Functional genomics of the biocontrol agent-plant pathogen interaction pseudozyma flucculosa-powdery mildews

无论是通过使用天敌还是通过诱导植物的自然防御机制，对植物病原体进行生物控制的实际应用，都需要对这些现象背后的遗传、分子和生态事件有透彻的了解。这一挑战一直是过去20年来申请人实验室开展的研究活动的焦点。在上一期中，我们在阐明控制白粉病真菌天然拮抗剂假酶（Pseudozyma cullosa）生物防治特性的复杂因素方面取得了一些重大进展。特别有意义的是，我们报道了以下几点：1)开发了gfp -转化体来研究絮凝假单胞菌-植物-白粉病的营养相互作用；2) BCA分泌的重要次级代谢物絮凝素对医用重要病原菌的抑菌活性；3)拟酵素转化新技术的发展；4)发现并描述了BCA对絮凝素的分解代谢活性；5)通过蛋白质组学和基因组学分析，确定了与絮凝素特异性生物防治活性相关的营养和生态因子；6)发现了参与絮凝素生物合成的基因和基因簇，并与系统发育相关的植物病原体模式真菌黑木耳建立了意想不到的密切联系。后一项成果被认为是一项重大突破，因为它为以下方面开辟了道路：1)基于真菌基因组测序对絮状假单胞菌基因组的特权观察；2)比较功能基因组分析，将定义使真菌成为有益的BCA或植物病原体的微妙遗传和进化事件。在此应用背景下，根据我们的最新进展，目标是：1)完成絮状假酶的基因组组装；2)对絮凝菌进行基因组注释，重点研究调控絮凝素合成的基因簇和调控絮凝素合成的类似基因簇；3)进行功能基因组比较分析，以确定赋予絮状假单胞菌和麦氏假单胞菌不同生活方式的特定成分。这些目标的实现将在以下方面产生新的和独特的信息：调节P.絮凝菌对白粉病真菌生物防治活性的遗传决定因素；这些决定因素的表达（或抑制）如何影响真菌的生态。这些结果将对植物病理学领域产生深远的影响，因为我们的模型将为分离和调节两种系统发育相关的真菌作为生物防治剂或植物病原体的内在遗传因素提供独特的数据。

Practical application of biological control of plant pathogens, either through the use of natural enemies or through the induction of the plant's natural defense mechanisms, presupposes a thorough understanding of the genetic, molecular and ecological events underlying such phenomena. This challenge has been the focal point of the research activities carried out in the applicant's laboratory over the last 20 years. In the previous installment, we have made some major strides toward elucidating the complex factors governing the biocontrol properties of Pseudozyma flocculosa, a natural antagonist of powdery mildew fungi. Of particular significance, we reported the following: 1) the development of GFP-transformants to study the tritrophic interaction P. flocculosa-plant-powdery mildew ; 2) the antifungal and antibacterial activity of flocculosin, an important secondary metabolite secreted by the BCA, against pathogen strains of medical importance; 3) the development of a novel technique to transform Pseudozyma spp.; 4) the discovery and description of catabolitic activities by the BCA against flocculosin and 5) identification of nutritional and ecological factors linked with the specific biocontrol activity of P. flocculosa through proteomic and genomic analyses; and 6) discovery of genes and a gene cluster involved in flocculosin biosynthesis and establishment of an unsuspected close link with the phylogenetically related plant pathogen model fungus Ustilago maydis. This latter achievement is perceived as a major breakthrough since it opens the way to 1) a privileged look into the genome of P. flocculosa based on the sequenced genome of U. maydis and 2) to comparative functional genomic analyses that will define the subtle genetic and evolutive events that make a fungus a beneficial BCA or a plant pathogen. In the context of this application and on the basis of our recent progress, the objectives are: 1) to complete the genome assembly of Pseudozyma flocculosa; 2) to carry out genomic annotation of P. flocculosa with particular emphasis on the gene cluster regulating flocculosin synthesis and the similar cluster regulating ustilagic synthesis in U. maydis; and 3) to conduct comparative functional genomic analyses with the aim to identify the specific components that confer different lifestyles to P. flocculosa and U. maydis. Fulfillment of these objectives will generate novel and distinctive information with regards to: the genetic determinants that regulate the biocontrol activity of P. flocculosa against powdery mildew fungi; how expression (or repression) of these determinants influence the ecology of fungi. These results will have far reaching impact into the field of plant pathology as our model will provide unique data into the intrinsic genetic factors that separate and modulate two phylogenetically related fungi to behave as biocontrol agent or plant pathogen.