Differential Role for Trehalose Metabolism in Salt-Stressed Maize
Differential Role for Trehalose Metabolism in Salt-Stressed Maize
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DOI：
10.1104/pp.15.00729
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发表时间：
2015-10-01
期刊：
影响因子：
7.4
通讯作者：
Lagrimini, L. Mark
中科院分区：
文献类型：
--
作者：
Henry, Clemence;Bledsoe, Samuel W.;Lagrimini, L. Mark
关于盐如何影响 C-4 植物的主要代谢途径，特别是与籽粒发育和结籽有关的代谢途径，人们知之甚少。从花器官萌芽到授粉后3天，通过用增加浓度的氯化钠灌溉对玉米（Zea mays）B73施加渗透胁迫。在吐丝时，光合作用仅减少至对照植物的 2%。研究发现盐处理会减少小穗生长、穗丝生长和籽粒凝固。渗透胁迫导致吐丝、授粉和授粉后 3 天时叶、穗轴和籽粒中蔗糖 (Suc) 和己糖浓度较高。柠檬酸循环中间体在盐处理的组织中较低，表明这些糖不能用于呼吸。由于盐处理，糖信号代谢物海藻糖 6-磷酸在抽丝时在叶、穗轴和籽粒中升高，但此后即使 Suc 水平继续升高，糖信号代谢物海藻糖 6-磷酸盐也降低。有趣的是，叶组织中海藻糖途径基因的转录受盐处理的影响最大。另一方面，蔗糖非发酵相关激酶 1 (SnRK1) 标记基因的转录本在生殖组织中受影响最大。总体而言，盐降低了源和库的强度，并且数据表明海藻糖-6-磷酸和SnRK1可能在源和库组织中具有不同的作用。渗透压导致的籽粒败育并非由于缺乏碳水化合物储备，而是由于无法利用这些能量储备。
Little is known about how salt impacts primary metabolic pathways of C-4 plants, particularly related to kernel development and seed set. Osmotic stress was applied to maize (Zea mays) B73 by irrigation with increasing concentrations of NaCl from the initiation of floral organs until 3 d after pollination. At silking, photosynthesis was reduced to only 2% of control plants. Salt treatment was found to reduce spikelet growth, silk growth, and kernel set. Osmotic stress resulted in higher concentrations of sucrose (Suc) and hexose sugars in leaf, cob, and kernels at silking, pollination, and 3 d after pollination. Citric acid cycle intermediates were lower in salt-treated tissues, indicating that these sugars were unavailable for use in respiration. The sugar-signaling metabolite trehalose-6-phosphate was elevated in leaf, cob, and kernels at silking as a consequence of salt treatment but decreased thereafter even as Suc levels continued to rise. Interestingly, the transcripts of trehalose pathway genes were most affected by salt treatment in leaf tissue. On the other hand, transcripts of the SUCROSE NONFERMENTING-RELATED KINASE1 (SnRK1) marker genes were most affected in reproductive tissue. Overall, both source and sink strength are reduced by salt, and the data indicate that trehalose-6-phosphate and SnRK1 may have different roles in source and sink tissues. Kernel abortion resulting from osmotic stress is not from a lack of carbohydrate reserves but from the inability to utilize these energy reserves.