Testempasis Stefanos, Tanou Georgia, Minas Ioannis, Samiotaki Martina, Molassiotis Athanassios, Karaoglanidis Georgios
Laboratory of Plant Pathology, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University, Thessaloniki, Greece.
Institute of Soil Science and Water Resources, ELGO-Demeter, Thessaloniki, Greece.
Front Plant Sci. 2021 Mar 10;12:644255. doi: 10.3389/fpls.2021.644255. eCollection 2021.
Gray mold caused by the necrotrophic fungus is one of the major postharvest diseases of apple fruit. The exogenous application of 1-methylcyclopropene (1-MCP) and gaseous ozone (O ) is commonly used to ensure postharvest fruit quality. However, the effect of these treatments on the susceptibility of apple fruit to postharvest pathogens remains largely unknown. Herein, the effect of O and 1-MCP treatments on the development of gray mold on apple fruit (cv. "Granny Smith") was investigated. Artificially inoculated apple fruits, treated or not with 1-MCP, were subjected for 2 months to cold storage [0°C, relative humidity (RH) 95%] either in an O-enriched atmosphere or in a conventional cold chamber. Minor differences between 1-MCP-treated and control fruits were found in terms of disease expression; however, exposure to ozone resulted in a decrease of disease severity by more than 50% compared with 1-MCP-treated and untreated fruits. Proteomic analysis was conducted to determine proteome changes in the mesocarp tissue of control and 1-MCP- or O-treated fruits in the absence or in the presence of inoculation with . In the non-inoculated fruits, 26 proteins were affected by 1-MCP, while 51 proteins were altered by ozone. Dynamic changes in fruit proteome were also observed in response to In O-treated fruits, a significant number of disease/defense-related proteins were increased in comparison with control fruit. Among these proteins, higher accumulation levels were observed for allergen, major allergen, ACC oxidase, putative NBS-LRR disease resistance protein, major latex protein (MLP)-like protein, or 2-Cys peroxiredoxin. In contrast, most of these proteins were down-accumulated in 1-MCP-treated fruits that were challenged with . These results suggest that ozone exposure may contribute to the reduction of gray mold in apple fruits, while 1-MCP was not effective in affecting this disease. This is the first study deciphering differential regulations of apple fruit proteome upon infection and postharvest storage treatments, underlying aspects of host response related to the gray mold disease.
由坏死营养型真菌引起的灰霉病是苹果采后主要病害之一。外源施用1-甲基环丙烯（1-MCP）和气态臭氧（O₃）常用于确保采后果实品质。然而，这些处理对苹果果实采后对病原菌易感性的影响仍 largely未知。在此，研究了O₃和1-MCP处理对苹果果实（品种“澳洲青苹”）上灰霉病发展的影响。人工接种的苹果果实，无论是否用1-MCP处理，在富含O₃的气氛中或在传统冷藏库中于0°C、相对湿度（RH）95%的条件下冷藏2个月。在病害表现方面，1-MCP处理的果实与对照果实之间存在微小差异；然而，与1-MCP处理和未处理的果实相比，暴露于臭氧导致病害严重程度降低了50%以上。进行蛋白质组学分析以确定在接种或未接种的情况下对照果实以及1-MCP或O₃处理果实的中果皮组织中的蛋白质组变化。在未接种的果实中，26种蛋白质受1-MCP影响，而51种蛋白质被臭氧改变。响应接种，在果实蛋白质组中也观察到动态变化。在O₃处理的果实中，与对照果实相比，大量与病害/防御相关的蛋白质增加。在这些蛋白质中，变应原、主要变应原、ACC氧化酶、假定的NBS-LRR抗病蛋白、类主要乳胶蛋白（MLP）或2-Cys过氧化物酶还原蛋白积累水平更高。相反，在用接种物挑战的1-MCP处理的果实中，这些蛋白质中的大多数积累减少。这些结果表明，暴露于臭氧可能有助于减少苹果果实中的灰霉病，而1-MCP在影响这种病害方面无效。这是第一项解读苹果果实蛋白质组在感染和采后贮藏处理后的差异调控的研究，揭示了与灰霉病相关的宿主反应的潜在方面。
