Division of Plant Physiology and Biochemistry, ICAR-Indian Institute of Sugarcane Research, Lucknow, India.
Amity Institute of Biotechnology, Amity University, Lucknow, India.
Plant Biol (Stuttg). 2019 Jan;21(1):45-53. doi: 10.1111/plb.12919. Epub 2018 Oct 27.
Drought is one of the most serious environmental factors limiting production of sugarcane worldwide. In order to assess the influence of gibberellins (GA ) on drought and plant growth, along with associated physio-biochemical attributes, expression of eight drought-responsive genes were quantified and analysed. At grand growth stage (120 DAP) two sugarcane varieties (CoLk94184, CoPK05191) were exposed to drought by withholding irrigation. GA (35 ppm) was applied using battery-operated uniform controlled dispensing sprayer twice at 1-week intervals on 2-week drought-stressed plants. Physio-biochemical attributes including antioxidant enzyme activities were estimated following standard protocols. RT-PCR was performed to visualise the drought-associated gene expression patterns. Drought triggered a reduction in RWC and chlorophyll content but these recovered when droughted plants were exposed to GA . Proline content increased many fold in both varieties under stress, but decreased under the influence of GA . There was a mixed response of antioxidant enzyme activity, which distinctly declined after GA exposure, together with a lesser reduction in dry matter content over that of control plants. With increasing stress, expression of pyrroline-5-carboxylase synthetase (P5CS) and betaine-aldehyde dehydrogenase genes was observed, selectively up-regulated in CoPK05191. Expression of proline oxidase/transporter was high in CoPK05191 but diminished along with proline content after exposure to GA CoLk94184 showed no significant difference in P5CS gene expression under stress condition, whereas expression of betaine-aldehyde dehydrogenase gene was unchanged in response to stress. Results demonstrated that exposure of droughted plants to GA not only led to recovery of activity of drought-associated physio-biochemical attributes, but also minimised impact on cane dry weight and quality. Further, GA application caused differential gene expression that possibly triggers increased responsiveness towards drought tolerance in sugarcane.
干旱是全球限制甘蔗生产的最严重环境因素之一。为了评估赤霉素（GA）对干旱和植物生长的影响，以及相关的生理生化特性，对 8 个干旱响应基因的表达进行了定量和分析。在大生长阶段（120 DAP），通过停止灌溉使两种甘蔗品种（CoLk94184、CoPK05191）遭受干旱。在 2 周干旱胁迫的植物上，使用电池驱动的均匀控制分配喷雾器每 1 周喷施两次 GA（35ppm）。根据标准方案估算生理生化特性，包括抗氧化酶活性。进行 RT-PCR 以可视化与干旱相关的基因表达模式。干旱导致 RWC 和叶绿素含量降低，但在将干旱植物暴露于 GA 时，这些含量会恢复。脯氨酸含量在胁迫下在两种品种中均增加了数倍，但在 GA 的影响下减少。抗氧化酶活性的反应混合，在 GA 暴露后明显下降，与对照植物相比，干物质含量的减少较少。随着胁迫的增加，观察到吡咯啉-5-羧酸合成酶（P5CS）和甜菜醛脱氢酶基因的表达，在 CoPK05191 中选择性地上调。脯氨酸氧化酶/转运蛋白在 CoPK05191 中的表达较高，但在暴露于 GA 后与脯氨酸含量一起减少。CoLk94184 在胁迫条件下 P5CS 基因表达没有显着差异，而甜菜醛脱氢酶基因的表达对胁迫没有变化。结果表明，将干旱植物暴露于 GA 不仅导致与干旱相关的生理生化特性的活性恢复，而且还最大程度地减少了对甘蔗干重和质量的影响。此外，GA 处理引起了差异基因表达，这可能引发甘蔗对干旱胁迫的响应性增加。
