Tropical Race 4 and Race 1 strains causing Fusarium wilt of banana infect and survive inHeliconiaspecies and ornamental bananas

Abstract

ABSTRACTFusarium wilt of banana (FWB), caused by soilborneFusariumspp., is a major global threat to the cultivation of bananas. In addition to persistent chlamydospores, weeds are a reservoir of the causal agents. However, it remains unclear whether other Zingiberales species, which are grown in the same geographic regions, also can serve as hosts forFusariumspp. that cause FWB. Greenhouse assays were conducted to investigate whetherFusarium phialophorum(Race 1; pathogenic to Gros Michel banana) andFusarium odoratissimum(TR4; pathogenic to Cavendish banana) can infect threeHeliconiaspecies, two ornamental banana species orMusa textilis(abacá).Heliconia latispatha, Musa balbisiana, andMusa coccineadisplayed external symptoms after inoculation with TR4, while inoculation with Race 1 caused symptoms inH. latispatha, H. psittacorum, M. coccinea, andM. velutina. Isolates recovered from distinct organs of all studied plant species were characterized and re-isolated strains caused FWB symptoms in Gros Michel and Cavendish banana plants, and their rhizome discolored area scores were similar to the reference strains. The susceptibility of some ornamental species and the presence ofFusariumstrains as asymptomatic endophytes in others, with remaining pathogenicity, call for a revision of the race nomenclature and the current containment protocols for FWB.