低温贮藏期间‘长富2’果实细胞壁酶及基因表达的变化

摘要

The ‘ Changfu 2’ cultivar was used to investigate the change of activity and gene expression of polygalacturonase (PG) and β-galactosidase (β-Gal),firmness,soluble solid content (SSC),titratable acidity and reducing sugar content during refrigerated storage (1-4 ℃).Results showed that firmness and titratable acidity decreased constantly and changed markedly,SSC and reducing sugar content increased slightly in the early storage and then decreased slowly.PG activity and expression of MdPG2 increased up to the peak in 120 d and expression of MdPGI reached the top in 60 d.The activity of β-Gal increased distinctly,having a negative correlation with changes of firmness.And expression of MdGAL1 and MdGAL2 increased before 60 d and decreased rapidly after 60 d.On the whole,gene expression of PG and β-Gal had significantly effects on enzyme activities because expression of PG and β-Gal genes was prior to increase of activities.%以‘长富2’苹果为实验材料,测定冷藏(1 ～4℃)期间果实多聚半乳糖醛酸酶(poly galacturonase,PG)、β3-半乳糖苷酶(β3-Gal)活性及基因表达变化,同时分析果实硬度、可溶性固形物(soluble solid content,SSC)、可滴定酸和还原糖含量.结果表明,果实的硬度和可滴定酸持续下降且变化显著;SSC和还原糖含量在贮藏前期有少量增加后缓慢下降;PG活性及MdPG1、MdPG2表达量均增加,PG活性和MdPG2表达量均在120 d达到峰值,MdPG1表达量在60 d达到最大值.β-Gal活性持续增加,与果实硬度呈显著负相关;MdGAL1和MdGAL2表达量在60 d之前增加,60 d以后迅速下降.总体上,PG和β-Gal基因表达先于酶活增加,对两种酶活性变化有重要作用.