Fruit plays an important role in human diet. Whereas, fungal pathogens cause huge losses of fruit during storage and transportation, abuse of chemical fungicides leads to serious environmental pollution and endangers human health. Antagonistic yeasts (also known as biocontrol yeasts) are promising substitutes for chemical fungicides in the control of postharvest decay owing to their widespread distribution, antagonistic ability, environmentally friendly nature, and safety for humans. Over the past few decades, the biocontrol mechanisms of antagonistic yeasts have been extensively studied, such as nutrition and space competition, mycoparasitism, and induction of host resistance. Moreover, combination of antagonistic yeasts with other agents or treatments were developed to improve the biocontrol efficacy. Several antagonistic yeasts are used commercially. In this review, the application of antagonistic yeasts for postharvest decay control is summarized, including the antagonistic yeast species and sources, antagonistic mechanisms, commercial applications, and efficacy improvement. Issues requiring further study are also discussed.

Fruit losses during postharvest storage and handling due to pathogen infections are one of the major problems in the global food chain supply. The application of chemical fungicides to control diseases is currently limited by legislation in some countries and also raises concerns about food and environmental safety. Exploring molecular aspects of pathogen-fruit interactions therefore has biological and economic significance as a means to help develop rational alternatives for disease control. In this review we present the current knowledge of molecular aspects in pathogen-fruit interactions, addressing the following topics: the application of new “omics” technologies for studying these interactions; the molecular mechanisms of fungal pathogen attack; the regulation of virulence by exogenous factors; and, finally, fruit defense mechanisms.Work in Tian’s lab has been funded by the National Natural Science Foundation of China (31530057; 31371863). Work in the LGC lab has been funded by the Spanish Ministry of Economy and Competitiveness (AGL2011-30519-C03-01 and AGL2014-55802-R) and the Generalitat Valenciana (PrometeoII/2014/027). Work in the IRTA lab has been funded by the Spanish Ministry of Economy and Competitiveness by three national projects AGL2008-04828-C01/AGR, AGL2011-30519-C03/AGR and AGL2014-55287-C02.Peer reviewe

Penicillium species are fungal pathogens that infect crop plants worldwide. P. expansum differs from P. italicum and P. digitatum, all major postharvest pathogens of pome and citrus, in that the former is able to produce the mycotoxin patulin and has a broader host range. The molecular basis of host-specificity of fungal pathogens has now become the focus of recent research. The present report provides the whole genome sequence of P. expansum (33.52 Mb) and P. italicum (28.99 Mb) and identifies differences in genome structure, important pathogenic characters, and secondary metabolite (SM) gene clusters in Penicillium species. We identified a total of 55 gene clusters potentially related to secondary metabolism, including a cluster of 15 genes (named PePatA to PePatO), that may be involved in patulin biosynthesis in P. expansum. Functional studies confirmed that PePatL and PePatK play crucial roles in the biosynthesis of patulin and that patulin production is not related to virulence of P. expansum. Collectively, P. expansum contains more pathogenic genes and SM gene clusters, in particular, an intact patulin cluster, than P. italicum or P. digitatum. These findings provide important information relevant to understanding the molecular network of patulin biosynthesis and mechanisms of host-specificity in Penicillium species. Ballester et al. ( MPMI-09-14-0261-FI ) reported similar results and conclusions in MPMI's March 2015 Focus Issue.

Reactive oxygen species (ROS) play a dual role in fruit–pathogen interaction, which largely depends on their different levels in cells. Fruit recognition of a pathogen immediately triggers an oxidative burst that is considered an integral part of the fruit defense response. ROS are also necessary for the virulence of pathogenic fungi. However, the accumulation of ROS in cells causes molecular damage and finally leads to cell death. In this review, on the basis of data regarding ROS production and the scavenging systems determining ROS homeostasis, we focus on the role of ROS in fruit defense reactions against pathogens and in fungi pathogenicity during fruit–pathogen interaction.