Heat stress response in Chinese cabbage (Brassica rapa L.) revealed by transcriptome and physiological analysis

High temperatures have a serious impact on the quality and yield of cold-loving Chinese cabbage, which has evolved to have a unique set of stress mechanisms. To explore the relationship between these mechanisms and the heat-tolerance of Chinese cabbage, the physiological indicators of the heat-tolerant ???268??? line and heat-sensitive ???334??? line were measured. Under heat stress, the proline (Pro), soluble sugar (SS), and superoxide dismutase (SOD) indexes of the ???268??? line increased significantly. When additionally using transcriptome analysis, we found that the identified 3,360 DEGs were abundantly enriched in many metabolic pathways including ???plant hormone signal transduction???, ???carbon metabolism???, and ???glycolysis/ gluconeogenesis???. Dynamic gene expression patterns showed that HKL1 in Cluster 15 may be a key factor in the regulation of sugar homeostasis. The interaction network screened four ABA-related genes in Cluster 15, suggesting that high temperatures lead to changes in hormonal signaling, especially an increase in ABA signaling. Compared with the ???334??? line, the expressions of Prx50, Prx52, Prx54, SOD1, and SOD2 in the ???268??? line were significantly upregulated, and these genes were actively involved in the reactive oxygen species (ROS) scavenging process. In summary, our results revealed the relationship between plant heat tolerance, physiology, and biochemistry and may also provide ideas for the future development of high-quality and heat-tolerant Chinese cabbage germplasm resources.

Automated summary

This study examined the heat tolerance mechanisms and metabolic pathways in Chinese cabbage. The heat-tolerant line exhibited significant changes in physiological indicators and gene expression under heat stress. Additionally, hormone signaling and oxidative stress responses were found to play important roles in heat tolerance.