Sugarcane (Saccharum spp. hybrid) contributes to 80% of world sugar production and is a valuable source of biomass for the production of lignocellulosic ethanol making it an important commercial crop. Drought stress is one of the major abiotic stress factors which reduces the productivity and quality of sugarcane. Increase in the intensity and duration of drought coupled with the rising demand of sugar warrants the development of drought-tolerant sugarcane. Genetic engineering offers potential strategies to develop superior sugarcane varieties that improve crop productivity in drought-prone environments. Thus, with a view to develop drought-tolerant sugarcane, in the present study, an expansin gene which confers drought tolerance, was transformed into sugarcane. An expansin gene (EaEXPA1) from Erianthus arundinaceus, a wild relative of sugarcane, was overexpressed in the commercial sugarcane variety Co 86032 through Agrobacterium-mediated transformation. Transgenic lines exhibited significantly higher level of EaEXPA1 expression over the control plants. The performance evaluation of V₁ transgenics under the drought stress revealed significantly higher relative water content, cell membrane thermostability, chlorophyll content, photosynthetic efficiency (Fv/Fm) and gas-exchange parameters than untransformed control plants. Here, it is reported for the first time that the overexpression of EaEXPA1 in sugarcane enhances drought tolerance. Thus, EaEXPA1 can be a potential target gene for improving drought tolerance in sugarcane.

甘蔗（Saccharum spp。hybrid）占世界糖产量的80％，是木质纤维素乙醇生产的重要生物量来源，使其成为重要的商业作物。干旱胁迫是降低甘蔗生产力和品质的主要非生物胁迫因素之一。干旱的强度和持续时间的增加，加上对糖的需求的增加，保证了耐旱甘蔗的发展。基因工程为开发优质甘蔗品种提供了潜在的策略，这些品种可以在干旱多发的环境中提高作物的生产力。因此，为了开发耐旱的甘蔗，在本研究中，赋予耐旱性的expansin基因被转化为甘蔗。扩展蛋白基因（EaEXPA1）从斑茅，甘蔗近缘野生，在商业甘蔗品种共86032通过过表达农杆菌介导的转化。与对照植物相比，转基因品系表现出显着更高水平的EaEXPA1表达。V ₁转基因植物在干旱胁迫下的性能评估表明，与未转化的对照植物相比，相对水分含量，细胞膜热稳定性，叶绿素含量，光合效率（Fv / Fm）和气体交换参数明显更高。在此，首次报道甘蔗中EaEXPA1的过表达增强了抗旱性。因此，EaEXPA1 可能是提高甘蔗抗旱性的潜在靶基因。