Role of SAGs and development of disease resistant transgenics in rice

Plant senescence is a highly complex but ordered process which affects plant development from seed germination to maturity. It involves expression of large number of senescence associated genes (SAGs) which play an important and physiological role in the source to sink relationship in the plant system. So, it is very important to find out these genes and study their effects and develop strategies to improve different crops. This book contains the work carried out on isolation and cloning of homologs of Arabidopsis SAG12 (AtSAG12) gene which codes for papain-like cysteine protease involved in senescence. tBLASTN search tool was used and OsSAG12-1 and OsSAG12-2 homologues were found closest to AtSAG12 with 64% and 65% similarity. RNAi lines were generated through Agrobacterium mediated transformation and characterized further by Southern Blot, RT-PCR, GUS assay. In addition, transgenic rice was developed with AtNPR1 over expression construct which shows high level of resistance against pathogens without any growth penalty. Thus, these findings will be helpful to generate disease resistant plants and delay senescence to prolong their life.