Title : Transcriptional regulation of defense responsive genes during wheat-stripe rust interactions
Abstract:
Stripe or yellow rust disease of wheat is caused by Puccinia striiformis Westend. f.sp. tritici (Pst) is a global threat to wheat production. Populations of Pst pathotypes evolves rapidly, limits the efficiency of plant genetic resistance and constrict the strategies of disease management. Molecular mechanisms that lead the infection and spread of disease could convey the novel strategies for deployment of rust resistance in wheat. Genetic modifications of defense responsive factors under compatible interactions could be one of the way to produce resistance towards emerging virulent pathotypes. The present study is planned to understand the interaction between Pst pathotype 78S84 in PBW 343 and FLW-3. A quantitative temporal transcription profile of selected defense related genes (caffeic acid O-methyltransferase (COMT1), class III peroxidase (PRA2), Type 1 non-specific lipid transfer protein precursor (LTP1), chlorophyll a/b-binding protein WCAB precursor (WCAB), aquaporin (AQP1), β-1,3-glucanase (PR1 and PR2), endochitinase (PR4), peroxidase (PR9) and phenylalanine ammonia-lyase (PR10)) was analyzed at different time course of infection. Under compatible and incompatible interactions, at different time course after inoculation differential expression pattern of genes was observed which indicated the different transcription levels of defense related genes in response to pathogen attack. Under compatible interactions, most of the genes were upregulated at initial time points and then transcription levels of the genes were declined. Nevertheless, under incompatible interactions transcription level was higher from 3 to 24hpi, which is considered as the favorable time for appressorial hyphae, haustorial mother cell development and formation of feeding structure. Genes LTP, AQP1, PR1, PR2, PR4 and PR10 confer pre-haustorial resistance under incompatible interactions. On other hand, COMT1, PRA2, WCAB and PR9 genes showed higher transcription level at later stages and governs post-haustorial resistance. Under compatible interactions LTP, AQP1, PR1, PR2, PR4 and PR10 genes performed well and showed higher transcription efficiency while under incompatible interactions transcript levels of COMT1, PRA2, WCAB and PR9 genes were found significantly high. Results of this study clearly depicted the role of defense responsive genes with progression of disease under compatible and incompatible interactions.
