Metabolomics and Transcriptomic Analysis Revealed the Response Mechanism of Maize to Saline-Alkali Stress

Chunlai Wang, Xiaotong Wei, Yimeng Wang, Chenyang Wu, Peng Jiao, Zhenzhong Jiang, Siyan Liu, Yiyong Ma, Shuyan Guan

Plant Biotechnol J.; 2025 Aug 15. doi: 10.1111/pbi.70292.

Abstract

Saline-alkali stress inhibited the normal growth and development of plants, which seriously restricted the yield of crops. Maize is one of the most important crops in the world. However, the mechanism of maize in response to saline-alkali stress is still largely unknown. Through the observation of growth parameters and the detection of physiological and biochemical indicators in saline-alkali tolerant (22KN3894) and saline-alkali sensitive (H23146) maize inbred lines, this study found that compared with H23146, 22KN3894 accumulated less ROS content and more total flavonoids content, while the degree of root damage and ion toxicity was relatively small. Full-length transcriptome and broadly targeted metabolome were used to analyse the response mechanism of extreme maize inbred lines to saline-alkali stress. 22KN3894 accumulated more metabolites such as sugars and flavonoids. There were significant differences in the contents of flavonoid metabolites and genes related to flavonoid synthesis between the two materials. Weighted gene co-expression network analysis and co-expression network analysis based on RNA-Seq data suggested that the ZmWRKY82 gene might respond to saline-alkali stress by regulating the flavonoid biosynthesis pathway. ZmWRKY82 directly bound to the W-box in the ZmCHI6 promoter and promoted its expression. The above results showed that ZmWRKY82 could improve the antioxidant capacity by promoting the transcription of ZmCHI6 and the synthesis of flavonoids, thereby resisting saline-alkali stress. These findings provided novel insights for improving maize saline-alkali stress tolerance, demonstrating that flavonoids played pivotal roles in plant stress adaptation, and laid the foundation for future mechanistic studies and breeding improvement.

See: https://pubmed.ncbi.nlm.nih.gov/40815574/

Figure 1: Effects of saline-alkali stress on phenotype and physiological and biochemical indexes of maize inbred lines. (A) Phenotypic changes of maize inbred lines KN3894 and H146. Scale bar = 5 cm. (B–D) Activity of antioxidant enzymes, SOD, POD, and CAT. (E) MDA content. (F) Relative Electrolyte Leakage. (G) Relative water content. (H) Na⁺ content. (I) K⁺ content. (J) Ca²⁺ content. (K) Na⁺/K⁺ ratio. (L) Flavonoids content. Asterisks indicate a significant difference between CK and SA of the same material; while ns indicate no significant difference (*p < 0.05, **p < 0.01). CK, control; SA, saline-alkali stress. H146, H23146; KN3894, 22KN3894.