GSE161152
A MKP-MAPK protein phosphorylation cascade controls vascular disease resistance in plants
Vascular plant diseases, such as rice bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo) and crucifer black rot caused by Xanthomonas campestris pv. campestris (Xcc), cause huge yield loss of crops worldwide. However, how plants operate vascular defense against these obligate pathogens remains elusive. In this study, we used both Arabidopsis and rice pathosystems to address the long-standing question.  We found that the loss of function mutation of Arabidopsis mitogen-activated protein kinase (MAPK) phosphatase 1 (MKP1) lost the non-host resistance to Xoo and supported Xoo to grow in the leaf veins, which also enhanced susceptibility to Xcc. MKP1 regulates the MPK3-mediated phosphorylation of the transcription factor MYB4 that functions in vascular lignification. Importantly, the MKP-MAPK cascade-mediated lignin biosynthesis is also conserved in rice through regulating OsMYB102 and OsMYB108, which control rice vascular resistance to adapted Xoo. Interestingly, the Arabidopsis and rice mutants enhanced resistance to the mesophyll cell pathogens most likely through upregulating salicylic acid biosynthesis, Pseudomonas syringae (P. syringae) and Xanthomonas oryzae pv. oryzicole (Xoc), respectively; strongly suggesting that this immune mechanism is likely specific to the obligate vascular pathogens. Therefore, our study uncovers a previously unrecognized vascular-specific and lignin-based immune mechanism, shedingshedding new sight on tissue-specific immunity in plants, as well as providing a practical approach for improvement of disease resistance against vascular pathogens in crops Overall design: arabidopsis mRNA profiles of 4-week old wild type and mutant