不同处理对海沃德猕猴桃内源ABA相关代谢基因表达的影响

为在分子水平阐明外源乙烯利、1-MCP和ABA处理对海沃德猕猴桃内源ABA合成代谢的影响,并揭示ABA调控果实后熟机理。本研究以海沃德猕猴桃果实为试验材料,利用外源乙烯利、1-MCP和ABA处理猕猴桃果实,分别运用高相液相色谱(HPLC)和RT-qPCR分析20℃贮存条件下对猕猴桃内源ABA合成、信号通路相关基因XanDH、PYR/PYL、PP2C、ABF的表达量影响。结果表明,乙烯利处理下PP2C和ABF基因表达量在DAH17~DAH58都显著低于对照组,XanDH和PYR/PYL在DAH17均显著高于对照组,而后迅速回落。在ABA处理下XanDH基因表达量呈先下降后上升再下降的趋势,在DAH17表达量最高。PP2C和PYR/PYL在DAH17经历高峰后逐渐回落至低水平,与对照组差异显著。ABF在采后前期有较高的表达量,经历峰值后急速回落,在后熟中后期表达水平较低。1-MCP处理下,在整个后熟阶段,XanDH的表达量均显著高于对照组,在DAH17达到最大值,随后逐渐降落。与对照组相比,PP2C基因表达量持续上升,ABF基因持续下调;PYR/PYL在DAH17表达量最高而后下调,但仍显著高于对照组。表明乙烯利、1-MCP、ABA处理对海沃德猕猴桃内源ABA合成、信号传导有较大影响,本试验结果为进一步探究外源乙烯利、1-MCP和ABA对猕猴桃果实采后衰老的调控作用及机理提供了一定的理论依据。

Effects of Different Treatment on the Expression of Genes Involved in Endogenous Abscisic Acid in Hayward Kiwifruit

In order to investigate the effect of exogenous ethephon, ABA and 1-MCP on anabolism of endogenous ABA in Hayward kiwifruit and to reveal regulates mechanism of ABA on fruit ripening, exogenous ethephon, ABA and 1-MCP were applied on Hayward kiwifruits. HPLC and RT-qPCR were used to analyze the content change of ABA and the expression of genes relating to ABAs biosynthesis which including XanDH,PYR/PYL,PP2C and ABF in kiwifruit which stored at 20℃. This research provided a deeper insight into the ripening and aging mechanism regulated by ABA in kiwifruit. The results suggested that the samples treated with ethephon presented significantly lower expression of PP2C and ABF than the control group (P<0.01) from 17 days after harvest(DAH17) to DAH58, while the expression of XanDH and PYR/PYL in experimental group were significantly higher than those in control group on DAH17 and then decreased rapidly. In the group of ABA treatment, the expression of XanDH decreased first, then increased to the highest level on DAH17, after then the expression gradually decreased; the expression of PP2C and PYR/PYL reached the highest level on DAH17 and then decreased to a low level, which was significantly different from the control group; ABF had a higher expression level in the early period after harvest, while the expression decreased rapidly after the peak value, subsequently retained to a comparatively low expression in the late ripening phase. As for the samples exposed to 1-MCP, the expression of XanDH was significantly higher than that in control group throughout the experiment and a comparatively moderate decreasing trend was observed after the maximum on DAH17. Furthermore, compared with the control group, a steady increasing expression for PP2C and declining expression for ABF could be observed. Moreover, when the samples were treated with 1-MCP, PYR/PYL exhibited a significant higher expression than the untreated ones, even though PYR/PYL was down regulated after reaching the peak value on DAH17. As mentioned above, exogenous ethephon, 1-MCP and ABA could greatly influence biosynthesis of ABA and signal transduction in Hayward kiwifruit, which provide a novel access to clarifying the regulatory mechanism of the ripening and aging of Hayward kiwifrui by utilizing these three exogenous application.