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Kiwifruit decay caused by endophytic fungi is affected by exogenous pathogens that trigger changes in fungal community composition and interact with the endophytic fungal community. Four fungal pathogens of kiwifruit were identified. These were Aspergillus japonicus, Aspergillus flavus, Botryosphaeria dothidea, and Penicillium oxalicum. Except for P. oxalicum, the remaining three species represent newly described pathogens of kiwifruit. All four fungal species caused disease and decay in mature kiwifruit. Results of the fungal community analysis indicated that three pathogens that A. japonicus, A. flavus and P. oxalicum were the most dominant, however, other fungal species that did not cause disease symptoms were also present. Positive interactions between fungal species were found in asymptomatic, symptomatic, and infected kiwifruit. The ability of all four pathogens to infect kiwifruit was confirmed in an inoculation experiment. The presence of any one of the four identified pathogens accelerated decay development and limited the postharvest longevity of harvested kiwifruit. Results of the study identified and confirmed the ability of four fungal species to infect and cause decay in harvested kiwifruit. Changes in the structure and composition of the kiwifruit microbiome during the decay process were also characterized. This provides a foundation for the further study of the microbiome of kiwifruit and their involvement in postharvest diseases. [ABSTRACT FROM AUTHOR]

Alternaria alternata is a pathogen in a wide range of agriculture crops and causes significant economic losses. A strain of A. alternata (Y784-BC03) was isolated and identified from "Hongyang" kiwifruit and demonstrated to cause black spot infections on fruits. The genome sequence of Y784-BC03 was obtained using Nanopore MinION technology. The assembled genome is composed of 33,869,130bp (32.30Mb) comprising 10 chromosomes and 11,954 genes. A total of 2,180 virulence factors were predicted to be present in the obtained genome sequence. The virulence factors comprised genes encoding secondary metabolites, including non-host-specific toxins, cell wall-degrading enzymes, and major transcriptional regulators. The predicted gene clusters encoding genes for the biosynthesis and export of secondary metabolites in the genome of Y784-BC03 were associated with non-host-specific toxins, including cercosporin, dothistromin, and versicolorin B. Major transcriptional regulators of different mycotoxin biosynthesis pathways were identified, including the transcriptional regulators, polyketide synthase, P450 monooxygenase, and major facilitator superfamily transporters. [ABSTRACT FROM AUTHOR]