分根交替灌溉诱导马铃薯抗旱生理机制及关键基因的功能分析

Potato is the world's fourth largest food crop, and water is the key factor that influences potato yield. Scientific water-saving irrigation is very important for improving the drought resistance, reducing waste of resources and increasing crop yields. Partial root-zone drying(PRD) means dry-wet alternately irrigating in different areas of the root system, and local and moderate drought signals applying on roots. Xerophytic signal induces related plant gene activation, and leads to improvement of plant drought-resistance level correspondingly, however, the reaction mechanism is still unclear. This project aims to analyze the effects on the activity of antioxidant enzymes, osmotic regulation and photosynthetic characteristics, so as to determine the mechanisms of PRD improving crop physiological activity in the early potato growth stage. Meanwhile, to obtain the key xeric response genes of PRD by using transcriptome sequencing (RNA-seq) of potato gene expression at the transcriptional level, to screen differentially expressed genes and functional annotation, enrichment analysis and metabolic pathway analysis. Preliminary clarify molecular mechanisms of key xeric genes in potato drought reactions by using RACE device and verify the biological functions of the genes. Therefore, this study has important scientific and practical significance for potato drought-resistant breeding and water-saving irrigation technology application.

马铃薯是世界第四大粮食作物，水分是影响其产量的关键因素。科学的抗旱节水灌溉对于提高植株抗旱性，减少水资源浪费，提高作物产量十分重要。分根交替灌溉（partial root-zone drying PRD）是对不同区域根系干湿交替灌溉，以局部、适度干旱作用于作物根系，由此产生干旱信号诱导植物体相应基因活化，提高植株抗旱性，但其反应机制尚不清楚。本项目拟在马铃薯营养前期进行分根交替灌溉，通过分析对抗氧化酶活性、渗透调节及光合特性的影响，系统阐明PRD提高马铃薯生理活性机制；利用转录组测序（RNA-seq）研究在转录水平上的基因表达，筛选差异表达基因并进行功能注释、富集分析和代谢通路分析，获得与马铃薯PRD抗旱相关的关键基因，利用RACE方法克隆关键基因，进行生物学功能分析，初步阐明这些关键基因在马铃薯PRD诱导抗旱反应中的分子调控机制。本研究为马铃薯分子抗旱育种和实施抗旱节水灌溉提供理论依据。

科学的抗旱节水灌溉对于提高植株抗旱性，减少水资源浪费，提高作物产量十分重要。分根交替灌溉是对不同区域根系干湿交替灌溉，以局部、适度干旱作用于作物根系，由此产生干旱信号诱导植物体相应基因活化，提高植株抗旱性，但其反应机制尚不清楚。本项目拟在马铃薯营养前期进行分根交替灌溉，通过分析对抗氧化酶活性、渗透调节及光合特性的影响，分根交替灌溉提高了应答抗氧化酶过氧化物酶（POD）、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性，而反映胁迫受害程度的丙二醛（MDA）浓度均低于常规灌溉和干旱灌溉处理，分根交替灌溉处理在受到干旱胁迫时马铃薯植株叶片较常规灌溉处理气孔器密度低、闭合程度大，叶绿体和线粒体的受损程度小，叶片细胞保证了细胞器的功能，使马铃薯植株表现较强抗旱性。系统阐明PRD提高马铃薯生理活性机制；在分根交替灌溉条件下，使马铃薯产量比常规灌溉提高4.6％，灌溉水分利用效率比常规灌溉提高25.6％。利用转录组测序（RNA-Seq）研究在转录水平上的基因表达，筛选出5个差异表达基因并进行功能注释、富集分析和代谢通路分析，获得与马铃薯PRD抗旱相关的关键基因，利用RACE方法克隆关键基因，进行生物学功能验证，并初步阐明这些关键基因在马铃薯PRD诱导抗旱反应中的分子调控机制。本研究为马铃薯分子抗旱育种和实施抗旱节水灌溉提供理论依据。