Arabidopsis phospholipase D?1 and D? oppositely modulate EDS1- and SA-independent basal resistance against adapted powdery mildew.

ABSTRACT: Plants use a tightly regulated immune system to fight off various pathogens. Phospholipase D (PLD) and its product, phosphatidic acid, have been shown to influence plant immunity; however, the underlying mechanisms remain unclear. Here, we show that the Arabidopsis mutants pld?1 and pld?, respectively, exhibited enhanced resistance and enhanced susceptibility to both well-adapted and poorly adapted powdery mildew pathogens, and a virulent oomycete pathogen, indicating that PLD?1 negatively while PLD? positively modulates post-penetration resistance. The pld?1? double mutant showed a similar infection phenotype to pld?1, genetically placing PLD?1 downstream of PLD?. Detailed genetic analyses of pld? with mutations in genes for salicylic acid (SA) synthesis (SID2) and/or signaling (EDS1 and PAD4), measurement of SA and jasmonic acid (JA) levels, and expression of their respective reporter genes indicate that PLD? contributes to basal resistance independent of EDS1/PAD4, SA, and JAsignaling. Interestingly, while PLD?1-enhanced green fluorescent protein (eGFP) was mainly found in the tonoplast before and after haustorium invasion, PLD?-eGFP's focal accumulation to the plasma membrane around the fungal penetration site appeared to be suppressed by adapted powdery mildew. Together, our results demonstrate that PLD?1 and PLD? oppositely modulate basal, post-penetration resistance against powdery mildew through a non-canonical mechanism that is independent of EDS1/PAD4, SA, and JA.

SUBMITTER: Zhang Q 

PROVIDER: S-EPMC6022666 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature