Pathogenic and Genetic Variability within Macrophomina phaseolina from Mexico and Other Countries

Abstract

Pathogenic and genetic characterizations of 96 isolates of Macrophomina phaseolina from Mexico and other countries were carried out in order to define the pathogenic and genetic patterns of diversity and to gain insights into the pathogenic and genetic specialization in this fungus. Isolates were collected from different hosts in Mexico (23 isolates), Italy, Australia, Japan, Argentina, USA, Colombia and Brazil (73 isolates). Pathogenicity was evaluated in seeds of two Phaseolus vulgaris L. cultivars under in vitro conditions, while genotype was determined on the basis of amplified fragment-length polymorphisms (AFLPs). The most frequent pathotypes were 4095 (15 isolates) and 0 (nine isolates), while 59 isolates had a unique pathotype (61%). Cluster analysis showed two contrasting groups of isolates on the basis of pathogenicity, where one group mainly included the most aggressive isolates from Mexico and Colombia. The AFLP analysis produced 418 amplified products and 92.8% were polymorphic. Cluster analysis showed no clear association between AFLP genotype and geographical origin. When subgroups of isolates were re-analysed, we found a clear differentiation between Mexican and non-Mexican isolates. Results confirmed the significant pathogenic and genetic diversity of Macrophomina and showed a clear differentiation between Mexican isolates from all others.

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

“…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). The high genetic diversity of this pleomorphic fungal species is reflected not only in isolates from distinct hosts and geographical origins but also within isolates collected from a single host or geographical origin.…”

“…However, usually isolates from the same host or origin tend to group together. Several studies have found no association between DNA genotype and host origin in populations (Almeida et al, 2003;Reyes-Franco et al, 2006;Vandemark et al, 2000). Recently Saleh et al (2010) used AFLP markers and ITS region sequences to assess the genetic diversity and relationships of M. phaseolina isolates from maize, sorghum, tallgrass prairie and soybean.…”

“…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).…”

Achievements and limitations of contemporary common bean breeding using conventional and molecular approaches

“…This has been observed for many bean pathogens such as rust Sandlin et al (1999); Mmbaga et al 1996a), anthracnose (Ansari et al 2004;Balardin et al 1997), web blight caused by Thanatephorus cucumeris (Godoy-Lutz et al 2003), angular leaf spot caused by Phaeoisariopsis griseola (Mahuku et al 2002;Pastor-Corrales et al 1998) and ashy stem blight caused by Macrophomina phaseolina (Tassi) Goid. (Reyes-Franco et al 2006).…”

First Report of Ashy stem blight caused by Macrophomina phaseolina on Aeonium canariense in Egypt

“…Ashy stem blight exhibits significant morphological, physiological, pathogenic and genetic variability which makes the pathogen more capable of adapting and attacking susceptible hosts in diverse environments. Diversity in M. phaseolina is due to the heterokaryotic condition of mycelium as well as the presence of two asexual sub-phases, one saprophytic (R. bataticola) where microsclerotia and mycelia are mainly produced and another pathogenic [7,8] where microsclerotia, mycelia and pycnidia are produced in host tissues.…”