Constitutive overexpression of GsIMaT2 gene from wild soybean enhances rhizobia interaction and increase nodulation in soybean (Glycine max)

Abstract

Background Since the root nodules formation is regulated by specific and complex interactions of legume and rhizobial genes, there are still too many questions to be answered about the role of the genes involved in the regulation of the nodulation signaling pathway. Results The genetic and biological roles of the isoflavone-7-O-beta-glucoside 6″-O-malonyltransferase gene GsIMaT2 from wild soybean (Glycine soja) in the regulation of nodule and root growth in soybean (Glycine max) were examined in this work. The effect of overexpressing GsIMaT2 from G. soja on the soybean nodulation signaling system and strigolactone production was investigated. We discovered that the GsIMaT2 increased nodule numbers, fresh nodule weight, root weight, and root length by boosting strigolactone formation. Furthermore, we examined the isoflavone concentration of transgenic G. max hairy roots 10 and 20 days after rhizobial inoculation. Malonyldaidzin, malonylgenistin, daidzein, and glycitein levels were considerably higher in GsMaT2-OE hairy roots after 10- and 20-days of Bradyrhizobium japonicum infection compared to the control. These findings suggest that isoflavones and their biosynthetic genes play unique functions in the nodulation signaling system in G. max. Conclusions Finally, our results indicate the potential effects of the GsIMaT2 gene on soybean root growth and nodulation. This study provides novel insights for understanding the epistatic relationship between isoflavones, root development, and nodulation in soybean. Highlights * Cloning and Characterization of 7-O-beta-glucoside 6″-O-malonyltransferase (GsIMaT2) gene from wild soybean (G. soja). * The role of GsIMaT2 gene in the regulation of root nodule development. *Overexpression of GsMaT2 gene increases the accumulation of isoflavonoid in transgenic soybean hairy roots. * This gene could be used for metabolic engineering of useful isoflavonoid production.

Identification of hub genes regulating isoflavone accumulation in soybean seeds via GWAS and WGCNA approaches

“…( Nielsen and Williamson, 2007 ; Phetnoo et al., 2013 ), cardiovascular disease, osteoporosis, and metabolic syndrome ( Cai et al., 2004 ; Mozaffarian et al., 2011 ; Bradbury et al., 2014 ). In plants, isoflavones can resist adverse stress and promote the growth and reproduction of rhizobia, root nodule development, and nitrogen fixation ( Sugiyama et al., 2017 ; Darwish et al., 2022 ; Wang et al., 2022 ). Soybean seed isoflavones contain 12 components which are divided into four groups, daidzein, genistein, glycitein (aglycones), daidzin, glycitin, genistin (glycosides), acetyldaidzin, acetylglycitin, and acetylgenistin (acetylglycosides), and malonyldaidzin, malonylglycitin, malonylgenistin (malonylglycosides) ( Kim et al., 2014 ; Azam et al., 2021 ).…”

Methylated chalcones are required for rhizobial nod gene induction in the Medicago truncatula rhizosphere

“…Methylation could affect flavonoid bioactivity by improving membrane permeability, by enhancing their transport (either secretion by the plant and/or uptake by the rhizobia; Fang et al ., 2017), or by improved binding/activation of the NodD protein. In legumes flavonoid malonylation and glutathionation have been shown to be important for their transport across membranes and flavonoid malonylation was shown to promote nodulation (Li et al ., 1997; Zhao et al ., 2011; Ahmad et al ., 2021; Darwish et al ., 2022). In animal cells, improved intestinal absorption and persistence of methylated flavonoids were observed compared to their unmethylated counterparts, suggesting that methylation improves the bioavailability and stability of these compounds (Wen & Walle, 2006).…”

FlbZIP12 gene enhances drought tolerance via modulating flavonoid biosynthesis in Fagopyrum leptopodum

“…The relative expression levels were calculated by comparing the target genes’ cycle thresholds (CTs) with the reference gene FlH3 (the paralog of FtH3 , histone H3). Data quantifcation was carried out with the CFX Manager software using the 2 -ΔΔCt method ( Darwish et al., 2022 ). The primers used for RT-qPCR are listed in Table S1 .…”