Host Specialization in the Charcoal Rot Fungus, Macrophomina phaseolina

Abstract

To investigate host specialization in Macrophomina phaseolina, the fungus was isolated from soybean, corn, sorghum, and cotton root tissue and soil from fields cropped continuously to these species for 15 years in St. Joseph, LA. Chlorate phenotype of each isolate was determined after growing on a minimal medium containing 120 mM potassium chlorate. Consistent differences in chlorate sensitivity were detected among isolates from different hosts and from soil versus root. To further explore genetic differentiation among fungal isolates from each host, these isolates were examined by restriction fragment length polymorphism and random amplified polymorphic DNA (RAPD) analysis. No variations were observed among isolates in restriction patterns of DNA fragments amplified by polymerase chain reaction covering the internal transcribed spacer region, 5.8S rRNA and part of 25S rRNA, suggesting that M. phaseolina constitutes a single species. Ten random primers were used to amplify the total DNA of 45 isolates, and banding patterns resulting from RAPD analysis were compared with the neighbor-joining method. Isolates from a given host were genetically similar to each other but distinctly different from those from other hosts. Chlorate-sensitive isolates were distinct from chlorate-resistant isolates within a given host. In greenhouse tests, soybean, sorghum, corn, and cotton were grown separately in soil infested with individual isolates of M. phaseolina that were chosen based on their host of origin and chlorate phenotype. Root colonization and plant weight were measured after harvesting. More colonization of corn roots occurred when corn was grown in soil containing corn isolates compared with isolates from other hosts. However, there was no host specialization in isolates from soybean, sorghum, or cotton. More root colonization in soybean occurred with chlorate-sensitive than with chlorate-resistant isolates.

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

“…Some workers also related variability to the phenomena of host specialization in M. phaseolina. Su et al, (2001) found host specialization in maize on the basis of pathogenic, genetic, and physiological differences. Similarly, Cloud and Rupe (1988) analyzed host specialization in soybean.…”

Susceptibility of strawberry cultivars to root and crown rot caused by Macrophomina phaseolina

“…The area under the disease progress curve shows that the most Means followed by the same letter in each column are not significantly different, according to Tukey'sHSD test (p ≤ 0.05). 1 Parameters assessed 10 weeks after inoculation. 2 Reduction calculated based on uninoculated control plants.…”

“…is a plant pathogen that attacks a wide range of hosts in more than 500 plant families. It affects crops such as soybean, sorghum, corn, cotton [1], jute [2], sunflower [3], sesame [4], common bean [5], melon [6] and strawberry [7], among others.…”

In vitro mycelial sensitivity of Macrophomina phaseolina to fungicides

“…The fungus showed insensitivity to the active ingredients of fluquinconazole, metalaxyl, thiram and tolyfluanid. sesame, sunflower, bean, cotton, black lentil, chili pepper, maize, tall grass prairie, tomato and watermelon, among others, affecting more than 500 plant species (Machado 1980, Singh et al 1990, Wyllie 1993, Smith & Carvil 1997, Su et al 2001, Saleh et al 2010, Mahdizadeh et al 2011.…”