5-氨基乙酰丙酸对苹果幼果多酚含量、苯丙氨酸解氨酶活性及其基因表达的影响

Effect of 5-Aminolevulinic Acid on Polyphenol Content, PAL Activity and PAL Gene Expression in Young Apple Fruits

探究5-氨基乙酰丙酸(aminolevulinic acid,ALA)处理对苹果幼果酚类物质、苯丙氨酸解氨酶(phenylalanin ammonia-lyase,PAL)活性及其基因表达量的影响。在苹果疏果期前,利用不同质量浓度ALA处理苹果幼果,采用紫外分光光度法测定ALA处理后12 d内苹果多酚和PAL活性,利用荧光定量法测定苹果幼果PAL基因表达量。结果表明:ALA处理质量浓度在300 mg/L以内,随着质量浓度提高,苹果多酚含量、PAL酶活性及其基因表达量均升高,到400 mg/L时各项指标均表现出下降趋势;相同质量浓度ALA处理苹果幼果后,幼果的上述3项指标均随时间延长而明显提高,在第9天时达到最高值,12 d后开始下降。为提高苹果疏果多酚含量,实现疏果的最大利用率,生产中需要选择适宜的ALA处理浓度和时间采集幼果。

The purpose of this study was to find out the effect of 5-aminolevulinic acid(ALA) application on phenolic substances and phenylalanine ammonia lyase(PAL) activity and PAL gene expression in young apple fruits. Apple fruits were treated with various concentrations of ALA before thinning, and then over a subsequent period of 12 days, total phenolic contents and PAL activity were measured by UV spectrophotometry and the expression of PAL gene by fluorescent quantitative real-time polymerase chain reaction(RT-qPCR). The experiment results indicated that as the ALA concentration increased up to 300 mg/L, the PAL activity, total phenolic content and PAL gene expression levels all showed an increasing trend, while the opposite pattern was observed for these three parameters when the ALA concentration was further raised to 400 mg/L. At identical ALA concentrations, all these parameters became significantly higher with prolonged treatment time, reaching the maximum levels on the 9th day, and began to fall on the 12th day. Thus, it can be concluded that treatment of young apple fruits with ALA at concentrations around 300 mg/L may result in a variety of desired physiological changes, such as markedly increasing phenolic substances and improving the activity level and gene expression of PAL.