Physiological and transcriptomic analysis reveals the coating of microcapsules embedded with bacteria can enhance wheat salt tolerance.

Abstract

Salt stress is one of the most important abiotic stress factors limiting crop production. Therefore, improving the stress resistance of seeds is very important for crop growth. Our previous studies have shown that using microcapsules encapsulating bacteria (Pontibacter actiniarum DSM 19842) as seed coating for wheat can alleviate salt stress. In this study, the genes and pathways involved in the response of wheat to salt stress were researched further. The results showed that compared with the control, the coating can improve osmotic stress and decrease oxidative damage by increasing the content of proline (29.1%), the activity of superoxide dismutase (SOD) (94.2%), peroxidase (POD) (45.7%) and catalase (CAT) (3.3%), reducing the content of hydrogen peroxide (H₂O₂) (39.8%) and malondialdehyde (MDA) (45.9%). In addition, ribonucleic acid (RNA) sequencing data showed that 7628 differentially expressed genes (DEGs) were identified, and 4426 DEGs up-regulated, 3202 down-regulated in the coated treatment. Many DEGs related to antioxidant enzymes were up-regulated, indicating that coating can promote the expression of antioxidant enzyme-related genes and alleviate oxidative damage under salt stress. The differential gene expression analysis demonstrated up-regulation of 27 genes and down-regulation of 20 genes. Transcription factor families, mostly belonging to bHLH, MYB, B3, NAC, and WRKY. Overall, this seed coating can promote the development of sustainable agriculture in saline soil.