激光照射增强小麦抗旱性的分子机制研究

Drought is one of the major factors limiting crop production and quality. Recently it is the hot topic that how to enhance the tolerance of wheat seedlings to drought stress. We found that suitable doses of laser irradiation could enhance tolerance of wheat seedlings to drought stress, which was selected as Research Highlight by Nature China. However, the molecular mechanism of enhanced tolerance of wheat seedlings to drought stress by laser irradiation remains unknown. Our recent work demonstrated that there is significant influence on the transcription level of wheat seedlings under drought stress by laser irradiation. On basis of our previous works, the changes in transcriptome and drought response genes during enhanced tolerance of wheat seedlings to drought stress by laser irradiation will be investigated in wheat seedlings treated Hoagland’s solution, drought stress, laser radiation and laser radiation combined with drought stress, respectively by using molecular biology and bioinformatics methods. Furthermore, construction of the gene expression network of enhanced tolerance of wheat seedlings to drought stress by laser irradiation will be further explored, thus uncovering molecular mechanism of enhanced tolerance of wheat seedlings to drought stress by laser irradiation. The project is the first time to investigate the influence of laser irradiation at the level of transcriptome in wheat seedlings under drought stress, which will help the further studies on the molecular mechanism of enhanced tolerance of wheat seedlings to drought stress by laser irradiation.

干旱是影响小麦品质和产量的重要因素之一，如何提高小麦的抗旱性是当前研究的重点和热点之一。本课题组发现激光照射增强小麦抗旱能力的研究被Nature China作为研究亮点予以报道，但激光照射增强小麦抗旱性的分子生物学机制目前还不清楚。我们近来的研究结果表明，激光照射在转录水平上对干旱胁迫小麦幼苗的基因表达有显著影响。因此，本项目拟在前期研究基础上，以正常生长、干旱胁迫处理、CO2激光处理和CO2激光照射后干旱胁迫小麦幼苗样品为材料，运用分子生物学和生物信息学的手段研究激光照射增强小麦抗旱性过程中转录组及抗旱应答基因发生的变化，进一步构建激光照射增强小麦抗旱性的基因表达网络，进而揭示激光照射增强小麦抗旱性的分子机制。这是首次系统全面的探讨激光辐射技术在转录水平上对干旱胁迫小麦幼苗基因表达的影响，对揭示激光照射增强小麦抗旱性的分子机理研究具有重要的理论意义和潜在的应用价值。

干旱是影响小麦品质和产量的重要因素之一，如何提高小麦的抗旱性是当前研究的重点和热点之一。本课题组发现激光照射增强小麦抗旱能力的研究被Nature China作为研究亮点予以报道，但激光照射增强小麦抗旱性的分子生物学机制目前还不清楚。本项目以正常生长、干旱胁迫处理、激光处理和激光照射后干旱胁迫的小麦幼苗样品为材料，利用高通量Solexa测序技术，分别建立了正常生长、干旱胁迫处理、激光处理和激光照射后干旱胁迫小麦幼苗的数字基因表达谱库（NCBI数据库注册号SRR5119530）。以获得的激光照射干旱胁迫小麦幼苗总的转录组序列为参考数据库，进行基因功能注释，获得了许多编码抗氧化酶（III类过氧化物酶，过氧化氢酶免疫应答结构域，超氧化物歧化酶，谷胱甘肽S-转移酶）、转录因子（WRKY转录因子，蛋白激酶）、光合作用相关蛋白（光系统II PsbR蛋白，叶绿素a / b结合蛋白，ATP合酶），转运相关蛋白（ABC转运蛋白，肽转运蛋白，药物/代谢物转运蛋白，氨基酸转运蛋白，糖/肌醇转运蛋白）等820个激光照射后与抗旱性紧密相关的重要基因，为阐明激光照射增强小麦抗旱性的分子机制储备了大量基因资源。实时荧光定量qRT-PCR结果揭示了部分差异表达基因在激光照射后干旱胁迫小麦幼苗中的特异表达，证实了高通量测序结果的可靠性。进一步利用生物信息学和RLM-RACE 等方法得到5个特异表达基因的全长cDNA序列，构建特异表达基因过表达载体，转化拟南芥得到稳定转化的转基因株系并进行耐旱性表型实验和功能分析。该项目的完成明确了一些关键抗旱应答基因的生物学功能，对揭示激光照射增强小麦抗旱性的分子机理研究具有重要的理论意义和潜在的应用价值。