Comparative Analysis Highlights Uniconazole's Efficacy in Enhancing the Cold Stress Tolerance of Mung Beans by Targeting Photosynthetic Pathways

Abstract

Soybean (Glycine max) and mung bean (Vigna radiata) are key legumes with global importance, but their mechanisms for coping with cold stress-a major challenge in agriculture-have not been thoroughly investigated, especially in a comparative study. This research aimed to fill this gap by examining how these two major legumes respond differently to cold stress and exploring the role of uniconazole, a potential stress mitigator. Our comprehensive approach involved transcriptomic and metabolomic analyses, revealing distinct responses between soybean and mung bean under cold stress conditions. Notably, uniconazole was found to significantly enhance cold tolerance in mung bean by upregulating genes associated with photosynthesis, while its impact on soybean was either negligible or adverse. To further understand the molecular interactions, we utilized advanced machine learning algorithms for protein structure prediction, focusing on photosynthetic pathways. This enabled us to identify LOC106780309 as a direct binding target for uniconazole, confirmed through isothermal titration calorimetry. This research establishes a new comparative approach to explore how soybean and mung bean adapt to cold stress, offers key insights to improve the hardiness of legumes against environmental challenges, and contributes to sustainable agricultural practices and food security.

Keywords: cold stress; mung bean; soybean; uniconazole.

Figure 1

Workflow overview and comparative analysis of metabolome and transcriptome. (A) Transcriptomic and metabolic analysis schematic. (B) Quantitative overview of differentially expressed genes in soybean and mung bean. (C) Volcano plot highlighting up-regulated (in red) and down-regulated (in green) metabolites. (D) Venn diagram illustrating the overlap and differences in gene expression between various treatments in soybean and mung bean. CK represents the control group sprayed with water and planted under normal temperature, LT represents the group sprayed with distilled water and planted under low temperature, LT + S represents the group sprayed with uniconazole S3307 and planted under low temperature.

Figure 2

Principal component analysis (PCA) of soybean and mung bean response to various treatments. (A) PCA analysis of soybean transcriptomic profiles. (B) PCA analysis of mung bean transcriptomic profiles. (C) PCA analysis of metabolome expression profiles in soybeans and mung beans. CK represents a control group treated neither with chemical treatment nor cold stress, LT represents the group treated with cold stress without uniconazole S3307, and LT + S represents the group treated with uniconazole S3307 followed by cold stress.

Figure 3

Impact of uniconazole on photosynthesis. Physiological analysis under different treatments: (A) net photosynthetic rate (Pn), (B) transpiration rate (Tr), (C) intracellular CO₂ (Ci), (D) stomatal conductance, (E) total chlorophyll content, (F) RT-qPCR expression levels of CHUP1 and WRI1 Genes. CK represents a control group treated neither with chemical treatment nor cold stress, CK + uniconazole represents a group treated with uniconazole S3307 under normal temperature, LT represents a group treated with cold stress without uniconazole S3307, and LT + uniconazole represents a group treated with uniconazole S3307 followed by cold stress. Different letters on the bar chart indicate significant differences among treatments (p < 0.05, Duncan’s multiple range test).

Figure 4

Comparative analysis of genetic variations and phylogeny in Asian beans. (A) INDEL events in soybean, (B) INDEL events in mung bean, (C) SNP occurrences in soybean, and (D) SNP occurrences in mung bean. The red arrows in Figure 4C,D point to the location where there is a significant difference in SNP density between soybean and mung bean.

Figure 5

Interactive transcriptomic and metabolomic analysis in mung bean. (A) and (B) Pearson correlation test of top 20 metabolites and transcripts under different treatments. The sugar-related metabolites are underlined with red color in panel A. (C) KGML network analysis under low-temperature stress and uniconazole treatment with RT-qPCR validation of GPDH expression. CK represents a control group treated neither with chemical treatment nor cold stress, LT represents a group treated with cold stress without uniconazole S3307, and LT + uniconazole represents a group treated with uniconazole S3307 followed by cold stress. Different letters on the bar chart indicate significant differences among treatments (p < 0.05, Duncan’s multiple range test).

Figure 6

Assessment of uniconazole binding to photosynthesis-related genes. (A) Docking scores for uniconazole across photosynthesis-enriched gene sites. (B) Predicted binding site of uniconazole on LOC106777957. (C) Protein purification of LOC106777957. (D) Isothermal titration calorimetry (ITC) analysis of recombinant LOC106777957 interaction with uniconazole.

Figure 7

Comparative analysis of soybean and mung bean responses to uniconazole treatment under low-temperature stress conditions.