基于转录组分析云南山茶内源激素对干旱胁迫及复水的响应.

【Objective】The paper aims to explore the effect of drought stress on endogenous hormones in Camellia reticulata and the molecular mechanism of plant hormone signal transduction pathway responding to drought stress.【Method】The pot seedlings of half-one-year-old wild C.reticulata were used as experimental materials, and 20% PEG-6000 was used to simulate severe drought stress. The contents of auxin (IAA), zeatin nucleoside (ZR), gibberellin (GA) and abscisic acid (ABA) in roots and leaves of C.reticulata at 0, 24, 72 hours and 48 hours after rewater (re48 hours) under drought stress, and at the same time, the leaves were sequenced by transcriptome to screen differential genes.【Result】Under drought stress, the endogenous hormones in C.reticulata were all affected. The IAA content in leaves first increased and then decreased and then increased after rehydration, while the IAA content in roots continued to decrease and did not recover after rewater. The change trend of ZR content in leaves was the same as IAA, while that in roots was opposite to that in leaves.GA content in leaves increased continuously during stress and rewater, while GA content in roots increased during stress and decreased after rewater. The change trend of ABA content in leaves was similar to IAA, and ABA content in roots continued to increase during stress, and then decreased after rewater, which was similar to the change trend of GA content in roots.A total of 33 349 differentially expressed genes were screened from the transcriptome sequencing results of C.reticulata, which were significantly enriched in plant hormone transduction, phenylpropionic acid biosynthesis, carotenoid biosynthesis, porphyrin and chlorophyll metabolism, photosynthesis and other pathways at four time points. Drought stress induced the expression of 46 differential genes in plant hormone signal transduction pathway. Four gene modules were identified by weighted gene co-expression network analysis (WGCNA), and the transcription group was correlated with the contents of the four hormones. Two key gene modules with high correlation with hormone response were screened, including 2769 and 2502 genes respectively. The top 5% genes in the key modules were selected for co-expression analysis, and six key genes (SDH1-1, PETC, VHA-A3, FtsH, chlD, TL17) and five transcription factors (IAA9, NAC, Trihelix, SWI/SNF, NF-YB) were obtained.【Conclusion】Drought stress affects the changes of endogenous hormone content and the expression of related pathway genes. In the study, two co-expression modules closely related to drought stress response are also identified. It is found that genes such as SDH1-1, PETC, VHA-A3, FtsH, chlD, TL17 and transcription factors such as IAA9, NAC, Trihelix, SWI/SNF, NF-YB play an important role in the response of endogenous hormones in C.reticulata under drought stress. [ABSTRACT FROM AUTHOR]