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ARS Home » Southeast Area » Mayaguez, Puerto Rico » Tropical Crops and Germplasm Research » Research » Publications at this Location » Publication #348305

Title: Characterization of Fusarium spp. isolates recovered from bananas (Musa spp.) affected by Fusarium wilt in Puerto Rico

item GARCIA, RAYMOND - University Of Puerto Rico
item RIVERA-VARGAS, LYDIA - University Of Puerto Rico
item PLOETZ, RANDY - University Of Florida
item CORRELL, JAMES - University Of Arkansas
item Irish, Brian

Submitted to: European Journal of Plant Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2018
Publication Date: 6/7/2018
Citation: Garcia, R.O., Rivera-Vargas, L.I., Ploetz, R., Correll, J.C., Irish, B.M. 2018. Characterization of Fusarium spp. isolates recovered from bananas (Musa spp.) affected by Fusarium wilt in Puerto Rico. European Journal of Plant Pathology.

Interpretive Summary: Bananas are immeasurably important food crops that sustain livelihoods and nutritional needs of many in tropical regions of the world. They are also marketed, accessible and part of daily culture in developed nations. Important plant pathogenic diseases threaten production at all scales. Fusarium wilt, caused by a soilborne, difficult-to-manage fungal plant pathogen continues to evolve and destroy popular banana cultivars. Unfortunately, little to no research exists on fusarium wilt on bananas in Puerto Rico. A detailed characterization of a collection of samples of the fungus collected from affected bananas on the island was conducted. The research identified race 1 and race 2 isolates with narrow genetic diversity among the samples and confirmed the absence of the aggressive Tropical Race 4 (TR4) race. The characterization provides an up-to-date status of the disease on the island and shows that the methods employed can be used to assess possible new incursions of the disease. Keeping out novel fusarium wilt races, including TR4 which affects popular cultivars produced on the island and in the region (Cavendish and Plantains), is critical to Puerto Rican and the regional agricultural economies.

Technical Abstract: Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (FOC), is one of the most destructive diseases of bananas (Musa spp.) worldwide. Although this disease was first reported in Puerto Rico in 1919, current information on the disease is unavailable. We report the first systematic description of FOC on the island. A total of 28 single-spore isolates of Fusarium spp. were recovered from symptomatic bananas from several municipalities. Species identity of the isolates was initially based on morphology and later confirmed with sequences of the translation elongation factor 1a (TEF-1a) gene. Isolates were examined for vegetative compatibility, race identity using PCR primers reported for different races, and virulence on tissue-culture-derived plantlets of differential cultivars for races 1, 2 and 4. Most isolates of F. oxysporum belonged to VCG 0124 of FOC, and amplified with primers designed for race 1. Four race-specific primer sets were evaluated with those developed for race 4 amplifying several isolates. However, no isolate amplified with tropical race 4 (TR4) race-specific primers. Most isolates produced symptoms on race 1 or race 2 differentials. Although some isolates caused minor symptoms on ‘Gran Nain’, disease severities on this race 4 differential were considerably lower than those in susceptible race 1 or race 2 interactions. Based on these results, race 1 and race 2, but not TR4, are present in Puerto Rico. We discuss the disease and FOC’s population structure in Puerto Rico, as well as the reliability of different PCR primers that have been developed to identify races of this pathogen.