低温贮藏对猕猴桃果实成熟软化相关基因表达影响

为探究低温对果实采后成熟软化与淀粉降解的影响,以红阳猕猴桃果实为试验材料,研究在低温贮藏期间,猕猴桃果实硬度,可溶性固形物、乙烯、淀粉含量以及淀粉酶相关基因的变化。结果表明,低温贮藏能显著抑制猕猴桃果实采后成熟软化,延缓果实淀粉的降解和可溶性固形物含量的增加,维持贮藏期间果实较高的硬度。低温贮藏抑制乙烯合成关键基因AcACO1和AcACS1的表达,抑制乙烯合成。同时,低温贮藏显著抑制淀粉降解相关基因AcAMY1、AcBAM1/3、AcISA3、AcLDA1和AcDPE1的表达。在低温贮藏后期,淀粉酶相关基因AcAMY1、AcBAM1/3、AcLDA1和AcDPE1的表达与乙烯释放速率有关。综上,低温贮藏延缓猕猴桃采后成熟软化进程与淀粉降解密切相关,可能主要通过抑制乙烯合成,从而影响贮藏后期淀粉降解速率,最终延缓果实软化进程。本研究结果为猕猴桃采后低温贮藏提供了理论依据。

Effects of Low Temperature Storage on the Expression of Genes Involved in Maturation and Softening of Kiwifruit Fruits

In order to investigate the effects of low temperature on ripening, softening and starch degradation of postharvest fruits, the changes of fruit firmness, soluble solids, ethylene, starch content and starch enzyme related genes during low temperature storage in Hongyang kiwifruit (Actinidia chinesis) were investigated. The results showed that low temperature could significantly inhibit the ripening and softening of kiwifruit fruit after harvest, delay the degradation of starch, increase the content of soluble solids, and maintain the high hardness of the fruit during storage. Low temperature also inhibited the expressions of AcACO1 and AcACS1 and ethylene synthesis. In addition, low temperature decreased the expression of the starch degradation related genes AcAMY1, AcBAM1/3, AcISA3, AcLDA1, AcDPE1. In the late stage of cryopreservation, the expression of amylase-related genes AcAMY1, AcBAM1/3, AcLDA1 and AcDPE1 was related to the amount of ethylene released. These results suggest that, low temperature delaying the postharvest ripening and softening process of kiwifruit is closely related to starch degradation, which may affect the ethylene degradation by inhibiting ethylene synthesis, and ultimately delayed the fruit softening process. These results provide a theoretical basis for postharvest storage of kiwifruit.