桃漆酶基因家族鉴定及其与冷害褐变的关系

Identification of laccase gene family members in peach and its relationship with chilling induced browning

摘要:

为研究桃果实漆酶(PpLAC) 基因家族成员的功能，利用生物信息分析方法对桃果实LAC基因成员进行鉴定，分析不同品种桃果实低温贮藏和外源γ-氨基丁酸(γ-aminobutyric acid，GABA) 处理下的表达模式及其与冷害褐变的关系，为桃果实抗冷害褐变机制提供理论依据。研究从桃果实基因组筛选了26个漆酶基因，这些漆酶基因分布于6条染色体上，含有5–7个外显子，基因结构和保守基序较为相似。根据聚类分析结果将桃果实PpLAC基因家族成员分为7个亚族。通过良方水蜜桃、湖景水蜜桃以及外源GABA处理组的转录组测序结果分析，发现PpLAC7、PpLAC9在低温贮藏下表达量呈上升模式，且与褐变指数呈现相同的趋势。GABA处理组减轻桃果实褐变程度，且PpLAC7、PpLAC9的表达也被抑制，推测PpLAC7、PpLAC9可能与桃果实冷害褐变有关。

Abstract:

The laccase (PpLAC) gene family members in peach fruit were identified and the relationship between their expression pattern and chilling induced browning were investigated. The study was performed using two varieties of peaches with different chilling tolerance, treated with or without exogenous γ-aminobutyric acid (GABA) during cold storage. Twenty-six genes were screened from the peach fruit genome. These genes were distributed on 6 chromosomes and each contained 5–7 exons. The PpLAC gene family members shared relatively similar gene structure and conserved motifs, and they were classified into 7 subgroups based on the cluster analysis. Transcriptome sequencing revealed that the expression levels of PpLAC7 and PpLAC9 exhibited an increasing pattern under low temperature storage, and displayed a similar trend with the browning index of peach fruit. Notably, GABA treatment reduced the degree of browning and inhibited the expression of PpLAC7 and PpLAC9. These results suggested that PpLAC7 and PpLAC9 might be involved in the browning of peach fruit during cold storage.