WRR4C基因正调控拟南芥对橡胶树白粉菌和豇豆白粉菌的抗病性

WRR4C gene positively regulates the disease resistance of Arabidopsis to Oidium heveae and Erysiphe polygoni

橡胶树白粉菌(Oidium heveae)与拟南芥野生型Col-0是一种非亲和相互作用,激发依赖于EDS1(ENHANCED DISEASE SUSCEPTIBILITY 1)和PAD4(PHYTOALEXIN DEFICIENT 4)的抗病性,推测TIR-NB-LRR(TOLL INTERLEUKIN 1 RECEPTOR NUCLEOTIDE-BINDING LEUCINE-RICH REPEATS)类抗病基因参与对O.heveae的抗病性。本研究通过筛选针对O.heveae的TIR-NB-LRR类差异表达基因,发现WRR4C(white rust resistance 4 C)基因受O.heveae的诱导上调表达。经过表型分析鉴定,O.heveae可以在2个wrr4c单突变体上形成浓密的菌丝网络和少量的分生孢子。同时,O.heveae在wrr4c突变体上激发的细胞死亡、胼胝体沉积和致病相关基因PR1(Pathogenesis related 1)的表达都显著降低,暗示着WRR4C基因正调控拟南芥对橡胶树白粉菌的抗病性。然而,通过白粉菌细胞进入率测定,WRR4C基因并不参与拟南芥对O.heveae的细胞进入抗性。进一步利用荧光定量PCR分析发现,WRR4C基因受O.heveae的诱导,在侵染后的48 h表达量达到最高,推测WRR4C基因主要在白粉菌细胞进入后发挥抗病功能。另外,通过接种豇豆白粉菌,发现WRR4C基因同时正调控拟南芥对豇豆白粉菌的抗病性。

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 DEFICIENT 4)dependent manner,suggesting that TIR-NB-LRR(TOLL INTERLEUKIN 1 RECEPTOR,NUCLEOTIDE-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 expression 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 deposition and PR1(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 participate 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.