Physiological and transcriptomic analyses reveal the mechanisms underlying the salt tolerance of Zoysia japonica Steud.
Abstract Soil salinization areas are sparsely populated and have fragile ecosystems, which seriously restricts the sustainable development of local economies. Zoysia grasses are recognized as excellent warm-season turfgrasses worldwide, with high salt tolerance and superior growth in saline-alkali soil. However, the mechanism underlying the salt tolerance of Zoysia remains unknown. In our study, we investigated the phenotypic and physiological responses of two contrasting materials, Zoysia japonica Steud. Z004 (salt sensitive) and Z011 (salt tolerant), to salt stress. The results showed that Z011 exhibited stronger salt tolerance than Z004, with a higher K + /Na + ratio in both its leaves and roots. To further study the molecular mechanisms underlying salt tolerance, we compared the transcriptomes of the two materials at different time points (0 h, 1 h, 24 h, and 72 h) and from different tissues (leaves and roots) under salt treatment. The 24-h time point and roots were identified as the significant time point and tissue. According to the GO and KEGG analyses of different comparisons, the key DEGs participating in the salt-stress response were selected and belonged to the hormone pathway, TF families and the DUF family. The interaction between the key DEGs was discussed, revealing that auxin signal transduction and TF families may cooperate in Zoysia salt tolerance and that the WRKY family may be the most important TF family. Thus, our research provides fundamental information regarding the salt-stress response in Zoysia and enhances the understanding of molecular mechanisms in salt-tolerant plants.