Identification and pathogenicity of Macrophomina species collected from weeds in melon fields in Northeastern Brazil

Abstract

In this work, a collection of 94 Macrophomina isolates obtained from roots of two weed species, Trianthema portulacastrum and Boerhavia diffusa, collected during surveys conducted during 2015 and 2016 in melon production fields in Northeastern Brazil, were characterized by using molecular techniques. Phylogenetic analysis of the EF1‐α gene allowed the identification of 32 isolates as M. phaseolina and 62 isolates as M. pseudophaseolina. Results of a pathogenicity test performed on melon seedlings of the cv. “Gladial” revealed that all M. phaseolina isolates inoculated were able to cause disease to melon seedlings, but only some M. pseudophaseolina isolates were able to infect them. This study represents the first report of M. pseudophaseolina in both T. portulacastrum and B. diffusa weeds, which are prevalent in the main Brazilian melon producing and exporting regions. Information about the biology and epidemiology of M. pseudophaseolina is scarce because of its recent description; thus, further research is needed for a better understanding of this fungus as a potentially emerging pathogen of melon and other crops.

PATHOGENICITY OF Macrophomina SPECIES COLLECTED FROM WEEDS IN COWPEA

“…(RIOS, 1988) is among the most relevant diseases of cowpea crops in Brazil. Due to the thermotolerant condition of this fungus, this disease becomes even more important in the North-east Brazilian Region, as climatic conditions such as high temperature and low humidity favor its development (ATHAYDE SOBRINHO, 2016;GOMES-SILVA et al, 2017;NEGREIROS et al, 2019b).…”

GENETIC SIMILARITY OF Macrophomina pseudophaseolina ISOLATES ASSOCIATED WITH WEEDS IN THE BRAZILIAN SEMIARID REGION

“…Root rot and vine declining (RRVD), caused by soilborne fungi species, limits melon production in the region (PORTO et al, 2019;SALES JÚNIOR et al, 2012). Species from the genus Macrophomina are commonly reported as the causal agents of RRVD in producing areas in the Northeastern Brazil (NEGREIROS et al, 2019).…”

“…Moreover, species from the genus Macrophomina have been found in association with weed species in off-season cultivation of cucurbits in Northeastern Brazil (SALES JÚNIOR et al, 2012;. Negreiros et al (2019) reported M. pseudophaseolina associated with weed species such as Trianthema portulacastrum and Boerhavia diffusa in melon producing fields in states of CE and RN.…”

“…Studying genetic variability using PCR (Polymerase Chain Reaction)-based molecular markers is an efficient and practical method to assess the genetic diversity among phytopathogenic fungi species (PAPLOMATAS, 2004). Random Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeat (ISSR) are dominant markers that do not require prior knowledge of the genome to detect genetic variability among organisms.…”

Introducing a new Editor‐in‐Chief for Journal of Phytopathology

“…A few papers to highlight from 2018 and 2019 cover biological control with plant growth‐promoting rhizobacteria (Xiang, Lawrence, & Donald, 2018), chemo‐ and thermotherapy with East African cassava mosaic virus (Kidulile, Ateka, Alakonya, & Ndunguru, 2018), pathotypic and molecular evolution of Puccinia striiformis f. sp. tritici (Draz, 2019) and Stagonosporopsis cucurbitacearum pathogenic factors influencing pumpkin seedling survival (Zhao et al, 2019); and in 2019, nematode ascaroside enhanced resistance (Klessig et al, 2019), bioassay development to assess resistance to Fusarium oxysporum in asparagus (Kathe et al, 2019), identification and pathogenicity of Macrophomina species (Negreiros, Sales Júnior, & León, 2019), a rapid detection method for Phytophthora nicotianae (Hieno et al, 2019) and control of rice blast disease caused by Magnaporthe oryzae ( Tamura, Shinzato, Ito, & Ueno, 2019 ).…”