Baccelli Ivan, Luti Simone, Bernardi Rodolfo, Favaron Francesco, De Zotti Marta, Sella Luca
Institute for Sustainable Plant Protection, National Research Council of Italy, Sesto Fiorentino, Italy.
Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy.
Front Plant Sci. 2022 May 19;13:881961. doi: 10.3389/fpls.2022.881961. eCollection 2022.
Peptaibols are non-ribosomal linear peptides naturally produced by a wide variety of fungi and represent the largest group of peptaibiotic molecules produced by species. Trichogin GA IV is an 11-residue peptaibol naturally produced by . Peptaibols possess the ability to form pores in lipid membranes or perturb their surface, and have been studied as antibiotics or anticancer drugs in human medicine, or as antimicrobial molecules against plant pathogens. When applied to plants, peptaibols may also elicit defense responses. A major drawback to the exploitation and application of peptaibols in agriculture is their poor water solubility. In a previous study, we designed water-soluble Lys-containing Trichogin GA IV analogs, which were able to inhibit the growth of several fungal plant pathogens . In the present study, we shed light on the mechanism underpinning their efficacy on plants, focusing on six Trichogin GA IV analogs. Our results highlighted peptide hydrophilicity, rather than helix stability, as the major determinant of their activity against infection in tomato leaves. The peptides showed preventive but not curative efficacy against infection, and lack of translaminar activity, with results reproducible on two tomato cultivars, Marmande and Micro-Tom. Reactive oxygen species (ROS) detection analysis in tomato and , and expression of defense genes in tomato, highlighted a transient and limited impact of the peptides on the plant defense system. The treatment did not result in significant modulation of defense genes or defense priming. The antimicrobial effect thus emerges as the only mechanism behind the plant protection ability exerted by water-soluble Trichogin GA IV analogs, and limited effects on the plant metabolism are expected to occur.
短杆菌肽是由多种真菌天然产生的非核糖体线性肽，是该物种产生的最大一类抗微生物肽分子。Trichogin GA IV是一种由……天然产生的11个残基的短杆菌肽。短杆菌肽具有在脂质膜中形成孔或扰乱其表面的能力，并且已作为人类医学中的抗生素或抗癌药物，或作为针对植物病原体的抗菌分子进行研究。当应用于植物时，短杆菌肽也可能引发防御反应。短杆菌肽在农业中的开发和应用的一个主要缺点是它们的水溶性差。在先前的一项研究中，我们设计了含赖氨酸的水溶性Trichogin GA IV类似物，其能够抑制几种真菌植物病原体的生长。在本研究中，我们揭示了它们对植物有效性的潜在机制，重点研究了六种Trichogin GA IV类似物。我们的结果强调了肽的亲水性，而不是螺旋稳定性，是它们对番茄叶片感染活性的主要决定因素。这些肽对感染表现出预防作用而非治愈作用，并且缺乏跨层活性，结果在两个番茄品种Marmande和Micro-Tom上具有可重复性。番茄和……中的活性氧（ROS）检测分析以及番茄中防御基因的表达，突出了这些肽对植物防御系统的短暂和有限影响。该处理并未导致防御基因的显著调节或防御引发。因此，抗菌作用是水溶性Trichogin GA IV类似物发挥植物保护能力背后的唯一机制，并且预计对植物代谢的影响有限。
