Characterization of Rhizoctonia solani from potato in Great Britain

Abstract

One hundred and thirty five isolates of Rhizoctonia solani were obtained from British potato crops between 2001 and 2003. Isolates were assigned to anastomosis group (AG) using conventional PCR assays for AG2-1 or AG3 or through the observation of hyphal interactions, where appropriate. A previously published primer set was modified in this study to enhance specificity for AG3PT. Most of the isolates (92·6%) belonged to AG3PT whilst some (6·7%) belonged to AG2-1. Only one isolate recovered (0·7%) belonged to AG5. Isolates of AG2-1 were diverse, with variation in both the length of the rDNA intergenic spacer 1 (IGS1) region and the categories of hyphal interaction observed between pairings of AG2-1 isolates. No variation in the length of the rDNA IGS1 region was observed amongst the AG3 isolates collected. Tests carried out on potato stems with a sub-set of the isolates revealed a wide range of aggressiveness amongst AG2-1 isolates. Sequencing of the rDNA internal transcribed spacer (ITS) region of the AG2-1 isolates and construction of a neighbour joining tree with other AG2-1 sequences available indicated that AG2-1 isolates with the short IGS1 region were closely related. This is the first investigation which provides evidence of the relative AG composition of R. solani populations causing disease in potato crops in Great Britain.

Formation of canker lesions on stems and black scurf on tubers in experimentally inoculated potato plants by isolates of AG2-1, AG3 and AG5 of Rhizoctonia solani: a pilot study and literature review

“…Other studies have indicated that AG2-1 isolates from potato are generally not very virulent on potato plants (Carling andLeiner 1990a, Woodhall et al 2007), which was found also in this study. The black scurf symptoms caused by one Finnish AG2-1 isolate in one experiment were very mild, consistent with previous reports in which AG2-1 has been occasionally recovered from black scurf on tubers grown in the fi eld in Alaska (Carling and), Northern Ireland (Chand and Logan 1983) and the United Kingdom (Woodhall et al 2007).…”

“…In the United Kingdom and France, 93 % and 94 % of the isolates of R. solani characterized from potato belonged to AG3, respectively. The remaining isolates were of AG2-1 or AG5 (Campion et al 2003, Woodhall et al 2007. Similar results indicating predominance of AG3 and occasional occurrence of other AGs have been reported from many other countries including Ireland (Chand and Logan 1983), Alaska ), Canada (Bains and Bisth 1995), USA (Bandy et al 1984(Bandy et al , 1988, Peru (Anquiz and Martin 1989), South Africa (Truter and Wehner 2004), China (Chang and Tu 1980), Japan (Abe and Tsuboki 1978), and Australia (Balali et al 1995).…”

“…Black scurf caused by AG4 has been detected under warm conditions in Peru (Anquiz and Martin 1989). Isolates of AG5 cause black scurf in Australia (Balali et al 1995), South Africa (Truter and Wehner 2004), the United Kingdom (Woodhall et al 2007) and also in Japan where the sclerotia of AG5 form on tubers later than those of AG3 (Abe and Tsuboki 1978). One isolate of AG7 has been found to damage potato sprouts and form black scurf on tubers under cool condition in Mexico (Carling and Brainard 1998).…”

“…However, isolates of other AGs can also form sclerotia on tubers in the field. Black scurf caused by AG2-1 has been detected in Alaska , Northern Ireland (Chand and Logan 1983) and the United Kingdom (Woodhall et al 2007). Black scurf caused by AG4 has been detected under warm conditions in Peru (Anquiz and Martin 1989).…”

A Comprehensive Overview on Black Scurf of Potato

“…Isolates belonging to other AGs (AG-2, AG-4, AG-5, AG-7, AG-8 and AG-9) are associated with potato diseases in different parts of the world, but cause little damage in comparison to AG-3 (Carling et al, 1987(Carling et al, , 1998Bains & Bisht, 1995;Woodhall et al, 2007).…”