2024年11月，河南农业大学殷冬梅教授团队在Plant Physiology and Biochemistry上发表了题为“Genome-wide characterization of pyrabactin resistance 1-like (PYL) family genes revealed AhPYL6 confer the resistance to Ralstonia solanacearum in peanut”的研究论文，研究结果发现AhPYL6在花生抗病育种中具备一定的潜力，表明脱落酸受体（PYL）在植物对细菌病原体的防御反应中的潜在作用。研究背景
花生（Arachis hypogaea L.）是全球重要的油料和经济作物，在农业生产中发挥重要作用。然而，花生栽培经常受到各种生物和非生物胁迫的影响。其中，由青枯劳尔氏菌（Ralstonia solanacearum）引起的青枯病是一种主要的细菌性病害。这种病原菌的宿主范围很广，包括花生、西红柿、烟草、马铃薯、辣椒和大豆等作物。青枯病的发生不仅降低了花生产量，而且还会影响花生的品质和栽培效率。因此，全面研究花生对青枯病的抗性机制对于提高花生的抗逆性和促进花生产业的可持续发展至关重要。尽管脱落酸（Abscisic Acid，简称ABA）信号通路已被确认为花生抵抗青枯病的关键因素，但其分子机制仍不明确。我们通过全基因组分析，在花生中鉴定到18个ABA受体（Pyrabactin Resistance 1-Like，简称PYL）家族基因，这些基因在其他植物物种中也具有保守性。研究发现，在花生的这些PYL基因（称为AhPYL）中，AhPYL6和AhPYL16在SA、MeJA、ABA处理以及青枯菌感染下表现出显著的上调。随后，AhPYL6基因全长被克隆并进行功能验证。融合蛋白AhPYL6-YFP主要在烟草叶片的细胞质和细胞核中表达，且AhPYL6的过表达明显增强了植物对青枯菌的抗性。表达分析显示，在烟草叶片中过表达AhPYL6显著上调了包括NbNPR1、NbPR2、NbPR3、NbHRS203、NbEFE26和NbNDR1在内的防御相关基因的表达水平，这表明AhPYL6通过促进防御相关基因的表达来增强植物对青枯菌的抗性。Fig. 1. Genome-wide identification ofAhPYL family genes. (A) Distribution ofAhPYL family genes on the chromosomes ofArachis hypogaea.PYL genes are labeled at the right of the chromosomes, and scale bar on the left indicates the chromosome lengths (Mb). (B) Structure ofAhPYL genes inA. hypogaea. Blue boxes, light green boxes, and blacklines indicate UTRs, exons, and introns, respectively. (C) Motif distribution ofAhPYLs. (D) Conserved protein domain analysis of AhPYLs. (E) Tertiary structure prediction of AhPYL2, AhPYL6, AhPYL8, and AhPYL11 proteins.Fig. 2.Similarity and collinearity analysis ofAhPYL family genes. (A) Similarity analysis of encoding sequence ofAhPYL family genes. (B) Collinearity analysis ofAhPYL family genes inA. hypogaea. (C) Collinearity analysis ofPYL family genes amongA. hypogaea,O. sativa andZ. mays. (D) Collinearity analysis ofPYL family genes amongA. hypogaea,A. thaliana andG. max.Fig. 3.Phylogenetic analysis of thePYL family genes from various plants. The maximum likelihood tree was created using MEGA 7 (bootstrap value = 1000) and the bootstrap value of each branch is displayed (bootstrap value > 70).Fig. 4.Thecis-elements and expression profiling ofAhPYL genes. (A) The promotercis-element analysis ofAhPYL genes. Thecis-acting elements in the promoter regions in the 2000 bp upstream promoter in all selectedAhPYL genes are shown in figure. (B) The expression levels ofAhPYLs in different tissues of peanuts. Expression patterns ofAhPYLs were analyzed based on the available RNA-Seq data in the Peanut Base database. (C) Expression analysis ofAhPYLs in response to SA, MeJA, and ABA. Y-axes indicate relative expression; values are means of three biological replicates, with error bars indicating the SD, and different letters (a–e) among treatments indicate statistically significant differences atp < 0.05 based on the Tukey–Kramer test.
![]()
Fig. 5.Expression analysis ofAhPYL genes in response toR. solanacearum infection. (A) Expression profiles ofAhPYLs underR. solanacearum infection. Fold changes ofAhPYLs were analyzed based on our RNA-Seq data. (B) Expression analysis ofAhPYLs in response toR. solanacearum infection using qRT-PCR. Significant differences were assessed by Mann-WhitneyU test and indicated by asterisks; single asterisk (*) representsp < 0.05, and double asterisk (**) representsp < 0.01. Values are means of three biological replicates, with error bars indicating the SD.
![]()
Fig. 6.Transient overexpression and functional identification ofAhPYL6during resistance toR. solanacearum. (A) Vectors used for transient expression were obtained by cloning full-length CDSs into the vector pCambia1300-YFP. (B) Subcellular localization of AhPYL6-YFP fusion in leaves ofNicotiana benthamiana. (C) Symptoms and mesophyll cell morphology of tobacco leaves transiently overexpressing YFP, AhPYL6-YFP inoculated withR. solanacearum. (D) Trypan blue staining was employed to assess the mesophyll cell death of the lesions caused byR. solanacearum infection; DAB staining was used to measure H2O2 accumulation in tobacco leaves. (E) Trypan blue staining of tobacco leaves as negative control, and leaves overexpressing YFP and AhPYL6-YFP inoculated withR. solanacearum. (F) Lesion area of leaves infected withR. solanacearum.![]()
Fig. 7.AhPYL6 confers the resistance toR. solanacearum through promoting expression of defense -related genes. (A) Expression analysis of defense -related genes in tobacco leaves were investigated by qRT-PCR. (B) The putative AhPYL6-mediated regulatory pathway in peanut resistance toR. solanacearum infection.
研究意义
本研究构建了花生AhPYL6基因对青枯菌胁迫的响应模型图。在花生全基因组中鉴定到18个PYL基因家族成员。基因组学、生物信息学和表达谱联合分析表明，一些AhPYL基因可能受到青枯菌侵染的显著调控，表示AhPYL在花生抗胁迫中发挥重要作用。此外，在烟草叶片中过表达AhPYL6-YFP蛋白增强了对青枯菌的抗性，揭示了ABA受体在植物对细菌病原体防御反应中的潜在作用，为花生ABA信号通路及其与生物胁迫的相互作用提供了更深入的理解。
河南农业大学农学院博士生曹增辉为论文第一作者，河南农业大学殷冬梅教授和任锐副教授为共同通讯作者。该研究得到了国家自然科学基金联合重点项目、河南省重点研发、河南省产业技术体系、河南农业大学高层次人才等项目的资助。殷冬梅教授领衔的河南农业大学花生功能基因组创新团队，依托于河南省花生基因组与分子育种工程技术研究中心，主要从事花生基因组与功能基因挖掘，产量品质性状形成机制与调控等方面的研究。围绕花生种业“卡脖子”等重要科学问题开展工作，已在Advanced Science、Genome Biology、Plant Biotechnology Journal等国际著名期刊上发表了120余篇学术性文章，取得多项原创性研究成果。![]()
