pOsHAK1:OsFLN2提高水稻的糖代谢水平和抗旱性

pOsHAK1:OsFLN2 Expression Enhances the Drought Tolerance by Altering Sugar Metabolism in Rice

糖的合成和转运是植物响应干旱胁迫的关键过程。利用干旱诱导的钾转运蛋白基因OsHAK1的启动子驱动OsFLN2基因的异位表达,可以在干旱胁迫下改善水稻的糖代谢水平,进而促进根系生长。pOsHAK1:OsFLN2转基因植株叶片净光合速率、蔗糖磷酸合成酶活性、韧皮部蔗糖转运速率提高,叶片、根系中的蔗糖含量分别显著减少和增加。pOsHAK1:OsFLN2转基因株系的抗旱性优于野生型(WT)水稻,与WT相比,转基因植株脯氨酸积累量较高,而脂质过氧化水平较低。进一步研究发现,干旱处理的转基因株系中胁迫响应基因显著上调,而衰老相关基因的表达量低于WT。结果表明,通过pOsHAK1:OsFLN2的表达,促进糖分代谢,有利于提高水稻的抗旱性和在干旱胁迫下的生产力。

Sugar synthesis and transport are key processes in plants response to drought stress.Ectopic expression of OsFLN2 gene driven by the promoter of OsHAK1 encoding a drought-enhanced potassium transporter may improve the growth of root system by affecting sugar metabolism in rice under drought stress.The net photosynthetic rate and sucrose phosphate synthase activity in the leaves of the pOsHAK1:OsFLN2 transgenic seedlings increased,but the sucrose contents of the leaves and roots markedly decreased and increased,respectively,resulting from the enhanced sucrose translocation in phloem under drought conditions.pOsHAK1:OsFLN2 transgenic lines demonstrated better tolerance to drought stress than wild-type(WT)ones.In comparison to WT,the transgenic lines had higher accumulations of proline,and lower level of lipid peroxidation.Further investigation revealed that in response to the drought treatment,stress-responsive genes were notably up-regulated in the transgenic plants,however,senescence-associated genes were less abundantly transcribed than in WT.The results suggest that improving sugar metabolism via the expression of pOsHAK1:OsFLN2 may be beneficial to increasing drought tolerance and rice productivity under drought stress.