Isoflavonoid‐specific prenyltransferase gene family in soybean: GmPT01, a pterocarpan 2‐dimethylallyltransferase involved in glyceollin biosynthesis

Abstract

Phytoalexin glyceollins are soybean-specific antimicrobial compounds that are derived from the isoflavonoid pathway. They are synthesized by soybean in response to extrinsic stress such as pathogen attack or injury, thereby conferring partial resistance if synthesized rapidly at the site of infection and at the required concentration. Soybean produces multiple forms of glyceollins that result from the differential prenylation reaction catalyzed by prenyltransferases (PTs) on either the C-2 or C-4 carbon of a pterocarpan glycinol. The soybean genome contains 77 PT-encoding genes (GmPTs) where at least 11 are (iso)flavonoid-specific. Transcript accumulation of five candidates GmPTs was increased in response to Phytophthora sojae infection, suggesting their role in phytoalexin synthesis. The induced GmPTs localize to plastids and display tissue-specific expression. We have in this study identified two additional GmPTs: an isoflavone dimethylallyltransferase 3 (IDT3); and a glycinol 2-dimethylallyl transferase GmPT01. GmPT01 prenylates (-)-glycinol at the C-2 position, localizes in the plastid, and exhibits root-specific gene expression. Furthermore, its expression is induced rapidly in response to stress, and is associated with a quantitative trait loci linked with resistance to P. sojae. Based on these results, we conclude that GmPT01 are possibly one of the loci involved in conferring partial resistance against stem and root rot disease in soybean.

Pseudomonas fluorescens MZ05 Enhances Resistance against Setosphaeria turcica by Mediating Benzoxazinoid Metabolism in the Maize Inbred Line Anke35

“…Plants can defend against multiple biotic factors by the constitutive and inducible defense mechanisms [1][2][3]. The inducible defenses encompass various strategies, such as the promoted biosynthesis of phytoalexins [28][29][30][31], the enhanced activities of enzymes involved in the biosynthesis of antimicrobial compounds [32][33][34], and the increased expression of pathogenesis-related (PR) proteins [35][36][37][38]. Phytoalexins have been identified as important antimicrobial metabolites for plant defense against pathogens and pests [28][29][30][31].…”

Isoflavones

“…Often, more than one type can be found in a single plant species and the same isoflavonoids may be produced by different plant species. In soybean, daidzein is metabolized to produce glyceollins, which serve as defense mechanisms against several, primarily fungal, pathogens [30]. In the model legume Medicago truncatula , formononetin is metabolized into medicarpin, a phytoalexin that is conncected with pathogen resistance [31].…”

The Effects of Domestication on Secondary Metabolite Composition in Legumes

“…Molecular characterization of PT genes revealed that G4DT and G2DT are paralogs resulting from a whole-genome duplication (Yoneyama et al, 2016). A genome-wide analysis of PT genes in G. max Wm82 identified 77 PT-encoding genes with 11 putative isoflavonoid-specific PTs (Sukumaran et al, 2018). One of the candidate genes, GmPT01 (G2DT-2) was induced by P. sojae infection and AgNO 3, which mimics pathogen attack and lies in the QTL linked to P. sojae resistance.…”