Genotypic diversity among brazilian isolates of Macrophomina phaseolina revealed by RAPD

Abstract

Macrophomina phaseolina has been considered one of the most prevalent soybean (Glycine max) pathogens in Brazil. No genetic resistance has been determined in soybean and very little is known about the genetic diversity of this pathogen in tropical and sub-tropical regions. Fifty-five isolates from soybean roots were collected in different regions and analyzed through RAPD for genetic diversity. The UPGMA cluster analysis for 74 loci scored permitted identification of three divergent groups with an average similarity of 99%, 92% and 88%, respectively. The three groups corresponded to 5.45%, 59.95% and 34.6%, respectively of all isolates used. A single plant had three different haplotypes, while 10.9% of the analyzed plants had two different haplotypes. In another study the genetic similarity was evaluated among isolates from different hosts [soybean, sorghum (Sorghum bicolor), sunflower (Helianthus annuus), cowpea (Vigna unguiculata), corn (Zea mays) and wheat (Triticum aestivum)] as well as two soil samples from native areas. Results showed that more divergent isolates originated from areas with a single crop. Isolates from areas with crop rotation were less divergent, showing high similarity values and consequently formed the largest group. Amplification of the ITS region using primers ITS1 and ITS4 produced only one DNA fragment of 620 bp. None of the isolates were differentiated through PCR-RFLP. Our results demonstrated genetic variability among Brazilian isolates of M. phaseolina and showed that one single root can harbor more than one haplotype. Moreover, cultivation with crop rotation tends to induce less specialization of the pathogen isolates. Knowledge of this variation may be useful in screening soybean genotypes for resistance to charcoal rot.

Diversity of Macrophomina phaseolina Based on Morphological and Genotypic Characteristics in Iran

“…The results of the present study clearly demonstrated that M. phaseolina from different parts of the country were highly variable and ISSR markers are suitable to reflect the genetic diversity among the populations. A number of molecular studies elsewhere have shown a high level of polymorphism in this fungus when isolates from different host or geographical origins were compared using different molecular tools (Almeida et al, 2003;Jones et al, 1998;Mayek-Perez et al, 2001;Su et al, 2001;Vandemark et al, 2000). Other recent studies have demonstrated the genetic diversity among M. phaseolina isolates (Aboshosha et al, 2007;Aghakhani and Dubey, 2009;Babu et al, 2010;Baird et al, 2010;Beas-Fernandez et al, 2006;Das et al, 2006;Jana et al, 2005a;Jana et al, 2005b;Omar et al, 2007;Purkayastha et al, 2008;Rajkumar and Kuruvinashetti, 2007;Reyes-Franco et al, 2006;Saleh et al, 2010).…”

“…Different molecular methods have been used for differentiating M. phaseolina populations including Restriction Fragment Length Polymorphism (RFLP) of rDNA-ITS regions (Aghakhani and Dubey, 2009;Almeida et al, 2003;Purkayastha et al, 2006;Su et al, 2001), Random Amplified Polymorphic DNA (RAPD) (Aboshosha et al, 2007;Aghakhani and Dubey, 2009;Almeida et al, 2003;Almeida et al, 2008;Babu et al, 2010;Das et al, 2006;Jana et al, 2003;Omar et al, 2007;Purkayastha et al, Rajkumar and Kuruvinashetti, 2007;Su et al, 2001;Zade et al, 2009), Amplified Fragment Length Polymorphism (AFLP) (Brooker et al, 2008;Mayek-Perez et al, 2001;Reyes-Franco et al, 2006;Saleh et al, 2010;Vandemark et al, 2000), Universal Rice Primer PCR (URP-PCR) (Jana et al, 2005b), Inter simple sequence repeats (ISSR) (Jana et al, 2005a;Purkayastha et al, 2008), Repetitive SequenceBased Polymerase Chain Reaction (Rep-PCR) (Purkayastha et al, 2008) and SSR (Baird et al, 2010). Inter simple sequence repeat (ISSR) markers are powerful tools which can be utilized to access the variation in the flanking regions of microsatellite loci that are dispersed throughout all genomes (Zietkiewicz et al, 1994).…”

Screening a variable germplasm collection of Cucumis melo L. for seedling resistance to Macrophomina phaseolina

“…It has been frequently employed to perform an easy assessment of isolate aggressiveness (Shekhar et al 2006). Phenotypic as well as genetic variation in the pathogen population, even from the same geographical region, has been documented, adding difficulties to the implementation of successful management strategies (Almeida et al 2003;Purkayastha et al 2006;Kaur et al 2012;Mahmoudi and Ghashghaie 2013;Almeida et al 2014). The use of highly aggressive isolates is recommended to optimize the results of screening assays (Mahmoudi and Ghashghaie 2013).…”

Morphological and Pathogenic Variability among Rhizoctonia bataticola Isolates Associated with Soybean (Glycine max L.) from India

“…Isolates having morphological similarity are not necessarily identical genetically, they might have some differences. The variable genetic pattern contributes to variation in morphology and pathogenesis, which has been confirmed by using different molecular tools (Mayek-P´erez et al, 2001;ReyesFranco et al, 2006;Almeida et al, 2003 andJana et al, 2003).As the pathogen has no sexual phase, genetic diversity is produced either by fusion of vegetative cells or by parasexual recombination between nuclear genes (Carlile, 1986). In nature genetic variability improves survival of a fungus (Bashasab, and Kuruvinashetti, 2007).…”