protein interaction of protein coding gene sequences revealed that the abiotic stresses (AbS) are multigenic in nature. In silico expression of AbSR-ThrMPG determined the putative involvement in response to individual AbS. This is the first comprehensive genome wide study reporting on AbSR -ThrMPG analysis in rice. The results of this study provide a pivotal resource for further functional investigation of these key genes in the vital areas of manipulating AbS signaling in rice improvement.

Rapid regeneration and ploidy stability of 'cv IR36' indica rice (Oryza Sativa. L) confers efficient protocol for in vitro callus organogenesis and Agrobacterium tumefaciens mediated transformation.

BACKGROUND: Cereal crops are the major targets for transformation mediated crop improvement and IR36 is an early maturing, high yielding, insect and disease resistant rice variety however, it is abiotic stress sensitive. Hence, development of an efficient and reproducible micropropagation system via somatic embryogenesis and Agrobacterium tumefaciens mediated transformation is prerequisite to develop abiotic stress tolerant IR36. Further, Genetic stability of analysis of plantlets through RAPD and ISSR and Ploidy level through Flow cytometry (FCM) measurement of 2C DNA content is necessary for future application of transformed IR36. RESULTS: In this study, Mature seeds inoculated on (Murashige and Skoog) MS medium with 11.31 µM 2, 4-dichlorophenoxyacetic acid (2, 4-D) and 0.3 µM Kinetin (Kn) had highest callus induction frequency (98%). The highest regeneration frequency (80%) was observed in MS + 13.28 µM Benzyladenine (BA) with 8.06 µM α-naphthalene acetic acid (NAA). Randomly Amplified Polymorphic DNA (RAPD), Inter Simple Sequence Repeat (ISSR) and Flow Cytometry (FCM) analysis showed no significant variation in the 2C DNA (0.81 pg/2C) content and Ploidy level between wild type IR36 and in vitro maintained rice lines. Of the various OD bacterial culture, an optimum OD of 0.4 and inoculation duration of 10 min resulted in efficient Agrobacterium-mediated transformation. ß-glucuronidase activity was maximum in callus (99.05%). CONCLUSIONS: These results described here confirm the reliability of this protocol for micropropagation and delivery of desirable gene using A. tumefaciens into indica rice.