草地早熟禾PpSWEET1b基因克隆及功能研究

Cloning of PpSWEET1b Gene from Poa pratensis and Its Functional Verification in Arabidopsis thaliana

SWEETs糖转运蛋白是一类在真核生物和原核生物中均存在的促进糖通过细胞膜流动的转运蛋白之一,参与调控植物的生长发育和胁迫响应过程。以草地早熟禾品种蓝月为材料,以叶片cDNA为模板克隆PpSWEET1b基因,采用花序侵染法转化拟南芥,获得了PpSWEET1b拟南芥过表达株系,并研究干旱和低温胁迫对转基因和野生型拟南芥生长、生理及基因表达的影响。结果表明:干旱和低温胁迫下,PpSWEET1b过表达植株生长状态均优于野生型,叶片MDA含量显著低于野生型,但葡萄糖含量较野生型显著增加,抗旱性和抗寒性明显增强;PpSWEET1b过表达植株可能协同SWEET2和SWEET3共同参与了对低温的响应。此外,以叶片DNA为模板克隆了PpSWEET1b基因的启动子序列,顺式作用元件预测发现,其含有多个与胁迫和激素响应、光响应相关的元件。综合以上结果表明,草地早熟禾PpSWEET1b基因在耐旱和耐寒方面发挥着重要作用,可为草坪草抵抗非生物胁迫生物育种提供新的优异基因资源。

SWEETs sugar transporters are one of the sugar transporters that promoted sugar flow through cell membranes in both eukaryotic and prokaryotic,and are involved in regulating plant growth,development,and stress responses.The PpSWEET1b gene was cloned from the leaf cDNA of Poa praten⁃sis cv.Blue moon as a template,and transformed into Arabidopsis thaliana by inflorescence infection method to obtain overexpressed PpSWEET1b strains.The effects of drought and low temperature stress on the growth,physiology,and gene expression of transgenic and wild-type Arabidopsis thaliana were studied.The results showed that under drought and low temperature stress,the growth phenotype of PpSWEET1b overexpressing plants was better than that of the wild type,and the MDA content in leaves was significantly lower than that of the wild type.However,the glucose content was significantly increased compared to the wild type,and the drought and cold resistance were significantly enhanced;PpSWEET1b overexpressing plants may collaborate with SWEET2 and SWEET3 to participate in the response to low temperature.In addition,the promoter sequence of the PpSWEET1b gene was cloned using leaf DNA as a template,and cis acting elements were predicted to contain multiple elements related to stress,hormone response,and light response.These results indicated that PpSWEET1b gene of Poa pratensis plays an important role in drought and cold tolerance,and can provide new excellent gene resources for biological breeding of turf grass to resist abiotic stress.