Glycerol-Induced Powdery Mildew Resistance in Wheat by Regulating Plant Fatty Acid Metabolism, Plant Hormones Cross-Talk, and Pathogenesis-Related Genes

Abstract

Our previous study indicated that glycerol application induced resistance to powdery mildew (Bgt) in wheat by regulating two important signal molecules, glycerol-3-phosphate (G3P) and oleic acid (OA18:1). Transcriptome analysis of wheat leaves treated by glycerol and inoculated with Bgt was performed to identify the activated immune response pathways. We identified a set of differentially expressed transcripts (e.g., TaGLI1, TaACT1, and TaSSI2) involved in glycerol and fatty acid metabolism that were upregulated in response to Bgt infection and might contribute to G3P and OA18:1 accumulation. Gene Ontology (GO) enrichment analysis revealed GO terms induced by glycerol, such as response to jasmonic acid (JA), defense response to bacterium, lipid oxidation, and growth. In addition, glycerol application induced genes (e.g., LOX, AOS, and OPRs) involved in the metabolism pathway of linolenic and alpha-linolenic acid, which are precursor molecules of JA biosynthesis. Glycerol induced JA and salicylic acid (SA) levels, while glycerol reduced the auxin (IAA) level in wheat. Glycerol treatment also induced pathogenesis related (PR) genes, including PR-1, PR-3, PR-10, callose synthase, PRMS, RPM1, peroxidase, HSP70, HSP90, etc. These results indicate that glycerol treatment regulates fatty acid metabolism and hormones cross-talk and induces the expression of PR genes that together contribute to Bgt resistance in wheat.

Comparative transcriptome analysis of two contrasting resistant and susceptible Aegilops tauschii accessions to wheat leaf rust (Puccinia triticina) using RNA-sequencing

“…Also, Tang et al 59 stated calcium influx activates MAPK cascades which in turn promote stomatal closure to limit the pathogen’s entry into leaves. Furthermore, the ‘ AET1Gv20702500 ’ gene encoding UTP-glucose-1-phosphate uridylyltransferase (UDPGP), was up-regulated in the ‘glycerolipid metabolism’ pathway, which is expected to mediate disease resistance responses 60 . Therefore, these genes may be implicated in resistance, supporting their role in Ae.…”

Comparative analysis of powdery mildew resistant and susceptible cultivated cucumber (Cucumis sativus L.) varieties to reveal the metabolic responses to Sphaerotheca fuliginea infection

“…Previous studies showed that fatty acid metabolism as well as lipid signaling have a close relevance to PM resistance [ 50 ]. For example, several wheat fatty acids, such as C12:0, C18:1, C18:2 and C20:2, were significantly changed by PM infection [ 51 ].…”

“…For example, several wheat fatty acids, such as C12:0, C18:1, C18:2 and C20:2, were significantly changed by PM infection [ 51 ]. Further study showed that the regulation of fatty acid metabolism was requried for glycerol-induced PM resistance in wheat [ 50 ]. In our study, the number of fatty acid metabolism-related DAMs in H136 (290 metablites) was larger than that in BK2 (132 metablites), indicating an active fatty acid metabolism in the PM-susceptible variety.…”

Resistance inducers and their role in reinforcing wheat defense system against fungal pathogens

“…and HSP90) which together can strengthen wheat resistance potentialities against B. graminis f. sp. tritici (Li et al, 2020). Further, it has been noticed that glycerol induced JA and SA levels, while reduced the auxin (IAA) levels in wheat in response to fungal infection lead to the accumulation of glycerol-3-phosphate (G3P) and oleic acid (OA18:1) metabolites at the zone of infection.…”