Universidade Estadual Paulista "Júlio de Mesquita Filho"/UNESP, CEP 14884-900 Jaboticabal, SP, Brazil.
Universidade Federal de São Carlos/UFSCar, CEP 13600-970 Araras, SP, Brazil.
Int J Food Microbiol. 2018 Jul 2;276:20-27. doi: 10.1016/j.ijfoodmicro.2018.03.019. Epub 2018 Mar 27.
Penicillium italicum (Blue mold) is a major postharvest disease of citrus. An alternative to controlling the disease is through the use of yeasts. The purpose of the present study was to screen effective yeast antagonists against P. italicum, isolated from soil, leaves, flowers, and citrus fruits, to assess the action mechanisms of the yeast isolates that were demonstrated to be effective for biocontrol, and to identify the most effective yeast isolates for the biocontrol of blue mold. The in vitro assays showed that six yeast strains inhibited up to 90% of the pathogen's mycelial growth. In vivo assays, evaluating the incidence of blue mold on sweet oranges, the strains ACBL-04, ACBL-05, ACBL-10 and ACBL-11 were effective, demonstrating the potential for the blue mold control when preventively applied, whereas the ACBL-08 strain showed a high potential to preventive and curative applications. Additional studies on the modes of action of these yeast strains showed that most of the evaluated yeast strains did not produce antifungal substances, in sufficient quantities to inhibit the pathogen growth. Competition for nutrients was not a biocontrol strategy used by the yeast strains. The 'killer' activity might be the main action mechanism involved in P. italicum biocontrol. This study indicated that the multiple modes of action against the pathogen presented by yeasts may explain why these strains provided P. italicum control under in vitro and in vivo conditions. However, further studies in future might be able to elucidate the 'killer' activity and its interaction with pathogen cells and the bioproduct production using Candida stellimalicola strains for control postharvest diseases.
意大利青霉（青霉病）是柑橘类水果的一种主要采后病害。控制这种病害的一种替代方法是使用酵母。本研究的目的是筛选来自土壤、叶片、花朵和柑橘果实的有效拮抗菌酵母，以评估被证明对生物防治有效的酵母分离物的作用机制，并鉴定用于防治青霉病的最有效酵母分离物。体外试验表明，有 6 株酵母菌株可抑制病原菌菌丝生长达 90%。在体内试验中，评估了菌株 ACBL-04、ACBL-05、ACBL-10 和 ACBL-11 对甜橙青霉病的发病率的影响，这些菌株在预防性应用时有效，而菌株 ACBL-08 具有较高的预防和治疗应用潜力。对这些酵母菌株作用模式的进一步研究表明，大多数评估的酵母菌株没有产生足够数量的抗真菌物质来抑制病原菌的生长。酵母菌株没有利用竞争营养物质作为生物防治策略。“杀伤”活性可能是参与意大利青霉生物防治的主要作用机制。本研究表明，酵母对病原菌的多种作用模式可能解释了为什么这些菌株在体外和体内条件下能控制青霉病。然而，未来的进一步研究可能能够阐明利用 Candida stellimalicola 菌株防治采后病害的“杀伤”活性及其与病原菌细胞的相互作用和生物产物的产生。
