AFLP Fingerprinting for Identification of Infra-Species Groups of Rhizoctonia solani and Waitea circinata

Abstract

Patch diseases caused by Thanatephorus cucumeris (Frank) Donk and Waitea circinata Warcup and Talbot varieties (anamorphs: Rhizoctonia species) pose a serious threat to successful maintenance of several important turfgrass species. Reliance on field symptoms to identify Rhizoctonia causal agents can be difficult and misleading. Different Rhizoctonia species and Anastomosis Groups (AGs) vary in sensitivity to commonly applied fungicides and they also have different temperature ranges conducive for causing disease. Thus correct identification of the causal pathogen is important to predict disease progression and make future disease management decisions. Grouping Rhizoctonia species by anastomosis reactions is difficult and time consuming. Identification of Rhizoctonia isolates by sequencing Internal Transcribed Spacer (ITS) region can be cost prohibitive. Some Rhizoctonia isolates are difficult to sequence due to polymorphism of the ITS region. Amplified Fragment Length Polymorphism (AFLP) is a reliable and cost effective fingerprinting method for investigating genetic diversity of many organisms. No detailed analyses have been done to determine the suitability of AFLP for inferring infra-species level of Rhizoctonia isolates. The objective of the present study was to develop AFLP fingerprinting to identify infra-species level of unknown R. solani Kühn and W. circinata isolates. Seventy-nine previously characterized R. solani (n=55) and W. circinata (n=24) isolates were analyzed with AFLP markers generated by four primer pairs. Unweighted Pair Group Method with Arithmetic Mean (UPGMA) correctly grouped R. solani and W.circinata isolates according to their AG, AG subgroup or W.circinata variety. Principle component analysis (PCA) corroborated UPGMA clusters. To our knowledge this is the first time AFLP analysis has been tested as a method to decipher the AG, AG subgroup or W.circinata variety across a wide range of Rhizoctonia isolates.

Divergence of Funneliformis mosseae populations over 20 years of laboratory cultivation, as revealed by vegetative incompatibility and molecular analysis

“…Interestingly, recognition responses previously described in geographically different F. mosseae isolates (Giovannetti et al 2003), represented by the differentiation of lateral tips in the contacted hyphae in correspondence of the approaching ones, were often detected here during contacts between different lineages' hyphae. (Amaradasa et al 2015;Cilliers et al 2000;Okabe and Matsumoto 2000). Accordingly, if we consider the F. mosseae lineages that we analyzed as belonging to a single VCG because all pairings showed hyphal fusions, it is worth comparing their genetic divergence with anastomosis ability.…”

Genetic Diversity and Pathogenicity of Rhizoctonia spp. Isolates Associated with Red Cabbage in Samsun (Turkey)

“…[ 35 , 36 , 37 , 38 , 39 , 40 ]. Genetic differences in hypertension and their subgroups have been phylogenetically assessed using PCR-based DNA fingerprint techniques even in the absence of prior knowledge of the sequences [ 34 , 41 , 42 , 43 , 44 ]. Several studies have reported that Rhizoctonia isolates within many AGs have caused diseases in important crops in Turkey to date [ 11 , 45 , 46 , 47 , 48 , 49 ]; however, there are no detailed reports identifying the AGs and their subgroups of Rhizoctonia isolates causing the root rot and wirestem of red cabbage in Turkey.…”

Detection and Molecular Phylogenetic-Morphometric Characterization of Rhizoctonia tuliparum, Causal Agent of Gray Bulb Rot of Tulips and Bulbous Iris

“…Thus, although the ITS (ITS-5.8S-ITS2) primary sequences of all the three isolates of Rtul formed a well-supported clade in the phylogenetic tree (Figure 6), molecular morphometric analyses clearly differentiated them as three potentially distinct sexual species within R. tuliparum, sensu lato, per Müller et al [45] and Wolf et al [31] (Figure 8; Table S4), and call for further investigation. Moreover, from disease epidemiology and management viewpoints, our findings call for accurate identification of pathogen genotypes as well as determination of sensitivities of genetically diverse isolates of Rhizoctonia pathogens to commonly used fungicides [13,43,[47][48][49][50].…”