褪黑素调控水杨酸和乙烯代谢维持沙果贮藏品质

Melatonin Regulates Salicylic Acid and Ethylene Metabolism to Maintain Shaguo Quality During Storage

为探究褪黑素(melatonin melatonin,MT)处理对沙果(Malus asiatica Nakai)成熟调控因子乙烯和水杨酸代谢及贮藏品质的影响,以沙果为试验材料,设置MT浸泡处理,并以蒸馏水浸泡为对照,利用实时荧光定量PCR研究乙烯及水杨酸合成关键酶基因表达水平,并测定其在贮藏期间的生理生化变化。结果表明,MT处理显著上调了MdPAL和MdICS2这2个与水杨酸合成相关基因的表达量,与水杨酸含量变化趋势一致。贮藏14 d时,MT处理组沙果果实中水杨酸含量达0.84 mg·kg^(-1),显著诱导了果实中水杨酸的合成。MT处理使得贮藏期间沙果果实中乙烯合成关键基因MdACO1和MdACS1表达水平受到抑制,这与乙烯释放受到显著抑制的结果一致。贮藏28 d时,MT处理组沙果果实硬度较对照组提高了34.60%,有效缓解了沙果果实硬度的下降和失重率的上升,抑制了呼吸作用。综上,褪黑素可以通过抑制乙烯生物合成代谢和提高水杨酸累积代谢来延缓沙果果实品质劣变。本研究结果为维持果实采后品质提供了技术参考。

In order to explore the effects of melatonin(MT)treatment on ethylene and salicylic acid(SA)metabolism,as well as the storage quality of shaguo(Malus asiatica Nakai),shaguo was soaked with MT,and the control group was soaked with distilled water.The gene expression levels of key enzymes for ethylene and SA synthesis were studied by real time fluorescent quantitative PCR,and the physiological and biochemical changes of shaguo during storage were measured.The results showed that MT treatment significantly increased the expression of MdPAL and MdICS2,which was consistent with the trend of SA content in shaguo.The content of SA after stored for 14 days reached 0.84 mg·kg^(-1),which induced the synthesis of SA in the shaguo.Furthermore,the expression levels of MdACO1 and MdACS1 were inhibited,which was consistent with the inhibition of ethylene production.The firmness of MT-treated shaguo increased by 34.60%compared with the control after 28 days of storage,which effectively alleviated the decline of fruit firmness and the increase of weight loss,and inhibited respiration.To summarize,MT effectively inhibited the deterioration of fruit quality during storage by increasing the accumulation and metabolism of salicylic acid and inhibiting ethylene biosynthesis.The results provide a reference for the application of maintaining the quality of fruits.