基于iTRAQ技术的不同耐旱性甘薯苗期根系差异蛋白分析

为从蛋白水平揭示不同甘薯品种的苗期耐旱性差异,明确甘薯耐旱性生理机制,以耐旱性强的济薯21(JS)和耐旱性弱的济紫薯1(JH)为材料,采用PEG-6000模拟田间梯度干旱胁迫过程,采用i TRAQ技术开展甘薯苗期根系全蛋白组差异蛋白分析。结果表明,在4个比较组中,共筛选到567个差异表达蛋白,其中上调表达蛋白302个,覆盖率达20%以上的蛋白占鉴定总蛋白数的58.6%。GO分析发现,JS苗期根系差异蛋白主要集中在胁迫响应、非生物刺激响应等生物过程,而JH苗期根系差异蛋白主要集中在糖基复合物代谢和辅酶代谢等生物过程,干旱均主要影响2个品种的细胞质、细胞溶质等细胞组分,2个品种的差异蛋白分子功能均涉及催化活性、氧化还原酶活性等方面。KEGG分析发现,正常条件下,耐旱性强的较耐旱性弱的甘薯品种苗期根系中的过氧化物酶(POD)和肉桂醇脱氢酶(CAD)表达上调;在干旱条件下,次生代谢合成过程中的苯丙烷合成通路中上调表达的差异蛋白最多,耐旱性强的JS苗期根系中主要是胁迫响应相关蛋白,而耐旱性弱的JH苗期根系中主要是能量代谢相关蛋白。总之,干旱对甘薯苗期根系细胞质中次生物质合成和能量代谢影响较大,耐旱性强的甘薯苗期根系氧化还原酶类蛋白表达上调,不同耐旱性甘薯苗期根系在蛋白组学水平上响应干旱的生理调控途径存在明显差异。本研究为甘薯耐旱性品种生理鉴定和耐旱基因发掘提供了线索。

Analysis of Differential Proteome in Roots During Seedling Stage of Sweetpotato With Different Drought Tolerance Based on iTRAQ Method

In order to reveal the drought tolerance difference in seedling stage of sweetpotato from protein level,and to explicit the mechanism of drought tolerance,Jishu21 (JS) with strong drought tolerance and Jizishu1 (JH) with weak drought tolerance were chosen as research material.Dimensional electrophoresis and mass spectrometry were used to reveal differential expression proteins in seedling roots treated by hydroponic PEG-6000 to simulate a gradient drought stress in the field.As a result,total 567 differential expressed proteins were screened out in four comparable groups,and 302 differential proteins were up-regulated.The percentage of the protein which exceeds 20％ coverage was 58.6％ of the total protein number.GO analysis showed that differential proteins of JS in seedling stage were mainly focused on stress and abiotic stimulus response process,however,glycosyl compound metabolic and coenzyme metabolic process are involved in JH.Drought mainly affected the cytoplasm and cytosol of both varieties,and the molecular function of differential proteins are all refer to catalytic and oxidoreductase activity.Compared to the variety with weak drought tolerance,POD and CAD were up-regulated in roots of variety with strong drought tolerance in seedling stage under normal condition.Under drought treatment,the up-regulated differential proteins are mostly involved in phenylpropanoid biosynthesis pathway.Stress response proteins were mainly presented in seedling roots of JS,while energy metabolic proteins were mainly presented in JH.In one word,biosynthesis of secondary metabolism and energy metabolic process were greatly affected by drought in cytoplasm of sweetpotato roots in seedling stage,and oxidoreductase expression level was up-regulated in JS with strong drought tolerance.Physiological regulation ways responded to drought between sweetpotato with different drought tolerance in proteomic level were significantly different.The study can provide clues for physiological identification of drought tolerance sweetpotato and exploration of tolerance related genes.