期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2021
卷号：118
期号：48
DOI：10.1073/pnas.2105021118
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
The regulatory roles of cytokinin (CK) signaling on metabolic plasticity of plant response to salt stress remain widely unknown. A comprehensive metabolome and transcriptome analysis of CK-signaling–defective
Arabidopsis thaliana histidine-containing phosphotransfer protein ahp2,3,5 and type-B
Arabidopsis response regulator arr1,10,12 triple mutants under nonsaline and saline conditions revealed that CK signaling induces a reprogramming of gene-to-metabolite networks involved in
Arabidopsis response to salinity. CK signaling modulates prestress and poststress accumulations of sugars, amino acids, and anthocyanins as well as membrane lipid reprogramming as an emerging mechanism of salinity adaptation in
Arabidopsis. Our results provide insights into CK-signaling–mediated regulation of gene-to-metabolite networks in response to salt stress, enabling the efficient application of CK biology in stress tolerance-oriented plant biotechnology.
Cytokinin (CK) in plants regulates both developmental processes and adaptation to environmental stresses.
Arabidopsis histidine phosphotransfer ahp2,3,5 and type-B
Arabidopsis response regulator arr1,10,12 triple mutants are almost completely defective in CK signaling, and the
ahp2,3,5 mutant was reported to be salt tolerant. Here, we demonstrate that the
arr1,10,12 mutant is also more tolerant to salt stress than wild-type (WT) plants. A comprehensive metabolite profiling coupled with transcriptome analysis of the
ahp2,3,5 and
arr1,10,12 mutants was conducted to elucidate the salt tolerance mechanisms mediated by CK signaling. Numerous primary (e.g., sugars, amino acids, and lipids) and secondary (e.g., flavonoids and sterols) metabolites accumulated in these mutants under nonsaline and saline conditions, suggesting that both prestress and poststress accumulations of stress-related metabolites contribute to improved salt tolerance in CK-signaling mutants. Specifically, the levels of sugars (e.g., trehalose and galactinol), amino acids (e.g., branched-chain amino acids and γ-aminobutyric acid), anthocyanins, sterols, and unsaturated triacylglycerols were higher in the mutant plants than in WT plants. Notably, the reprograming of flavonoid and lipid pools was highly coordinated and concomitant with the changes in transcriptional levels, indicating that these metabolic pathways are transcriptionally regulated by CK signaling. The discovery of the regulatory role of CK signaling on membrane lipid reprogramming provides a greater understanding of CK-mediated salt tolerance in plants. This knowledge will contribute to the development of salt-tolerant crops with the ability to withstand salinity as a key driver to ensure global food security in the era of climate crisis.
关键词：cytokinin signaling; comparative metabolomics; comparative transcriptomics; regulatory network; salt stress
