Physiological and molecular mechanisms of leaf response to high-temperature stress in high-temperature-resistant soybean varieties

Abstract

Abstract Background With increasing global temperature, high temperature (HT) has become one of the main factors limiting soybean yield and quality. Exploring HT resistance-related functional genes and their corresponding molecular mechanisms is of great value. Previous physiological mechanism studies have shown that, compared with HD14 (HT sensitive), JD21 is an HT-resistant variety, and further analysis of the transcriptome and proteome has revealed the HT tolerance mechanism of JD21 anthers. Moreover, we found that compared with those of HD14 (28.72%), the leaves of JD21 also exhibited high HT resistance, and the degree of leaf wilting in JD21 plants after HT stress was 11.02%; however, the regulatory mechanism of the response of these plants to HT stress is still unclear. Results In this study, comparative transcriptome analysis of JD21 and HD14 soybean leaves after HT stress and field control plants was performed by RNA-seq technology. The results showed that the number of upregulated DEGs in JD21 and HD14 was greater than the number of downregulated DEGs after HT stress, and the number of up- or downregulated DEGs in JD21 was greater than that in HD14. Bioinformatics analysis revealed that many DEGs were involved in various molecular functions and metabolic pathways. QRT‒PCR analysis verified that the gene expression pattern determined via RNA–seq was reliable. In addition, through expression level and conserved domain analyses, 22 key candidate genes related to the response of soybean leaves to HT stress were screened. Conclusions The leaf gene expression networks of HT-resistant (JD21) and HT-sensitive (HD14) plants were constructed under HT stress and control conditions. Some DEGs responding to HT stress were screened through transcriptome sequencing. The GO annotations and KEGG pathways of these genes were analyzed to explore the regulatory mechanism of the response of soybean leaves to HT stress. Further through conserved domain analysis, several key candidate DEGs involved in the response to HT stress were identified. This study provides important data for further study of the molecular basis of the effect of HT on soybean leaves at the transcriptional level.