Impacts of abiotic factors on the fungal communities of ‘Honeycrisp’ apples in Canada

Authors: MCLAUGHLIN, M - Dalhousie University; Yurgel, Svetlana; ABBASI, PERVAIZ - Agriculture And Agri-Food Canada; PRITHIVIRAJ, BALAKRISHNAN - Dalhousie University; ALI, SHAWKAT - Agriculture And Agri-Food Canada

Submitted to: Microbial Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2022
Publication Date: 12/21/2022
Citation: McLaughlin, M.S., Yurgel, S., Abbasi, P.A., Prithiviraj, B., Ali, S. 2022. Impacts of abiotic factors on the fungal communities of ‘Honeycrisp’ apples in Canada. Microbial Biotechnology. 16(8):1639–1656. https://doi.org/10.1111/1751-7915.14207.
DOI: https://doi.org/10.1111/1751-7915.14207

Interpretive Summary: Apple fruit is vulnerable to spoilage by many diseases caused by fungi. However, not all fungi cause disease, and many fungi are beneficial. Like other plants parts, apple fruit has its own community of fungi that can influence fruit quality, as well as susceptibility to disease. Understanding how these communities change in different conditions will contribute to reducing fruit loss and improving fruit quality. Because the fungal communities can vary based on factors including location, weather, and even cultivar, it is not always beneficial to apply results obtained by analysis of plants from one growing region to another. Rather, studies need to be conducted in each growing region with the most economically important cultivars to establish accurate data. This study was the first to investigate fungal communities of Honeycrisp apples in Maritime Canada. We evaluated the dynamics of fungal communities of apple fruit across factors such as tissue-type, management practice, province of origin and weather conditions across 2019-2020 seasons. We found that weather conditions had the greatest impact on fungal communities, and that these factors influenced populations of both beneficial and pathogenic fungi. In the future, understanding the influence of these factors on the fungal community of this cultivar will help to improve disease management strategies.

Technical Abstract: The maintenance of healthy plant microbiome is an emerging concept of disease management, and necessitates a clear understanding of plant-microbiomes and the various factors that affect this microbiome. While a number of studies have investigated the microbiome of apple fruit, variations in the microbiome of apple fruit have been observed based on management strategies, tissue type, growing season, geographical location and plant genotype. Therefore, studies investigating the microbiome of economically significant cultivars within each growing region are necessary for the development of adequate disease control strategies. In the Maritimes, ‘Honeycrisp’ is the most economically significant cultivar. This is the first study to investigate the fungal microbiome of ‘Honeycrisp’ apple fruit in this growing region, and compares the effect of management practices, province of origin (geographical location) and weather conditions on the fungal microbial communities on and in apple fruit tissues at harvest. Variation in fungal composition between different fruit tissues was also observed in the study. Though apple fruit tissue was dominated by relatively few fungal genera, significant changes in their fungal communities were observed as a result of all four variables, including shifts in genera with plant-associated lifestyles (symbionts and pathogens) such as Aureobasidium, Alternaria, Penicillium, Diplodia and Mycosphoaerella. We demonstrate that weather conditions are the most significant factor affecting fungal communities structure and diversity of apple, suggesting that future microbiome studies should take place over multiple growing seasons to better represent the host-microbiome of perennial crops under different environmental conditions.