Pathogenic Variation and Molecular Characterization of Macrophomina phaseolina, the Cause of Sesame Charcoal Rot

Abstract

Macrophomina phaseolina (Tassi) Goid is one of the most important soil-borne fungi that affects sesame and causes charcoal rot disease, with a great economic challenge to sesame growers worldwide. Pathogenic and molecular characterizations of eleven M. phaseolina isolates collected from different geographical regions in Egypt were carried out to determine the pathogenicity and genetic diversity. Pathogenicity tests showed a pathogenic variability among the isolates. The identification of M. phaseolina isolates was confirmed by a specific primer and analyzed for genetic diversity using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. The correlation between RAPD analysis of M. phaseolina isolates and their pathogenicity were estimated. Cluster analysis placed the isolates in two distinct clusters and exhibited clear correlation with their pathogenicity. Analysis of ISSR profiles revealed distinct genetic diversity among isolates and showed different clusters according to the geographical regions, in which close geographic origins tend to group nearly. The present study clearly demonstrated that M. phaseolina isolates which were obtained from different geographical regions were highly variable. RAPD and ISSR markers were suitable to reflect the genetic diversity among the studied isolates and could help in DNA finger printing which can be used in future breeding programs of sesame.

Genetic Structure of Macrophomina phaseolina Populations, the Causal Agent of Sesame Charcoal Rot Disease in Iran

“…In the present study, results have shown a high level of polymorphism among M. phaseolina populations of sesame with different geographical origins using neutral ISSR marker in southern Iran. These findings are consistent with previous studies (Aghakhani and Dubey, 2009;Khamari et al, 2023;Khamari et al, 2022;Linhai et al, 2011;Yousef, 2021) that have demonstrated high genetic diversity of M. phaseolina is reflected not only in isolates from different hosts but also within isolates collected from a special host or geographical origin. In general, high genetic diversity levels among a large collection of M. phaseolina populations could be attributed to parasexual recombination between nuclear genes or fusion of vegetative cells favoring heterokaryons, this is corroboration with earlier studies (Carlile, 1986).…”

“…To the best of our knowledge, the present work is a study of population structure of a large collection of M. phaseolina isolates collected from five different climatic regions in Iran; temperate with mild winters (Fars and Kogiluyeh & Boyer-Ahmad provinces), warm and dry winter (Khuzestan province), and warm, dry with cool winter (Bushehr and Hormozgan provinces). ISSR marker has been extensively used for assessing variation within and among M. phaseolina species (Khamari et al, 2023;Khamari et al, 2022;Mahdizadeh et al, 2012;Salahlou et al, 2016;Yousef, 2021). In the present study, results have shown a high level of polymorphism among M. phaseolina populations of sesame with different geographical origins using neutral ISSR marker in southern Iran.…”

“…In the last two decades, the genetic structure of M. phaseolina populations has been investigated with molecular markers e.g., amplified fragment length polymorphic DNA (AFLP) (Linhai et al, 2011;Mayék-Pérez et al, 2001;Saleh et al, 2010), restriction fragment length polymorphisms in the rDNA region (Purkayastha et al, 2006), random amplified polymorphic DNA (RAPD) (Mahdizadeh et al, 2012;Tančić Živanov et al, 2019;Yousef, 2021), and inter simple sequence repeats (ISSR) (Khamari et al, 2023;Khamari et al, 2022;Mahdizadeh et al, 2012;Yousef, 2021). Obtained results were inconsistent in these studies, while some studies disclosed a significant correlation between the geographical locations, genetic diversity and host plants of the isolates (Mahdizadeh et al, 2012;Reznikov et al, 2019); others were not capable to confirm these findings.…”