Fungal community composition on different potato cultivars during storage
Abstract: The aim of the present study was to investigate the fungal community composition on different cultivars of potato during storage. The study was performed in 2013-2015 by the Latvian Plant Protection Research Centre, evaluating disease presence on seed material of potato tubers after 3 months of storage in storehouses at State Priekuli Plant Breeding Institute and at several farms in different areas in Latvia. At all places conventional potato cultivation was used, with differences concerning previous crop, soil conditions and fungicide application. All isolated fungi were identified based on morphological, cultural, and molecular characteristics using conventional PCR and sequencing a part of the translation elongation factor 1-α-gene for Fusarium species and sequencing a part of the ITS1-5.8S-ITS2 region for other fungi. Analysis of single-conidium isolates of fungi from different cultivars of potato revealed the presence of Fusarium species causing dry rot of tubers during storage period: F. avenaceum (Fries) Saccardo, F. crookwellense (syn. F. cerealis) Burgess, Nelson & Toussoun, F. culmorum (W. G. Smith) Saccardo, F. equiseti (Corda) Saccardo, F. flocciferum Corda, F. oxysporum Schlechtendahl emend. Snyder & Hansen, F. redolens Wollenweber, F. solani (Martius) Appel & Wollenweber emend. Snyder & Hansen, Fusarium torulosum (syn. F. sambucinum, F. sambucinum var. coeruleum, F. venenatum) (Berkeley & Curtis) Nirenberg, F. tricinctum (Corda) Saccardo. Pathogenic fungi Rhizoctonia solani Kühn, Alternaria solani (Ell. & Mart.) L. R. Jones, Alternaria alternata (Fr.) Keissler, A. tenuissima (Kunze) Wiltshire and Phoma exigua var. foveata (Foister) Boerema were found on different potato cultivars. Isolation of Colletotrichum coccodes (Wallr.) S. J. Hughes (syn. C. atramentarium (Brek. & Broome) Taubenhaus), which causes black dot of potato during vegetation period, confirmed a presence of seed-tuber-borne infection in potato seed material. Galactomyces candidum (syn. Geotrichum candidum) de Hoog & M. T. Sm., which causes rubbery rot of potato was isolated from the samples of affected tubers from three cultivars. Appearance of soil saprotrophic fungi Trichocladium asperum Harz., necrotrophic Plectosphaerella cucumerina (L.) Laterr., Humicola fuscoatra Traaen., Torula herbarum (Pers.) Link, Volutella ciliata (Alb. & Schwein) Fr. and Microdochium bolleyi (R. Spraque) de Hoog & Herm.-Nijh. were associated with different growing conditions of potato cultivars.