Correlation network analysis of abiotic stressrelated genes reveals the coordinated regulation of transcription in Chinese cabbage

Plant responses to abiotic stresses such as drought, cold, and salt stress include altered expression of genes involved in metabolic processes, including growth, development, and physiological changes. Non-biological stress can lead to changes in the growth and morphology of crops, as well as reduced harvest volume. Plants must respond simultaneously to multiple stresses in the environment; therefore, research on abiotic stress should focus on the interactions of these stress responses. In the present study, we constructed a co-expression network for multidirectional analysis of cold, drought, and salt stress response genes in Chinese cabbage (Brassica rapa L. ssp. pekinensis). We constructed the co-expression network using abiotic stress-related data from the KBGP-24K microarray in the B. rapa Expressed sequence tag data and microarray database (BrEMD) and performed abiotic-stress specific gene expression analyses of B. rapa. The core mechanism underlying abiotic stress tolerance in B. rapa is the inactivation of abscisic acid metabolism, which triggers proline biosynthesis. We also characterized unknown genes possibly related to abiotic stress tolerance by producing transgenic Chinese cabbage lines overexpressing these genes.