大豆PIN-Like(PILS)基因家族的鉴定、表达分析及在根瘤共生固氮过程中的功能

植物激素生长素在植物的生长发育过程中发挥了至关重要的作用,它的稳态和浓度梯度建立控制了几乎所有器官的极性建成。生长素在特定细胞中合成、运输、感知以及代谢降解建立了符合器官发育的生长素浓度梯度。在豆科植物中,根与土壤微生物互作形成了根瘤这一特殊的器官,进行生物固氮。然而,生长素稳态控制生物固氮的功能还未知。拟南芥中的研究表明,PIN-Like (PILS)蛋白协助调节的细胞内生长素稳态,并介导下游细胞核内的生长素信号传递。本研究以大豆作为研究模型,在大豆基因组中鉴定获得19个PILS家族基因(GmPILS),不均匀分布于大豆10条染色体上。GmPILS在大豆9种组织部位中表现出多种表达模式,且具有明显的组织表达特异性。GmPILS1e和GmPILS1f在根瘤菌体区域富集表达,使用人工微RNA沉默(artificialmicro RNA interference,amiRNAi)下调GmPILS1e和GmPILS1f在根瘤的表达,导致根瘤的固氮酶活性上升,而过量表达GmPILS1f导致根瘤的固氮酶活性下降,因此GmPILS1e和GmPILS1f可能参与大豆固氮酶活性的调节。这些结果为进一步解析大豆GmPILS家族基因的功能和作用机制奠定了基础,同时也为结瘤固氮在农业育种中的应用提供了有价值的基因资源。

Identification,expression profile of soybean PIN-Like(PILS) gene family and its function in symbiotic nitrogen fixation in root nodules

Plant hormone auxin plays a vital role in the growth and development of plants.Auxin homeostasis and concentration gradient establishment control the polar formation of almost all organs.The synthesis,transportation,perception,and metabolic degradation of auxin in specific cells establish a concentration gradient of auxin in accordance with organ development.In legumes,roots interact with soil microorganisms to form a special organ called nodules,which is used for biological nitrogen fixation.However,the function of auxin homeostasis control of biological nitrogen fixation is unknown.Studies showed that PIN-Like(PILS) proteins in Arabidopsis helped to regulate intracellular auxin homeostasis and mediate auxin signal transmission in the downstream nucleus.In this study,19 PILS family genes(Gm PILSs) were identified in soybean genome and distributed unevenly on 10 chromosomes of soybean.Gm PILSs exhibited a variety of expression patterns in nine tissue parts of soybean,and had obvious specificity of tissue expression.Gm PILS1 e and Gm PILS1 f were enriched and expressed in the rhizobia region,and the expression of Gm PILS1 e and Gm PILS1 f in nodules was down-regulated by artificial micro RNA interference(ami RNAi),resulting in the increase of nitrogenase activity in the nodules.However,the overexpression of Gm PILS1 f leaded to the decrease nitrogenase activity in root nodules,Gm PILS1 e and Gm PILS1 f might participate in the regulation of soybean nitrogenase activity.These results lay the foundation for further analysis of the function and mechanism of soybean Gm PILS family genes,and also provide valuable genetic resources for the application of nodulation and nitrogen fixation in agricultural breeding.