Comparative Physiological and Molecular Analyses of Two Contrasting Flue-Cured Tobacco Genotypes under Progressive Drought Stress.
Comparative Physiological and Molecular Analyses of Two Contrasting Flue-Cured Tobacco Genotypes under Progressive Drought Stress.
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两种烤烟基因型在干旱胁迫下的比较生理和分子分析
DOI：
10.3389/fpls.2017.00827
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发表时间：
2017
影响因子：
5.6
通讯作者：
Xia Z
中科院分区：
文献类型：
--
作者：
Su X;Wei F;Huo Y;Xia Z
干旱是限制作物生长和产量的主要环境因素。烤烟（Nicotiana tabacum）是世界上最重要的经济作物之一，其产量易受干旱影响。然而，长期干旱胁迫下，不同耐旱性烤烟品种的生理生化和基因表达变化的比较分析却很少。本研究从生理和转录水平比较研究了烤烟品种LJ851和JX6007对干旱胁迫的响应。在进行性干旱胁迫下，耐旱的LJ851表现出比干旱敏感的JX6007更小的生长抑制和叶绿素减少。与JX6007相比，LJ851在干旱胁迫后的抗氧化酶活性更高，H2O2、丙二醛（MDA）和电解质渗漏水平更低。进一步分析表明，LJ851在干旱胁迫下的净光合速率和气孔导度的下降幅度远小于JX6007，说明LJ851在干旱胁迫下的光合性能优于JX6007。此外，转录表达分析表明，LJ851表现出显着增加的几类干旱响应基因在干旱条件下的叶片和根的转录。这些结果表明，LJ851比JX6007更耐旱，表现为更好的光合性能，更强大的抗氧化系统，以及在干旱胁迫下更高的胁迫防御基因的表达。本研究为今后利用天然遗传变异培育耐旱烤烟新品种提供了重要参考。
Drought is a major environmental factor that limits crop growth and productivity. Flue-cured tobacco (Nicotiana tabacum) is one of the most important commercial crops worldwide and its productivity is vulnerable to drought. However, comparative analyses of physiological, biochemical and gene expression changes in flue-cured tobacco varieties differing in drought tolerance under long-term drought stress are scarce. In this study, drought stress responses of two flue-cured tobacco varieties, LJ851 and JX6007, were comparatively studied at the physiological and transcriptional levels. After exposing to progressive drought stress, the drought-tolerant LJ851 showed less growth inhibition and chlorophyll reduction than the drought-sensitive JX6007. Moreover, higher antioxidant enzyme activities and lower levels of H2O2, Malondialdehyde (MDA), and electrolyte leakage after drought stress were found in LJ851 when compared with JX6007. Further analysis showed that LJ851 plants had much less reductions than the JX6007 in the net photosynthesis rate and stomatal conductance during drought stress; indicating that LJ851 had better photosynthetic performance than JX6007 during drought. In addition, transcriptional expression analysis revealed that LJ851 exhibited significantly increased transcripts of several categories of drought-responsive genes in leaves and roots under drought conditions. Together, these results indicated that LJ851 was more drought-tolerant than JX6007 as evidenced by better photosynthetic performance, more powerful antioxidant system, and higher expression of stress defense genes during drought stress. This study will be valuable for the development of novel flue-cured tobacco varieties with improved drought tolerance by exploitation of natural genetic variations in the future.