Cuticular Wax Modification by Epichloë Endophyte in Achnatherum inebrians under Different Soil Moisture Availability

The cuticular wax serves as the outermost hydrophobic barrier of plants against nonstomatal water loss and various environmental stresses. An objective of this study was to investigate the contribution of the mutualistic fungal endophyteEpichloë gansuensisto leaf cuticular wax ofAchnatherum inebriansunder different soil moisture availability. Through a pot experiment and gas chromatography−mass spectrometry (GC−MS) analysis, our results indicated that the hydrocarbons were the dominant components of leaf cuticular wax, and the proportion of alcohols, aldehydes, amines, and ethers varied with the presence or absence ofE. gansuensisand different soil moisture availability. Amines and ethers are unique in endophyte-free (EF)A. inebriansplants and endophyte-infected (EI)A. inebriansplants, respectively. By transcriptome analysis, we found a total of 13 differentially expressed genes (DEGs) related to cuticular biosynthesis, includingFabG,desB,SSI2,fadD,BiP,KCS,KAR,FAR, andABCB1. A model is proposed which provides insights for understanding cuticular wax biosynthesis in the association ofA. inebriansplants withE. gansuensis.These results may help guide the functional analyses of candidate genes important for improving the protective layer of cuticular wax of endophyte-symbiotic plants.Keywords:Epichloë gansuensis;Achnatherum inebrians;soil moisture availability;cuticular wax;gas chromatography−mass spectrometry;transcriptome analysis