Characterization and pathogenicity of Rhizoctonia isolates associated with cauliflower in Belgium

Abstract

Sixty-two isolates of Rhizoctonia spp. were collected from Belgian cauliflower fields during 2005 and 2006. The majority of the isolates (60 out of 62) had multinucleate cells and were identified as Rhizoctonia solani . Characterization of anastomosis groups (AGs) was performed using pectic zymograms, PCR-RFLP and sequencing of the rDNA-ITS region. The most prevalent AG was AG 2-1 (55% of isolates), followed by AG 2-1 subset Nt (11%), AG 1-1C (8%), AG 5 (8%), AG 4 HGII (6%), AG 3 (5%) and AG 1-1B (3%). Pathogenic potential towards different vegetable crops and towards maize was determined. Damage to cauliflower and endive was caused by different AGs, with the isolates aggressive towards cauliflower belonging to AG 2-1, AG 2-1 subset Nt, AG 4 HGII, AG 1-1C, AG 1-1B and AG 2-2, and those aggressive towards endive belonging to AG 1-1B, AG 1-1C, AG 2-1 subset Nt, AG 2-2, AG 4 HGII and AG 5. The most aggressive isolates towards bean belonged to AG 2-1 subset Nt and AG 2-2, for lettuce to AG 1-1B and AG 2-1, on carrot to AG 4 HGII and towards maize to AG 2-2. Within the isolates of AG 2-1, variability was observed in PCR-RFLP pattern and in aggressiveness towards several crops, indicating this subgroup to be heterogeneous. This is the first study concerning the occurrence of R. solani AGs causing wirestem in Belgian cauliflower fields and the first report of aggressive isolates of AG 1-1C, AG 2-1 subset Nt and AG 4 HGII associated with cauliflower.

Trichoderma atroviride enhances phenolic synthesis and cucumber protection against Rhizoctonia solani

“…The studies were conducted with the Polish isolate of Trichoderma atroviride TRS25 obtained from a growth medium for fungal production and identified using an interactive key for strain identification (http://nt.ars-grin.gov/ taxadescriptions/keys/TrichodermaIndex.cfm), supported by identification keys provided by Gams and Bissett (1998) and Samuels et al (2002) and molecular identification (NCBI GenBank, accession numbers: KJ786731, KJ786812) (Skoneczny et al 2015). R. solani Kühn MUCL 47938 strain used in the experiment is a well characterised, standard phytopathogen of cucumber plants (Pannecoucque et al 2008). Before its application, TRS25 isolate was determined as moderately neutral for R. solani growth without strong antagonistic or mycoparasitic properties (Szczech et al 2014).…”

“…Three weeks after sowing half of the control and TRS25 treated plants were challenged with R. solani (Rs). The soil near their stem base was inoculated with 5 ml of the R. solani mycelial homogenate according to the method of this pathogen application presented by Pannecoucque et al (2008) Biochemical analysis. For HPLC analysis phenolics were extracted according to the modified protocol of Molina et al (2002).…”

Wide Variation in Virulence and Genetic Diversity of Binucleate Rhizoctonia Isolates Associated with Root Rot of Strawberry in Western Australia

“…have been classified into uninucleate, binucleate and multinucleate Rhizoctonia based on the cell nuclear condition [28], [29]. Binucleate Rhizoctonia (BNR) have been divided into 21 anastomosis groups (AG-A to AG-U), and multinucleate Rhizoctonia (MNR) have been divided into 13 anastomosis groups (AG-1 to AG-13) based on hyphal anastomosis reactions [15], [17], [18], [28]–[30]. Both BNR and MNR have been reported as pathogen groups causing root rot on strawberry.…”

Beheersing van bodempathogenen via bodemgezondheidsmaatregelen : Een overzicht van de beschikbare kennis voor een selectie van akkerbouwgewassen met hun bijbehorende bodemziekten

“…Bij bloemkool kan dit pathogeen bij aantasting vroeg in het groeiseizoen leiden tot een aanzienlijke uitval, terwijl een late aantasting voor een verlating van het oogsttijdstip en een slechte koolvorming kan zorgen. Onderzoek heeft uitgewezen dat verschillende Rhizoctonia-isolaten (behorende tot AG 1-1B, AG 1-1C, AG 2-1, AG 2-1 subset Nt, AG 3, AG 4 HGII, AG 5 en AG K) aanwezig zijn in Belgische bloemkoolakkers, maar dat isolaten behorende tot AG 2-1 domineren (Pannecoucque et al, 2008). Anderzijds kunnen isolaten behorende bij AG 2-1 ook bij andere gewassen schade geven, zoals tarwe en koolzaad (Sturrock et al, 2015;Jaaffar et al, 2016), sla (van Beneden et al, 2009b), aardappel (Murdock et al, 2019) of van andere gewassen geïsoleerd worden (bv.…”