Hg-Responsive Proteins Identified in Wheat Seedlings Using iTRAQ Analysis and the Role of ABA in Hg Stress

Wheat
seedlings exposed to 100 μM HgCl2 for 3
days exhibited high-level mercury (Hg) accumulation, which led to
inhibited growth, increased lipid peroxidation, and disrupted cellular
ultrastructures. And root growth and ultrastructural changes of wheat
seedlings were inhibited more severely than those of leaves. To identify
the wheat protein response to Hg stress, the iTRAQ method was used
to determine the proteome profiles of the roots and leaves of wheat
seedlings exposed to high-Hg conditions. 249 proteins were identified
with significantly altered abundance. 117 were found in roots and
132 in leaves. These proteins were classified into signal transduction,
stress defense, carbohydrate metabolism, protein metabolism, energy
production, and transport functional groups. The majority of proteins
identified in Hg-stressed roots and leaves displayed differently altered
abundance, revealing organ-specific differences in adaption to Hg
stress. Pathway Studio software was used to identify the Hg-responsive
protein interaction network that included 49 putative key proteins,
and they were potentially regulated by abscisic acid (ABA). Exogenous
ABA application conferred protection against Hg stress and increased
activities of peroxidase enzyme, suggesting that it may be an important
factor in the Hg signaling pathway. These findings can provide useful
insights into the molecular mechanisms of Hg responses in higher plants.

小麦幼苗在100 μM 汞氯化物（HgCl2）的暴露下，经过3天的处理，表现出高水平的汞（Hg）积累，这导致了生长抑制、脂质过氧化增加以及细胞超微结构的破坏。相较于叶片，小麦幼苗的根生长和超微结构变化受到的影响更为严重。为了识别小麦对汞胁迫的蛋白质反应，本研究采用iTRAQ方法测定了在汞高暴露条件下小麦幼苗根和叶部的蛋白质组谱。共鉴定出249种蛋白质其丰度发生了显著变化，其中117种存在于根部，132种存在于叶片。这些蛋白质被归类为信号转导、胁迫防御、碳水化合物代谢、蛋白质代谢、能量产生和运输等功能组。在汞胁迫的根部和叶片中，鉴定出的多数蛋白质丰度变化存在差异，揭示了器官在适应汞胁迫过程中的特异性差异。通过Pathway Studio软件，识别出了汞响应的蛋白质相互作用网络，其中包括49种假定的关键蛋白质，这些蛋白质可能受到脱落酸（ABA）的调控。外源ABA的应用提供了对汞胁迫的保护作用，并增加了过氧化物酶酶活性，这表明它可能是汞信号通路中的一个重要因素。这些发现可为深入了解高等植物汞响应的分子机制提供有价值的见解。