茉莉酸甲酯处理对鲜切甜瓜贮藏期间苯丙烷代谢的影响

Effect of Methyl Jasmonate Treatment on Phenylpropanoid Pathway in Fresh-cut Melon during Storage

茉莉酸甲酯(methyl jasmonate,MeJA)是一种天然存在的内源物质和信号分子,在植物胁迫应激反应和生长发育过程中起到调节作用。以“西州蜜-17”甜瓜为试材,采用100μmol/L MeJA 20℃熏蒸20 h,研究其对鲜切甜瓜贮藏期间总酚含量和苯丙烷代谢途径关键酶活性和基因表达水平的影响。结果表明:切分前MeJA处理能够显著提高贮藏期间鲜切甜瓜总酚含量,增加苯丙氨酸解氨酶(phenylalanine ammonia-lyase,PAL)、肉桂酸4-羟化酶(cinnamate 4-hydroxylase,C4H)和4-香豆酸-CoA连接酶(4-coumarate:CoA ligase,4CL)活性,同时还发现MeJA处理提高了贮藏期间鲜切甜瓜CmPAL1/2/3、CmPAL5-9、CmC4H1/2/4和Cm4CL1/2的表达量(P<0.05)。由此表明,切分前MeJA处理能提高贮藏期间鲜切甜瓜苯丙烷代谢的水平,诱导酚类物质的积累。

Methyl jasmonate(MeJA),as a natural endogenous substance and a signal molecule,plays an important role in stress response and development in plant.The effect of MeJA fumigation(100μmol/L,treatment at 20℃for 20 h)on phenylpropanoid pathway during storage of'Xizhoumi-17'melon was assayed in this study.Results showed that MeJA treatment significantly increased the total phenolics content,and enhanced the activities of phenylalanine ammonia-lyase(PAL),cinnamate 4-hydroxylase(C4H)and 4-coumarate:CoA ligase(4CL)(P<0.05).In addition,the expression of CmPAL1/2/3,CmPAL5-9,CmC4H1/2/4,and Cm4CL1/2 was also upregulated by MeJA treatment(P<0.05).Taken together,these results imply that MeJA treatment of fresh-cut melon would elevate the phenylpropanoid pathway and lead to the accumulation of phenolics.