Morphological and Pathological Variability in Rice Isolates of Rhizoctonia solani and Molecular Analysis of their Genetic Variability

Abstract

Nineteen isolates of Rhizoctonia solani collected from different rice varieties grown in various regions of Punjab were studied for their morphological and pathological characterization. Majority of the isolates were fast growing with raised and fluffy colonies and hyphal width of 9.6 lm while four exhibited moderate growth rate. Colony colour in all except two isolates was light yellowish brown. While sclerotial number per 5.0 mm culture disc of the test isolates ranged between 2.1 and 11.2 mm, their size varied between 1.31 and 2.08 mm. Sclerotial colour in all except two isolates was dark brown and most of these were found scattered in the colony. There was no relationship between morphologically similar isolates and their pathogenic behaviour. Majority of the isolates produced lesion length between 45.6 and 58.2 mm on detached rice leaves (cv. PR116). Molecular characterization of genetic diversity in the test isolates was studied by using 10 inter simple sequence repeats (ISSR) and eight random amplified polymorphic DNA (RAPD) markers. The size of amplified DNA bands ranged from 0.25-3.0 to 0.5-4.0 kb with ISSR and RAPD markers, respectively. Combined data set of 155 DNA markers were analysed with UPGMA resulting five clusters with 49-89% genetic similarity. Most of the isolates showed grouping specific to the host variety. Out of these two types of DNA markers, RAPD markers were able to detect more genetic variability when compared to ISSR markers.

Taxonomic Position of Korean Isolates of Rhizoctonia solani Based on RAPD and ITS Sequencing of Ribosomal DNA

“…Recently, molecular biological techniques have been used in combination with morphological and physiological markers for the analysis of R. solani population (Guleria et al, 2007). The restriction fragment length polymorphism (RFLP) studies on ribosomal DNA regions were performed to differentiate AGs and their subgroups (O'Brien, 1994;Vilgalys and Gonzales, 1990).…”

Cultural and Morphological Characterization of Rhizoctonia solani f. sp. sasakii Isolates Collected from Different Districts of Andhra Pradesh

“…Similarly, Guleria et al, (2007), Thind and Aggarwal (2008) and Khodaryari et al, (2009) stated that the R. solani isolates from rice were fast growing with >20 mm mycelia growth rate per day indicating their fast growing nature. Rapid growth rate among R. solani isolates have also been reported by Peltier (1916), Matz (1921), Matsumoto (1934) and Parmeter and Whitney (1970).…”

“…sasakii isolates from maize based on texture and abundance of their mycelia growth and colony appearance. Similarly Guleria et al, (2007) used cultural characters for differentiating the R. solani isolates from rice. Significant variations with respect to colony growth and growth rate were also recorded among the isolates under the study.…”

Screening of Biocontrol Agents Against Rhizoctonia solani Causing Web Blight Disease of Groundnut (Arachis hypogaea L.)

“…Frank) Donk is a widespread and an ecologically diverse soil-borne fungus, causing different types of diseases in many plant species. It causes root rot, stem rot, fruit and seed decay, damping-off, foliar blight, stem canker and crown rot in various crops (Guleria et al, 2007). Understanding the mechanism of action is important because it gives much useful information in determining the maintenance, enhancement and implementation of biological control.…”