Photosynthetic enzyme activities and gene expression associated with drought tolerance and post-drought recovery in Kentucky bluegrass
Photosynthetic enzyme activities and gene expression associated with drought tolerance and post-drought recovery in Kentucky bluegrass
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DOI：
10.1016/j.envexpbot.2012.12.001
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发表时间：
2013-05
影响因子：
5.7
通讯作者：
Lixin Xu;J. Yu;Liebao Han;Bingru Huang
中科院分区：
文献类型：
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作者：
Lixin Xu;J. Yu;Liebao Han;Bingru Huang
维持活跃的光合作用对于植物适应干旱胁迫是重要的。本研究的目的是确定主要的光合作用因素与遗传变异的耐旱性和干旱后的恢复能力的多年生禾本科植物，肯塔基州早熟禾（Poa pratensis），通过研究差异光合反应和潜在的酶活性，以及基因表达在干旱胁迫和复水的耐旱性对比。两个品种（'午夜'和'辉煌'）的植物暴露于10天的干旱胁迫，随后在生长室中复水3天。通过对草坪质量、相对含水量和电解质渗漏率的生理分析，证实了“午夜”具有上级耐旱性和干旱后的恢复能力。耐旱品种Midnight在10 d干旱胁迫期间和复水后均保持了较高的净光合速率（Pn）、较高的1，5-二磷酸核酮糖羧化酶（Rubisco）活性和转录水平、较高的磷酸甘油醛脱氢酶（GADH）活性以及复水后较高的Rubisco活化状态。这两个品种没有不同的酶活性或基因转录水平的磷酸核酮糖激酶在干旱胁迫或复水。这些结果表明，Rubisco控制的羧化和GAPDH调控的碳还原可能是草地早熟禾光合作用遗传变异的关键代谢过程，而活性Rubisco、GAPDH和Rubisco活化酶均参与肯塔基州早熟禾干旱后的恢复。
Maintaining active photosynthesis is important for plant adaptation to drought stress. The objective of this study was to determine major photosynthetic factors associated with genetic variability governing drought tolerance and post-drought recuperative ability of a perennial grass species, Kentucky bluegrass (Poa pratensis), by examining differential photosynthetic responses and underlying enzyme activities as well as gene expression during drought stress and re-watering for two cultivars contrasting in drought tolerance. Plants of two cultivars (‘Midnight’ and ‘Brilliant’) were exposed to 10d drought stress and subsequently re-watered for 3d in growth chambers. Physiological analysis via turf quality, relative water content, and electrolyte leakage confirmed that ‘Midnight’ exhibits superior drought tolerance and post-drought recuperative ability. Drought-tolerant ‘Midnight’ maintained significantly higher net photosynthetic rate (Pn), higher enzymatic activity and transcript level of ribulose-1,5-bisphosphate carboxylase (Rubisco), higher enzymatic activity of glyceraldehyde phosphate dehydrogenase (GADPH) during 10-d drought stress and in responses to re-watering, as well as higher Rubisco activation state upon re-watering. The two cultivars did not differ with regard to enzymatic activity or gene transcript level of phosphoribulokinase during drought stress or upon re-watering. These results suggest that carboxylation controlled by Rubisco and carbon reduction regulated by GAPDH could be the key metabolic processes imparting genetic variation in Pnresponses to drought stress while active Rubisco, GAPDH and Rubisco activase could all be involved in the superior post-drought recovery in Kentucky bluegrass.