黄肉桃中PpSGRs对蓝光的响应及其对贮藏中类胡萝卜素积累的影响

PpSGRs Responsed to Blue Light and Affect Carotenoids Accumulation in Postharvest Yellow-flesh Peach Fruit

为揭示蓝光处理促进黄肉桃果实类胡萝卜素积累的机制,以黄肉桃‘金丽’果实为研究对象,从桃基因组中筛选出PpSGR1和PpSGRL基因进行生物信息学分析,并通过q-PCR分析PpSGR1和PpSGRL在不同组织和不同发育阶段果实及其在40μmol·m^(-2)·s^(-1)蓝光处理果实中的表达。结果表明,PpSGR1具有多半胱氨酸保守域,属于SGR亚族;PpSGRL基因C端突变失去多半胱氨酸保守域,属于SGR-Like亚族;PpSGR1和PpSGRL都含有叶绿体信号肽,与梅亲缘关系最近。PpSGRs在‘金丽’桃不同组织和不同成熟阶段果实中均有表达,其中PpSGR1与果实采后类胡萝卜素的合成密切相关。蓝光处理可快速抑制桃果实PpPIF3进而抑制PpSGR1的转录,促进贮藏前期果实中PpPSY的表达,提高类胡萝卜素的合成和积累。同时,蓝光处理可能通过促进桃果实内源乙烯合成,上调PpSGR1表达进而抑制PpPSY转录水平,降低桃果实贮藏后期类胡萝卜素的合成能力。

In order to explore the mechanism of blue light promoting carotenoids accumulation in postharvest peaches（‘Jinli＇,yellow-flesh）,PpSGR1 and PpSGRL were identified based on peach genome and analyzed by bioinformatics. Furthermore,the expression profile of PpSGR1 and PpSGRL in different tissues and developmental fruits and the effects of blue light treatment（40 μmol · m^（-2） · s^（-1）） on PpSGR1 and PpSGRL expression were investigated in‘Jinli＇peach fruit during storage. Results showed that PpSGR1 possessed cysteine-rich motif and belonged to STAY GREEN subfamily,while PpSGRL belonged to STAY GREEN-like subfamily due to the mutation of cysteine-rich motif in C-terminal. PpSGR1 and PpSGRL both contained a chloroplast transit peptide in their N-terminal,and shared high similarity homology with Prunus mume. Expression pattern of PpSGR1 and PpSGRL differed significantly in peach tissues and developmental fruit,especially the expression of PpSGR1 was closely related to carotenoids accumulation in peach fruit. Blue light treatment suppressed PpPIF3 and resulted in a rapid depression of PpSGR1 expression,but up-regulated the transcription level of PpPSY,and promoted carotenoids accumulation in postharvest peaches during first 6 days storage. Meanwhile,blue light promoted ethylene production in postharvest peaches which up-regulated expression of PpSGR1,and resulted in the PpPSY repression and carotenoids accumulation.