Classification of Rhizoctonia spp. using rDNA-ITS sequence analysis supports the genetic basis of the classical anastomosis grouping

Abstract

Classifi cation of Rhizoctonia spp. using rDNA-ITS sequence analysis supports the genetic basis of the classical anastomosis grouping Abstract Currently, rDNA-ITS sequence analysis seems to be the most appropriate method for comprehensive classifi cation of Rhizoctonia spp. Our previous review article was concerned with detailed analysis of multinucleate Rhizoctonia (MNR), and the current review complements the previous one with detailed analysis of binucleate Rhizoctonia (BNR) (teleomorphs: Ceratobasidium spp. and Tulasnella spp.) and uninucleate Rhizoctonia (UNR) (teleomorph: C. bicorne). Data of all the appropriate BNR and UNR accumulated in GenBank were analyzed together in neighborjoining (NJ) trees supplemented with percent sequence similarity within and among the anastomosis groups (AGs) and subgroups. Generally, the clusters of the isolate sequences supported the genetic basis for the AG based on hyphal fusion anastomosis. Comprehensive interrelationships among all the currently available MNR, BNR, and UNR groups and subgroups in GenBank were subsequently analyzed in NJ and maximum-parsimony (MP) trees, showing the genetic relatedness among the different groups and indicating possible bridging groups between MNR, BNR, and UNR. The review also indicates serious inaccuracies in designation of sequences of some isolates deposited in GenBank. Several additional teleomorph genera with Rhizoctonia spp. anamorphs have also been reported in the literature. However, as they have not been intensively studied, there were no available data on their rDNA-ITS sequences that could be included in this review.

Virulence and molecular characterization of Costa Rican isolates of Rhizoctonia solani from common bean

“…In this case, the sequences used were 5.8S rDNA with flanking sequences of ITS1 and ITS2. Sharon et al (2008) affirm that there is a difference between ITS 1 and ITS2 in terms of variability. ITS 1 sequences are more variable than ITS2 among fungal isolates, but the combined 3 sequences ITS1 + 5.8S + ITS2 used in this study give more information than either sequence separately.…”

“…Some AG P and AG S, R and Fa clusters have appeared between AG 2-1, AG 2-2 and AG 12. Other AG P isolates cluster together with AGs Fb and E and are between AG 6, AG 1-IC and AG 7 subgroups in some cases (Sharon et al, 2008).…”

“…For some isolates, similarity ranged from 93% to 100%, but for others it was lower, from 90% to 94%. This AG may include several subgroups, but additional work with more isolates is needed to confirm the existence of AG P subgroups (Sharon et al, 2008).…”

The epiphytic orchids Ionopsis utricularioides and Psygmorchis pusilla associate with different Ceratobasidium lineages at Valle del Cauca, Colombia

“…Because these fungi rarely produce sexual spores under culture conditions, this group has always posed a difficulty for taxonomists. The diversity of Rhizoctonia-forming fungi has usually been described with molecular methods, such as sequencing of the internal transcribed spacer (ITS) that is highly variable among groups (Otero et al 2002;2004;Sharon et al 2008). This region is considered the universal barcode for fungal identification (Schochet al 2012) and several oligonucleotides have been developed to address orchid mycorrhizal diversity (Taylor & McCormick 2008).…”

Anastomosis grouping of Rhizoctonia solani and binucleate Rhizoctonia spp. isolated from pepper in Erzincan, Turkey

“…are divided into 14 anastomosis groups: AG-1 to AG-10, AG-BI (Sneh et al 1991), AG-11 (Carling et al 1994), AG-12 (Carling et al 1999), and AG-13 (Carling et al 2002), while binucleate Rhizoctonia spp. (teleomorph: ceratobasidium Rogers) isolates are grouped into AG-A to AG-S (Sneh et al 1991;Sharon et al 2008).…”