摘要
【目的】对桃基因组中的PpGAD和PpPAO进行生物信息学分析,研究外源5 mmol·L-1γ-氨基丁酸(γ-aminobutyric acid,GABA)处理对桃果肉0℃贮藏期间内源多胺(PAs)和GABA含量及其合成代谢关键基因(PpADC、PpODC、PpPAO和PpGAD)表达的影响。【方法】应用Ex PASy进行PpGAD和PpPAO蛋白基本理化性质分析,采用Gene Doc和MEGA软件对桃基因组中的PpGAD和PpPAO进行生物信息学分析,采用荧光定量PCR对相关基因表达进行q RTPCR检测。【结果】PpGAD属于稳定亲水性蛋白,而PpPAO属于不稳定亲水性蛋白,环状结构均占较高比例。PpGAD和PpPAO均与苹果同源性最高,可能为直系同源蛋白。适宜浓度的GABA处理(5 mmol·L-1)通过上调桃果实中PpADC和PpODC的表达量,促进了腐胺(Put)的合成。外源GABA处理抑制了PpPAO的表达,缓解了果实低温贮藏期间精胺(Spm)和亚精胺(Spd)的降解;同时外源GABA处理上调了PpGAD的表达,促进了内源GABA的合成。【结论】外源5 mmol·L-1GABA处理可维持低温胁迫下桃果实中较高水平的内源多胺和GABA含量,增强了果实抵抗低温胁迫的能力。
【Objective】Peach fruit is highly sensitive to chilling injury（CI）. CI symptoms in peach fruit seriously reduce commercial fruit quality and consumer acceptance. γ-aminobutyric acid（GABA） is suggested to act as an important role in postharvest fruit in response to cold stress. To explore the role of PpGAD and PpPAO in chilling tolerance regulation of peach fruit after harvest by GABA, PpGAD and PpPAO in peach genome were identified, and their bioinformatics was analyzed. Additionally, the effect of the exogenous 5 mmol·L-1GABA treatment on gene expression of PpADC, PpODC, PpPAO and PpGAD,which are involved in polyamines（PAs） and GABA biosynthesis and metabolism, in postharvest peach fruit stored at 0 ℃ was investigated.【Methods】Ex PASy was employed to analyze the basically physical and chemical properties of PpGAD and PpPAO genes, and Gene Doc and MEGA were used to predict their functions. Total RNA was extracted from the mesocarp of peach fruit using Plant Total RNA Extraction Kit according to the manufacturer＇s protocol. Its quality and quantity were assessed by agarose gel electrophoresis. Then total RNA was reverse-transcribed to synthesis the first-strand c DNA. The expres-sion of related genes was detected by using fluorescence quantitative PCR. With the c DNA as a template,real-time PCR amplification reaction was performed using Dy NAmo Flash SYBR Green PCR kit. Cycle threshold（Ct） numbers were recorded for both the reference and target genes, and calculated relative to a calibrator using the formula 2–ΔΔCt. GABA content was determined by lanthanum chloride extraction method, 1 mol ·L-1KOH, borate buffer（p H 9.0）, 6%phenol and 5%sodium hypochlorite were successively added to the solution extracted,after boiled water bath for 10 min and iced bath for 5min, 60% ethanol was added immediately,and absorbance was measured at 645 nm using a Shimadzu UV-1750 spectrophotometer. Polyamine contents were measured by adopting pre-column benzoyl chloride derivatization combining wit
出处
《果树学报》
CAS
CSCD
北大核心
2016年第5期552-562,共11页
Journal of Fruit Science
基金
国家自然科学基金(31371866)
浙江省自然科学基金(LQ15C200004)
宁波市自然科学基金(2015A610262)
关键词
桃果实
多胺
Γ-氨基丁酸
低温胁迫
Peach fruit
Polyamine
γ-aminobutyric acid
Low temperature stress
