Table_3_iTRAQ Proteomic Analysis of Wheat (Triticum aestivum L.) Genotypes Differing in Waterlogging Tolerance.DOCX

Transient and chronic waterlogging constrains crop production in many regions of the world. Here, we invoke a novel iTRAQ-based proteomic strategy to elicit protein synthesis and regulation responses to waterlogging in tolerant (XM 55) and sensitive genotypes (YM 158). Of the 7,710 proteins identified, 16 were distinct between the two genotypes under waterlogging, partially defining a proteomic basis for waterlogging tolerance (and sensitivity). We found that 11 proteins were up-regulated and 5 proteins were down-regulated; the former included an Fe-S cluster assembly factor, heat shock cognate 70, GTP-binding protein SAR1A-like and CBS domain-containing protein. Down-regulated proteins contained photosystem II reaction center protein H, carotenoid 9, 10 (9′, 10′)-cleavage dioxygenase-like, psbP-like protein 1 and mitochondrial ATPase inhibitor. We showed that nine proteins responded to waterlogging with non-cultivar specificity: these included 3-isopropylmalate dehydratase large subunit, solanesyl-diphosphate synthase 2, DEAD-box ATP-dependent RNA helicase 3, and 3 predicted or uncharacterized proteins. Sixteen of the 28 selected proteins showed consistent expression patterns between mRNA and protein levels. We conclude that waterlogging stress may redirect protein synthesis, reduce chlorophyll synthesis and enzyme abundance involved in photorespiration, thus influencing synthesis of other metabolic enzymes. Collectively, these factors accelerate the accumulation of harmful metabolites in leaves in waterlogging-susceptible genotypes. The differentially expressed proteins enumerated here could be used as biological markers for enhancing waterlogging tolerance as part of future crop breeding programs.

短时与长期渍涝胁迫在全球诸多区域均制约作物生产。本研究采用基于iTRAQ的新型蛋白质组学策略，解析耐渍基因型XM 55与渍敏基因型YM 158在渍涝胁迫下的蛋白质合成与调控响应。在鉴定得到的7710个蛋白质中，渍涝胁迫下两个基因型间存在16个差异显著的蛋白质，部分阐明了渍涝耐性（及敏感性）的蛋白质组学基础。研究发现，11个蛋白质呈上调表达，5个呈下调表达：上调蛋白包括铁硫簇组装因子、热激同源蛋白70、GTP结合蛋白SAR1A样蛋白以及含CBS结构域的蛋白质。下调蛋白则包含光系统II反应中心蛋白H、类胡萝卜素9,10(9',10')-裂解双加氧酶样蛋白、psbP样蛋白1以及线粒体ATP酶抑制剂。本研究还发现，9个蛋白质对渍涝胁迫的响应不存在品种特异性，其中包括3-异丙基苹果酸脱水酶大亚基、茄尼基二磷酸合酶2、DEAD盒ATP依赖RNA解旋酶3以及3个预测蛋白或未表征蛋白。在选取的28个蛋白质中，有16个在mRNA与蛋白质水平上呈现一致的表达模式。本研究认为，渍涝胁迫可能会重定向蛋白质合成过程，降低叶绿素合成及光呼吸相关酶的丰度，进而影响其他代谢酶的合成。综上，这些因素会加速渍敏基因型植株叶片中有害代谢物的积累。本研究鉴定得到的差异表达蛋白可作为生物标志物，用于未来作物育种中提升品种的渍涝耐性。