An Analysis of Postharvest Fungal Pathogens Reveals Temporal-Spatial and Host-Pathogen Associations with Fungicide Resistance-Related Mutations

Fungicides are the primary tools to control a wide range of postharvest fungal pathogens. Fungicide resistance is a widespread problem that has reduced the efficacy of fungicides. Resistance to FRAC-1 (Fungicide Resistance Action Committee-1) chemistries is associated with mutations in amino acid position 198 in the β-tubulin gene. In our study, we conducted a meta-analysis of β-tubulin sequences to infer temporal, spatial, plant host, and pathogen genus patterns of fungicide resistance in postharvest fungal pathogens. In total, data were acquired from 2,647 specimens from 12 genera of fungal phytopathogens residing in 53 countries on >200 hosts collected between 1926 and 2020. The specimens containing a position 198 mutation were globally distributed in a variety of pathosystems. Analyses showed that there are associations among the mutation and the year an isolate was collected, the pathogen genus, the pathogen host, and the collection region. Interestingly, fungicide-resistant β-tubulin genotypes have been in a decline since their peak between 2005 and 2009. FRAC-1 fungicide usage data followed a similar pattern in that applications have been in a decline since their peak between 1997 and 2003. The data show that, with the reduction of selection pressure, FRAC-1 fungicide resistance in fungal populations will decline within 5 to 10 years. Based on this line of evidence, we contend that a β-tubulin position 198 mutation has uncharacterized fitness cost(s) on fungi in nature. The compiled dataset can inform end users on the regions and hosts that are most prone to contain resistant pathogens and assist decisions concerning fungicide resistance management strategies.

Assessment of banana fruit handling practices and associated fungal pathogens in Jimma town market, southwest Ethiopia

Banana fruits are highly perishable and affected by different microbial contaminates because ripe bananas are very perishable. One of the most important factors causing great economical loss of banana fruits is postharvest fungal diseases caused by lack of proper handling along postharvest chains. In line with this, the study was carried out to assess banana fruits handling practices and identify the major causal agents of postharvest fungal disease of banana fruits in Jimma town of bishishe market. Assessment was carried out using purposive sampling to select the study area, followed by simple random sampling to collect information on handling practices through observation and interview using pretested questioners. The survey result revealed that losses of banana fruits due to spoilage and physical injury were common problems for all fruit vendors. Practices such as lack of sanitation, temperature management, and improper packaging and transportation problems were identified among the common causes for observed losses. A total of 48 fruits were purposively selected from open market, wholesales and retailers and fruit damage, disease incidence, disease severity and identification of diseases causing fungal pathogen were conducted under laboratory. The highest fruit damage (56.2%) was recorded in sample taken from retailers' shop, and the associated disease incidence and severity were 54.2% and 34%, respectively. Morphological identification of pure culture revealed that anthracnose caused by Colletotrichum musae and crown rot caused by fusarium spp. are the most important disease causing agents and result in large percentage of fruit loss in Jimma town of bishishe market.