革叶猕猴桃休眠过程中生理变化与转录组分析

Physiological changes and transcriptome analysis of Actinidia rubricaulis var. coriacea during dormancy

关键词:  革叶猕猴桃, 需冷量, 休眠解除, 转录组分析, 激素调控

Key words:  Actinidia rubricaulis var. coriacea, chilling requirement, dormancy release, transcriptome analysis, hormone regulation

摘要:

该研究以革叶猕猴桃(Actinidia rubricaulis var. coriacea)为研究对象,通过系统测定需冷量,结合生理生化测定与高通量转录组测序技术,解析了其从休眠起始至解除过程中芽体内部碳水化合物代谢、内源激素平衡及抗氧化酶系统的动态变化规律。结果表明:(1)随着低温积累,至休眠解除阶段,芽体可溶性糖含量明显增加(约为初始阶段的2倍),而淀粉含量明显降低(约下降至最初水平的一半),表明碳水化合物代谢呈现淀粉降解与可溶性糖积累的动态转换。(2)内源激素水平呈现阶段性变化,脱落酸(ABA)含量从起始阶段的486.75 μg·L^-1显著下降至休眠解除阶段的218.45 μg·L^-1,赤霉素(GA)含量从214.23 pg·mL^-1明显上升至614.75 pg·mL^-1,ABA/GA比值从2.27降至0.36,表明激素平衡向促进萌发方向转变。(3)抗氧化酶系统(SOD、POD等)活性在低温积累192 h时达到峰值,表明芽体通过增强抗氧化能力来应对低温胁迫。(4)转录组分析鉴定出12 685个差异表达基因(DEGs),其中6 067个基因表达上调,6 618个基因表达下调,富集于植物激素信号转导、淀粉与蔗糖代谢和环境应答等通路,揭示了多基因协同调控机制。该研究首次在系统水平上阐明革叶猕猴桃需冷量积累的生理-转录协同调控机制,为应对气候变暖导致的休眠障碍及育种的相关研究奠定基础。

Abstract:

This study selected Actinidia rubricaulis var. coriacea as the research subject, systematically measuring chilling requirements and integrating physiological-biochemical assays with high-throughput transcriptome sequencing to elucidate dynamic changes in bud carbohydrate metabolism, endogenous hormone balance, and antioxidant enzyme systems during the process from the dormancy initiation to the dormancy release. The results were as follows:(1)With chilling accumulation, bud soluble sugar content significantly increased(approximately two fold of initial stage)while starch content markedly decreased(to about half of initial level)by dormancy release, indicating a dynamic metabolic shift from starch degradation to soluble sugar accumulation.(2)Endogenous hormone levels exhibited stage-specific changes, with abscisic acid(ABA)content decreasing from 486.75 μg·L^-1 at initial stage to 218.45 μg·L^-1 at dormancy release stage, and gibberellin(GA)content increasing from 214.23 pg·mL^-1 to 614.75 pg·mL^-1, resulting in an ABA/GA ratio decline from 2.27 to 0.36, suggesting a hormonal shift toward germination promotion.(3)Antioxidant enzyme system(SOD, POD, etc.)activities peaked at 192 h of chilling accumulation, indicating enhanced antioxidant capacity as a response to cold stress.(4)Transcriptome analysis identified 12 685 differentially expressed genes(DEGs), with 6 067 genes up-regulated and 6 618 genes down-regulated, enriched in plant hormone signal transduction, starch and sucrose metabolism, and environmental response pathways, revealing a multi-gene coordinated regulatory mechanism. This work, for the first time at the systems level, elucidates the physiological-transcriptomic coordinated regulatory mechanism of chilling requirement accumulation in A. rubricaulis var. coriacea, providing a foundation for addressing climate warming-induced dormancy disorders and related breeding research.