Ha, B.-K. | bioRxiv Science

bioRxiv2025

Loss of flavonol 3-O-glucosyltransferase activity confers soybean resistance to leaf-chewing insects

Caterpillars and beetles are among the most economically damaging defoliating insects, and their economic damage is predicted to increase in the coming decades. Hence the use of genetically derived resistance to supplement other pest control strategies is warranted. In soybean (Glycine max (L.) Merr.), a major determinant for resistance is the quantitative trait locus, QTL-M. Glyma07g14530, the gene underlying QTL-M, encodes a feeding-inducible flavonol 3-O-glycosyltransferase (F3GlcT or UGT78D2) that glucosylates kaempferol, as well as quercetin, myricetin, and isorhamnetin. The resistant allele has a premature stop codon in it, thus preventing the glucosylation and sequestration of flavonols in the vacuole, leading to a concomitant accumulation of proanthocyanidins and manifestation of resistance. Expressing the dominant (susceptible) allele in resistant plants restores susceptibility and silencing the susceptible allele results in resistance. The discovery and characterization of GmF3GlcT helps clarify the role of flavonoids in resistance to leaf-chewing insects and facilitates the development of insect-resistant cultivars that ultimately can lower production costs and reduce insecticide applications. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=131 SRC="FIGDIR/small/679769v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@10e2e77org.highwire.dtl.DTLVardef@ca905org.highwire.dtl.DTLVardef@12cb46corg.highwire.dtl.DTLVardef@1f9328b_HPS_FORMAT_FIGEXP M_FIG C_FIG The loss of flavonol 3-O-glucosyltransferase in soybean reduces feeding damage from defoliating insects and is accompanied by a concomitant increase in proanthocyanidins (red arrowhead). SignificanceUnraveling the biochemical and genetic basis of soybean resistance to leaf-chewing insects facilitates the development of new, naturally insect resistant varieties. Such varieties contribute to on-farm profitability and reduced concerns over pesticide residues in the field.

plant biology↗

bioRxiv2021

Change in protein, oil and fatty acid contents in soybeans (Glycine max (L.) Merr.) of different seed coat colors and seed weight

Soybean seeds are one of the best sources of plant-based high-quality proteins and oils. The contents of these metabolites are affected by both environmental and genetic factors. In this study, 49 soybean germplasms were cultivated in Korea, the contents of total protein, total oil and five fatty acids were determined, and the influences of seed coat color and seed weight on each were assessed. The total protein and total oil contents were evaluated using Kjeldahl and Soxhlet methods and were in the ranges of 36.28-44.19% and 13.45-19.20%, respectively. Moreover, the contents of individual fatty acids were determined as area percentage from acquired gas-chromatography peaks. The contents of palmitic, stearic, oleic, linoleic and linolenic acids were in the ranges of 9.90-12.55, 2.45-4.00, 14.97-38.74, 43.22-60.26, and 5.37-12.33%, respectively and each significantly varied between the soybean germplasms. Unlike total oil and fatty acid contents, total protein content was not significantly affected by both seed coat color and seed weight. Cluster analysis grouped the soybeans into two classes with notable content differences. Fatty acids were the main factors for the variabilities seen between the soybean germplasms as observed in the principal component analysis. Correlation analysis revealed a significant but negative association between total oil and total protein contents (r = -0.714, p < 0.0001). Besides, a trade-off relationship was observed between oleic acid and linoleic acid (r = -0.936, p < 0.0001) which was reflected with respect to both seed coat color and seed weight. Among all colored soybeans, pale-yellow soybeans had the highest and the lowest levels of oleic acid and linoleic acid, respectively each being significantly different from the rest of colored soybeans (p < 0.05). Likewise, oleic acid content increased with seed weight while that of linoleic acid decreased with seed weight (p < 0.05). In general, this study showed the significance of seed coat color and seed weight to discriminate soybean genotypes, mainly in terms of their fatty acid contents. Moreover, the soybean germplasms with distinct characters and fatty acid contents identified in this study could be important genetic resources for cultivar development.

plant biology↗