Anastomosis Groups ofRhizoctonia solaniand BinucleateRhizoctoniaAssociated with Potatoes in Idaho

Abstract

A survey of the relative incidence of anastomosis groups (AG) of Rhizoctonia spp. associated with potato disease was conducted in Idaho, the leading potato producing state in the USA. In total, 169 isolates of Rhizoctonia solani and seven binucleate Rhizoctonia (BNR) isolates were recovered from diseased potato plants. The AG of each isolate was determined through real-time PCR assays for AG 3-PT and phylogenetic analysis of the internal transcribed spacer region of ribosomal DNA. AG 3-PT was the predominant AG accounting for 85% of isolates recovered, followed by AG 2-1 (5.7%) and AG 4 HG-II (4.5%). Two different subsets of AG 2-1 isolates were recovered (subset 2 and 3). Three isolates each of AG A and AG K were recovered, as well as one isolate each of AG 5 and AG W. An experiment carried out under greenhouse conditions with representative isolates of the different AGs recovered from Idaho potatoes showed differences in aggressiveness between AGs to potato stems, with AG 3-PT being the most aggressive followed by an isolate of AG 2-1 (subset 3). The three BNR isolates representative of AG A, AG K and AG W appeared to be less aggressive to potato stems than the R. solani isolates except for the AG 2- 1 (subset 2) isolate. This is the first comprehensive study of the relative incidences of Rhizoctonia species associated with Idaho potatoes and the first study to report the presence of BNR AG W outside of China.

Diversity and Pathogenicity of Anastomosis Groups of Rhizoctonia solani Isolates Associated with Potato Diseases in Northern Sinaloa, Mexico

“…Anastomosis groups (AGs) are an important consideration for diseases caused by Rhizoctonia. Differences exist among AGs in terms of hyphal anastomosis capacity, host range, symptoms and severity of the disease they induce in different hosts, biochemical patterns, fatty acid composition, and DNA sequences, as well as sclerotia production and fungicide sensitivity (Tsror 2010;Ferrucho et al 2012; Woodhall et al 2022). It has been proposed that AGs represent an independent evolutionary unit or phylospecies within the R. solani species complex (González et al 2016).…”

Summer Rice–Winter Potato Rotation Suppresses Various Soil-Borne Plant Fungal Pathogens

“…Potato (Solanum tuberosum L.) and rice (Oryza sativa L.) are the staple food sources for the world population [5], but they could be infected by many soilborne fungal pathogens, such as the most frequently studied pathogenic members from fungal genera of the Colletotrichum [6,7], Fusarium [8], and Rhizoctonia [9][10][11], which could seriously affect crop yield and quality; previous research has estimated that plant soilborne diseases could result in about 10-20% crop yield loss on average [12]. Therefore, healthy cultivated soil is always the option for adopting a potential agricultural system on the existing field [13].…”