SAG101 And ROH1 Contribute To The Oidium Heveae-triggered Disease Resistance In Arabidopsis

The powdery mildew disease of rubber trees is caused by Oidium heveae,an obligate biotrophic pathogen on Heveae brasiliensis.It has been reported that O.heveae HN1106 triggers the hypersensitive response in a manner that depends on the EDS1 and PAD4 in the model plant Arabidopsis thaliana.Previous study has shown that EDS1,PAD4 and SAG101 can form a single complex to mediate disease resistance,however,it is unknown whether SAG101 is required for O.heveae triggered disease resistance in Arabidopsis.In this study,WT Col-0,sag101,edsl and pad4 mutants were inoculated with O.heveae HN1106.The results shown that the early stage,late stage disease resistance and defense responses triggered by O.heveae in sag101,edsl and pad4 mutants were significantly decreased than that in WT Col-0.And the order of the mutants susceptibility to O.heveae is edsl>pad4>sag101.Overall,this study indicates that both EDS1,PAD4 and SAG101 contribute to the disease resistance against O.heveae,and a cooperativity may be existed between PAD4 and SAG101 in the resistance.Recent studies have reported that Oidium heveae-triggered disease resistance in Aranbidopsis is an EDS1 but not NDR1 dependent,suggesting that TIR-NB-LRR genes are involved in the disease resistance to Oidium heveae(ROH).However,it remains unknown which TIR-NB-LRR gene(s)can recognize the Oidium heveae.In this study,we perform the RNA-seq analysis of WT Col-0 infected with Oidium heveae at 0,2,4,8 days post inoculation.The results showed that the expression of 8 TIR-NB-LRR type genes are up-regulated and 3 genes are down-regulate.Furthermore,the homozygous T-DNA insertions lines of the 11 genes were identified and inoculated by Oidium heveae HN1106.The results confirmed that TIR NB LRR type gene AT1G56510(ROH1).contributes to the disease resistance against Oidium heveae.Furthermore,we found ROH1 can locate on the plant membrane to fulfill its function.