Abstract

RODRIGUEZ ALVARADO, Gerardo et al. Vegetative Compatibility Groups Characterization of Fusarium mexicanum Causing Mango Malformation in Jalisco, Mexico. Rev. mex. fitopatol [online]. 2012, vol.30, n.2, pp.128-140. ISSN 2007-8080.

Fusarium mexicanum has been described as the causal agent of mango malformation in several producing areas in Mexico. Isolates of F. mexicanum obtained from mango trees with malformation disease in Jalisco were characterized according to vegetative compatibility groups (VCGs). Isolates were cultured on minimal medium supplemented with potassium chlorate (KClO₃), NO₃^-, and L-asparagine, to generate spontaneous nitrate nonutilizing (nit) mutants. Mutants are detected as mycelia sectors chlorate-resistant, which are not able to utilize nitrate as a nitrogen source due to mutations at loci associated with the nitrate-assimilation pathway. F. mexicanum isolates generated 239 chlorate-resistant sectors of mycelia, out of 62.3 % were nit mutants. Phenotypic characterization detected 36.91 % mutants nit1, 28.18 % mutants nit3, 19.46 % mutants NitM and 14.76 % mutants nnu. Compatibility pairing tests amongst the mutants detected two VCGs in isolates of F. mexicanum from Jalisco. Isolates in one VCG from Jalisco were compatible with isolates of a previously identified VCG of F. mexicanum from Michoacan. A total of three VCGs were detected in the central Pacific region of Mexico.

Keywords : Mutants nit; heterocaryon; anastomosis; VCG; fruit crops; diseases.