Identification and Characterization of a Novel Etiological Agent of Mango Malformation Disease in Mexico, Fusarium mexicanum sp. nov.

Abstract

The primary objective of this study was to characterize Fusarium spp. associated with the economically devastating mango malformation disease (MMD) in Mexico. In all, 142 Fusarium strains were isolated from symptomatic mango inflorescences and vegetative tissues in eight geographically diverse Mexican states from 2002 through 2007. Initially, all the Mexican isolates were screened for genetic diversity using appolymerase chain reaction and random amplified polymorphic DNA markers and were grouped into seven distinct genotypes. Based on results of these analyses, evolutionary relationships and species limits of the genetically diverse MMD-associated Fusarium spp. were investigated using multilocus DNA sequence data and phylogenetic species recognition. Maximum parsimony analyses of a five-locus data set comprising 5.8 kb of aligned DNA sequence data indicated that at least nine phylogenetically distinct Fusarium spp. within the Gibberella fujikuroi species complex are associated with MMD, including one species within the African clade (Fusarium pseudocircinatum), two species within the Asian clade (F. mangiferae and F. proliferatum), and at least six species within the American clade (F. sterilihyphosum and five undescribed Fusarium spp.). Molecular phylogenetic analyses indicate that a novel genealogically exclusive lineage within the American clade was the predominant MMD associate in Mexico. This new Fusarium sp. caused MMD and could be distinguished from all other known species morphologically by the production of mostly sterile, coiled hyphae which are typically associated with sporodochial conidiophores together with unbranched or sparsely branched aerial conidiophores. Koch's postulates were completed for isolates of the new species on nucellar seedlings of mango cv. Ataulfo. This pathogen is formally described herein as F. mexicanum.

Fusarium species associated with plants in Australia

“…Fusarium mexicanum T. Aoki et al This species was described by Otero-Colina et al (2010) from isolates causing mango malformation disease in Mexico. As it has been shown to cause mango malformation disease it is of quarantine importance for Australia.…”

New Insights into Mango Malformation Disease Epidemiology Lead to a New Integrated Management Strategy for Subtropical Environments

“…Another MMD causal agent, F. mexicanum sp. nov., was described from Mexico (55). With multilocus sequenc ing, F. mexicanum was shown to differ significantly from other MMD taxa in the G. fujikuroi species complex (55,65) (Fig.…”

“…How ever, descriptions of the MMD agents in the Western Hemisphere have only been made in Florida, Brazil (36), and Mexico (55,65). Additional work is needed to determine whether F. mangiferae occurs elsewhere in the West.…”

“…MMD was first reported in India in 1891 (29), and has subse quently been observed in Australia, Brazil, China, Egypt, El Salva dor, India, Israel, Malaysia, Mexico, Myanmar, Nicaragua, Oman, Pakistan, Senegal, South Africa, Spain, Sri Lanka, Sudan, Swazi land, Uganda, and the United States (2,3,8,9,15,24,29,31,34,37,42,51,55,64,67,70,77). Since the pathogen is easily disseminated in infected germplasm and there are conspicuous gaps in its geo graphic distribution, malformation may be even more widely spread (58).…”

First evidence of ethylene production byFusarium mangiferaeassociated with mango malformation

“…Ethylene might be produced through 2-oxoglutarate-dependent oxygenase-type ethylene-forming-enzyme (EFE) pathway in Fusarium sp, which needs to be investigated. 11 Present scenarios of mango malformation rely on the fact that Fusarium sp is having a wide acceptability in the scientific community as a causal agent of this disease. Recently, it has been reported that F. mangiferae is associated with mango malformation in Spain and Europe.…”