Soybean - Macrophomina phaseolina specific interactions and identification of a novel source of resistance

REZNIKOV, S; CHIESA, MA; PARDO, EM; DE LISI, V; BOGADO, N; GONZALES, V; LEDESMA, F; MORANDI, E; PLOPER, DL; CASTAGNARO, AP

PHYTOPATHOLOGY

AMER PHYTOPATHOLOGICAL SOC

Año: 2018 vol. 109 p. 63 - 73

0031-949X

Charcoal rot, caused by the fungus Macrophomina phaseolina, 1 is an economically2 important disease of soybean (Glycine max) worldwide. Objectives of the present research3 were to (i) study the genetic and pathogenic diversity in a collection of M. phaseolina4 isolates from Argentina and Paraguay and (ii) develop an improved in vitro phenotyping5 method to evaluate disease response of soybean genotypes to M. phaseolina isolates.6 Cluster analysis showed no clear association among simple sequence repeats (SSR)7 profiles, year of collection, pathogenicity and geographical origin of the isolates from8 Argentina and Paraguay. Subsequently, the response of four soybean genotypes against9 seven M. phaseolina isolates was evaluated in the field and the results were confirmed10 using the in vitro assay developed. This assay, which is based on root disease development11 on soybean seedlings, allowed the detection of a differential level of aggressiveness among12 the isolates on four soybean genotypes. The results suggest the existence of specific13 interactions among soybean genotypes and M. phaseolina isolates. In addition, cultivar14 Munasqa RR showed a superior response against M. phaseolina compared with DT 97-15 4290 (moderately resistant), thus becoming a novel source of resistance to charcoal rot.