Ethylene signaling regulates natural variation in the abundance of antifungal acetylated diferuloylsucroses andFusarium graminearumresistance in maize seedling roots

Abstract

SummaryThe production and regulation of defensive specialized metabolites plays a central role in pathogen resistance in maize (Zea mays) and other plants. Therefore, identification of genes involved in plant specialized metabolism can contribute to improved disease resistance.We used comparative metabolomics to identify previously unknown antifungal metabolites in maize seedling roots, and investigated the genetic and physiological mechanisms underlying their natural variation using quantitative trait locus (QTL) mapping and comparative transcriptomics approaches.Two maize metabolites, smilaside A (3,6-diferuloyl-3′,6′-diacetylsucrose) and smiglaside C (3,6-diferuloyl-2′,3′,6′-triacetylsucrose), that may contribute to maize resistance against Fusarium graminearum and other fungal pathogens were identified. Elevated expression of an ethylene receptor gene, ETHYLENE INSENSITIVE 2 (ZmEIN2), co-segregated with decreased smilaside A/smiglaside C ratio. Pharmacological and genetic manipulation of ethylene availability and sensitivity in vivo indicated that, whereas ethylene was required for the production of both metabolites, the smilaside A/smiglaside C ratio was negatively regulated by ethylene sensitivity. This ratio, rather than the absolute abundance of these two metabolites, was important for maize seedling root defense against F. graminearum.Ethylene signaling regulates the relative abundance of the two F. graminearum-resistance-related metabolites and affects resistance against F. graminearum in maize seedling roots.

Multi-Omics Analysis Reveals a Regulatory Network of ZmCCT During Maize Resistance to Gibberella Stalk Rot at the Early Stage

“…The single transcriptomic analysis provides a landscape of defense response at a given time point (Ye et al, 2013); however, not all transcriptional changes observed are translated into proteins or metabolites. Therefore, combining transcriptomic data with those proteomic and metabolomic approaches can be used to comprehensively reveal the multilevel landscape of plant defense response and better understand the molecular mechanism of GSR resistance (Zhou et al, 2019;Sun et al, 2021). Recently, an integrative analysis combining transcriptomics and metabolomics showed that ZmHIR3 controls cell death at the later stage of GSR, probably through the transcriptional regulation of key genes and functional metabolites (Sun et al, 2021).…”