Trans-Zeatin and trans-Zeatin N-glucosides Regulate Cytokinin Signaling and Delay Salt-Induced Leaf Senescence in Arabidopsis thaliana

ABSTRACT: Plant productivity is adversely affected by exposure to abiotic stresses including salinity. Leaf tissue undergoes accelerated senescence with exposure to salt stress conditions, culminating in lowered efficiency of photosynthetic machinery. The N6-adenine derivative phytohormone Cytokinin (CK) is well known to delay natural leaf senescence by maintaining functioning photosynthesis processes. How various forms of CK function to control this activity and alter physiological and molecular responses under salt-induced leaf senescence is still not known. Here the CKs, trans-Zeatin (tZ) and its N-glucosylated (tZNGs) forms; tZ7G and tZ9G, were tested for their ability to delay leaf senescence in Arabidopsis thaliana. A modified dark-induced leaf senescence CK bioassay was used to study the physiology of photosynthesis performance as well as transcriptome and proteome level changes in detached leaves, across different phases of salt-induced leaf senescence from 2h-72h. Treatments with different CK forms (tZ, tZ7G, and tZ9G) showed that tZNGs can improve PSII efficiency (Fv/Fm) and increase chlorophyll levels compared to salt only treatments, indicating that these CK forms function as active CK forms in delaying senescence. At the transcript level, tZ, tZ7G, and tZ9G revealed differentially expressed genes (DEGs) across both developmental and salt-treated senescence, with tZNGs predominantly altering DEG in the terminal timepoint of salt-treated leaf senescence. Additionally, we found that tZNGs uniquely regulate crucial biological processes (BPs) including CK signaling compared to tZ. Proteome analysis showed that tZNGs and tZ showed similarities in number of differentially abundant proteins (DAPs) trends across senescence timepoints although each of the three forms showing uniquely abundant proteins. GO term analysis for tZNG regulated genes and proteins revel the enrichment of senescence- and chloroplast-related BPs. This study highlights the role of tZNGs as active cytokinin forms towards delaying salt-treated leaf senescence in Arabidopsis at the physiology, transcriptome, and proteome level.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Leaf

SUBMITTER: Martin Cerny  

LAB HEAD: Martin Cerny

PROVIDER: PXD048936 | Pride | 2025-06-01

REPOSITORIES: Pride