Characterization of adaptability components of Brazilian isolates of Macrophomina pseudophaseolina

Abstract

Macrophomina pseudophaseolina is a new Macrophomina species reported on different crop and weed species in Brazil, India and Senegal, but to date there are no studies about its adaptability components. In this work a collection of 62 M. pseudophaseolina isolates obtained from roots of the weed species Trianthema portulacastrum and Boerhavia diffusa collected in Northeastern Brazil, was used to: i) study the effect of temperature and salinity on mycelial growth, ii) to determine their sensitivity to the fungicide carbendazim, and iii) to assess their aggressiveness on melon and watermelon seedlings. Results showed variability among M. pseudophaseolina isolates. The optimum temperature for mycelial growth ranged between 26.4 and 38.1ºC.NaCl reduced the in vitro growth of all isolates, which were also highly sensitive to the fungicide carbendazim, exhibiting EC50 values ranging from 0.013 to 0.089 mg L -1 a.i.Disease severity values on melon and watermelon seedlings showed that M. pseudophaseolina isolates were more aggressive in melon than in watermelon.Information about adaptability components of M. pseudophaseolina obtained in this study could be incorporated on breeding programs for melon and watermelon crops.

Inoculation methods and agressiveness of Macrophomina phaseolina isolates in cowpea

“…The most rational strategy for disease control is the use of resistant cultivars. The use of chemical control is limited, as an inhabitant of the soil pathogen, not having much efficiency, in addition to environmental issues (MICHEREFF et al, 2005). However, there are few reports of cultivars with resistance to the disease and the information on inoculation methodologies and reaction evaluation are not consistent in this crop.…”

Characterization of Five New Monosporascus Species: Adaptation to Environmental Factors, Pathogenicity to Cucurbits and Sensitivity to Fungicides

“…and M . pseudophaseolina Crous, Sarr and Ndiaye [ 36 , 42 , 43 ]. The salinity stress is a major environmental constraint in semi-arid cucurbit-growing regions such as northeastern Brazil, where these new Monosporascus species were found.…”

“…Reduction in mycelial growth in vitro by NaCl has also been observed in other cucurbit root fungal pathogens such as Macrophomina phaseolina (Tassi) Goid. And M. pseudophaseolina Crous, Sarr and Ndiaye [36,42,43]. The salinity stress is a major environmental constraint in semi-arid cucurbit-growing regions such as northeastern Brazil, where these new Monosporascus species were found.…”