WRR4C gene positively regulates the disease resistance of Arabidopsis to Oidium heveae and Erysiphe polygoni
Oidium heveae is an incompatible pathogen of Arabidopsis Col-0,and triggers disease resistance in Arabidopsis in an EDS1(ENHANCED DISEASE SUSCEPTIBILITY 1)and PAD4(PHYTOALEXIN DEFI-CIENT 4)dependent manner,suggesting that TIR-NB-LRR(TOLL INTERLEUKIN 1 RECEPTOR,NUCLEO-TIDE-BINDING,LEUCINE-RICH REPEAT)genes may involve in the disease resistance against O.heveae.In this study,the differentially expressed TIR-NB-LRR genes targeting O.heveae were screened,and the expres-sion of WRR4C(WHITE RUST RESISTANCE 4C)gene was found to up-regulated induced by O.heveae.Through inoculation assay,O.heveae was observed to develop dense hyphal network and a few conidia in two wrr4c single mutants,and triggered significantly decreased defense responses including cell death,callose depo-sition and PRI(Pathogenesis Related 1)gene expression,indicating that WRR4C positively regulated the disease resistance of Arabidopsis against the powdery mildew of Hevea brasiliensis.However,WRR4C gene did not par-ticipate in the cell pre-penetration resistance to O.heveae,and the expression of WRR4C reached to the highest level at 48 hours post inoculation,suggesting that WRR4C genes was mainly involved in the cell post-penetration resistance of Arabidopsis to O.heveae.In addition,we found WRR4C also positively regulated the disease resistance against Erysiphe polygoni in Arabidopsis.