The Arabidopsis thaliana trehalose-6-phosphate phosphatase gene AtTPPI improve chilling tolerance through accumulating soluble sugar and JA

As a non-reducing disaccharide, trehalose functions as a protective compound against adverse conditions. Our previous studies indicated that the Arabidopsis thaliana trehalose-6-phosphate phosphatase gene AtTPPI is crucial for improving plant water use efficiency (WUE) and drought tolerance. In the present study, we further demonstrated that AtTTPI participates in resistance to chilling stress. The results showed that tppi1 mutants were sensitive to chilling stress, while overexpression plants were tolerant. CBF1, CBF2 and CBF3 could directly regulate the expression of AtTPPI, and the expression of AtTPPI was inhibited in the cbf1, 2, 3 triple mutants under chilling stress, which indicates that CBF1, CBF2 and CBF3 could regulate the expression of AtTPPI under chilling stress. Further analysis of transcriptome data showed that jasmonic acid (JA) signaling pathway genes accounted for the majority of genes involved in this response. The content of JA in the overexpression plants was higher than that in wild type (WT) under both control and chilling treatment conditions, and the JA content in the tppi1 mutant was the lowest. This suggested that the AtTPPI gene may directly mediate JA synthesis. Increased AtTPPI expression enhanced the content of soluble sugars and Tre6P levels specifically under chilling stress, indicating that AtTPPI may function together with soluble sugars and Tre6P in response to chilling stress. These findings suggest a possible role of AtTPPI in regulating JA accumulation and soluble sugar levels under chilling stress and provide a genetic engineering strategy to improve plant chilling tolerance.