Overaccumulation of glycine betaine enhances tolerance to drought and heat stress in wheat leaves in the protection of photosynthesis
Overaccumulation of glycine betaine enhances tolerance to drought and heat stress in wheat leaves in the protection of photosynthesis
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DOI：
10.1007/s11099-010-0016-5
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发表时间：
2010-05
期刊：
影响因子：
2.7
通讯作者：
G. -. Wang;X. Zhang;Feng Li;Y. Luo;Wei Wang
中科院分区：
文献类型：
--
作者：
G. -. Wang;X. Zhang;Feng Li;Y. Luo;Wei Wang
我们研究了小麦（Triticum aestivumL.）植物对干旱（DS）和热胁迫（HS）的不同反应，并分析了甘氨酸甜菜碱（GB）提高小麦对这些胁迫组合的耐受性的生理机制。转基因小麦 T6 系是通过将编码甜菜碱醛脱氢酶 (BADH) 的基因引入野生型 (WT) Shi4185 系中而产生的。该基因是从 Orache 植物 (Atriplex hortensisL.) 中克隆的。小麦幼苗遭受干旱胁迫（30%，PEG-6000）、热胁迫（40°C）及其组合。研究了不同胁迫下小麦叶片的光合气体交换、水分状况和脂质过氧化情况。当遭受干旱和高温的组合时，与单独的DS或HS相比，光合作用的抑制显着增加。联合胁迫对光合作用的抑制作用增强，不仅仅是单独的高温和干旱处理的加性胁迫效应；还发现植物生理学对 DS 和 HS 的不同反应。 HS比DS更能降低叶绿素（Chl）含量、净光合速率（PN）、羧化效率（CE）和表观量子产率（AQY），但DS比HS更能降低蒸腾速率（E）、气孔导度（gs）和细胞间CO2浓度（Ci）。 GB过度积累不仅在单独的DS或HS下而且在它们的组合下导致光合作用增加。抗氧化活性的增强和水分状况的改善可能是GB改善小麦植株光合作用的机制。
We investigated the different responses of wheat (Triticum aestivumL.) plants to drought- (DS) and heat stress (HS), and analyzed the physiological mechanisms of glycine betaine (GB) involved in the improvement of wheat tolerance to the combination of these stresses. The transgenic wheat T6 line was generated by introducing a gene encoding betaine aldehyde dehydrogenase (BADH) into the wild-type (WT) Shi4185 line. The gene was cloned from the Garden Orache plant (Atriplex hortensisL.). Wheat seedlings were subjected to drought stress (30%, PEG-6000), heat stress (40°C), and their combination. Photosynthetic gas exchange, water status and lipid peroxidation of wheat leaves were examined under different stresses. When subjected to a combination of drought and heat, the inhibition of photosynthesis was significantly increased compared to that under DS or HS alone. The increased inhibition of photosynthesis by the combined stresses was not simply the additive stress effect of separate heat- and drought treatments; different responses in plant physiology to DS and HS were also found. HS decreased the chlorophyll (Chl) content, net photosynthetic rate (PN), carboxylation efficiency (CE) and apparent quantum yield (AQY) more than DS but DS decreased the transpiration rate (E), stomata conductance (gs) and intercellular CO2concentration (Ci) more than HS. GB over-accumulation led to increased photosynthesis not only under individual DS or HS but also under their combination. The enhancement of antioxidant activity and the improvement of water status may be the mechanisms underlying the improvement of photosynthesis by GB in wheat plants.