Cuticular wax modification by Epichloë endophyte in Achnatherum inebrians under Blumeria graminis infection

Achnatherum inebrians is a perennial plant belonging to the Poaceae, subfamily Pooideae, which often forms a symbiosis with fungal endophytes of the genus Epichloë . In this study, E . gansuensis -infected (E+) and E . gansuensis -free (E−) A . inebrians were inoculated with Blumeria graminis (pathogen-inoculated, P+; non-inoculated, P−) under greenhouse conditions. Gas chromatography-mass spectrometry (GC-MS) and transcriptome sequencing were combined to characterize the response of the leaf cuticular wax of A . inebrians plants with and without the Epichloë endophyte to B . graminis stress. The present results revealed that the predominant components of the cuticular wax of A . inebrians leaves under the Epichloë endophyte and B . graminis treatments were hydrocarbons, esters, and fatty acids. The total cuticular wax and ester contents of the E+ and E− A . inebrians leaves significantly ( p < 0.05) increased under the B . graminis treatment, but the total cuticular wax and ester contents of the E+ leaves were greater than those of the E− plants. Through transcriptome analysis, 15 genes that were differentially expressed and related to cuticular wax biosynthesis were identified, including fadD , fadF , TER , SSI2 , BiP , CER1 , FAR , and KCS .