西瓜幼苗根系发育过程中的蛋白质组分析

Proteomic analysis on root growth and development of watermelon seedlings

[目的]通过对西瓜幼苗根系不同发育时期的蛋白质组变化的研究,从蛋白质表达水平上来揭示西瓜幼苗根系发育的分子机制。[方法]采用双向电泳技术对西瓜根系不同时期的蛋白质组进行比较,对差异蛋白质点进行图谱分析和MALDITOF/TOF质谱鉴定,采用荧光定量PCR技术(RT-q PCR)对候选蛋白基因进行表达验证。[结果]共得到12个差异表达蛋白质点,12个差异蛋白表现不同的表达趋势,其中上调表达4个,下调表达2个,不规则表达6个。经质谱分析,11个蛋白得到鉴定,对鉴定出的蛋白进行功能分析,其中10个蛋白分别涉及蛋白质生物合成(20%)、代谢相关(40%)、防御应答(30%)和GA信号途径(10%),1个为功能未知蛋白。4个候选蛋白基因的RT-q PCR分析结果显示,茉莉酸诱导蛋白1和抗坏血酸过氧化物酶基因在mRNA水平的表达变化与蛋白水平一致,而赤霉素受体基因GID1L2和茉莉酸诱导蛋白2基因的表达可能与转录后调控有关。[结论]本文揭示了西瓜幼苗根系发育蛋白质组的表达特征,获得了在西瓜根系发育过程中可能有重要功能的蛋白,为深入开展西瓜根系生长发育相关基因功能研究提供了数据资源。

[Objectives]To understand the function of differentially expressed proteins in roots of watermelon seedlings,proteins of watermelon roots at different developmental stages were studied using proteomics technique. This work will provide a theoretical basis for further studying on the molecular mechanism of watermelon root development. [Methods]A comparative study of watermelon roots at different developmental stages was carried out by using two-dimensional gel electrophoresis. The differentially expressed protein spots identified by electrophoresis were further analyzed by MALDI-TOF/TOF. Expression profiles of candidate protein genes were investigated using quantitative real time PCR（RT-qPCR）. [Results]Twelve differentially expressed protein spots were identified by electrophoresis. Levels of 12 proteins were differential,of which,4 proteins were up-regulated,2 proteins were down-regulated and 6 proteins were differentially-regulated. 11 protein spots were finally identified by MALDI-TOF/TOF. Functions of these 11 proteins were analyzed which included 10 functional proteins involved in protein biosynthesis（20%）,metabolism（40%）,plant defense（30%）and GA signaling（10%）,and 1 unknown protein. Four candidate protein genes were further investigated using RT-qPCR. Expression changes of jasmonate-induced protein 1 gene and ascorbate peroxidase gene in mRNA level were consistent with those in proteomic levels,while the expression of gibberellin receptor gene GID1L2 and Jasmonate-induced protein 2 gene might be related with transcriptional regulation. [Conclusions]This work gives a global insight into the characteristics of proteome of watermelon roots at different developmental stages by using two-dimensional gel electrophoresis. Proteins with important function were acquired which might be valuable resources for future research.