桃果实PpSIZ1基因对低温和外源褪黑素处理的响应

Expression Responses of SUMO E3 Ligase(SIZ1) to Low Temperature Stress and Exogenous Melatonin in Postharvest Peach Fruit

为了探索SUMO E3连接酶(SIZ1)基因与桃(Prunus persica L.Batsch)果实采后低温贮藏期间冷害发生的关系,对桃基因组中的SIZ1基因进行生物信息学分析,同时采用qRT-PCR分析该基因在‘湖景蜜露’桃果实低温贮藏以及外源褪黑素减轻冷害进程中的表达特征。结果表明,Pp SIZ1开放阅读框全长2 637 bp,编码878个氨基酸组成的蛋白质多肽。进化树分析发现,PpSIZ1与梅Pm SIZ1的同源性最高,含有与拟南芥At SIZ1相似的SAP、PHD、PINIT、SP-RING和SXS保守结构域,属于SUMO E3连接酶家族。q RT-PCR分析表明,低温(0℃)胁迫能诱导桃果实PpSIZ1表达水平的提高;100和200μmol·L^(-1)褪黑素处理能显著减轻桃果实低温贮藏期间冷害的发生,其中100μmol·L^(-1)褪黑素处理抑制冷害的效果最好,这种效果可能与PpSIZ1介导的SUMO化有关。

To explore the role of SUMO E3 ligase（SIZ1）gene in chilling injury incidence of postharvest peach fruit,Pp SIZ1 gene was identified and analyzed by bioinformatics.Furthermore,the effects of low temperature storage and exogenous melatonin treatments on Pp SIZ1 expression were investigated in＇Hujing Milu＇peach fruit during storage.Results showed that SIZ1 gene was identified in the peach genome and named as Pp SIZ1,and the ORF of Pp SIZ1 was 2 637 bp which encoded a predicted protein of 878 amino acids.Phylogenetic analysis indicated that Pp SIZ1 shared high similarity homology with Pm SIZ1.Bioinformatics analysis showed that Pp SIZ1 possessed predicted SAP,PHD,PINIT,SP-RING,and SXS domains,which were highly conserved in At SIZ1,indicated Pp SIZ1 could be classified with SUMO E3 Ligase.Chilling injury index of the fruit stored at 0 ℃increased with the prolongation of storage.Exogenous melatonin treatments（100 and 200 μmol·L^（-1））could significantly inhibited chilling injury incidence of peach fruit stored at 0 ℃,and 100 μmol·L^（-1） melatonin treatment exhibits the best inhibitory effect.Low temperature stress at 0 ℃ could induce the expression of Pp SIZ1,and the transcription level of Pp SIZ1 was strongly up-regulated when treated with 100 μmol·L^（-1）melatonin.These results suggest that PpSIZ1 protein possibly functioned as SUMO E3 ligase that facilitated the SUMO modification pathway,which could be associated with chilling tolerance in cold-stored peach fruit.