Verticillium longisporum

General information about Verticillium longisporum is provided below. Included are a morphological description, comments about morphologically similar species and phylogenetic affiliation. The data is from Inderbitzin et al. (2011) where additional information can be found. Host range data is from Inderbitzin and Subbarao (2014).

Species Description

Verticillium longisporum was described by Stark [42] and in more detail by Karapapa et al. [24]. We documented colony morphology (Figures 9a, 9b), conidia (Figure 9c) and microsclerotia (Figures 9d, 9e, 9f, 9g). We measured microsclerotia and conidia, and assessed the number of phialides per whorl. Microsclerotia were rounded to elongate, 37–240×25–52 µm (Figures 9d, 9e). Conidia were (5.5–) 8.5 µm±2.5 µm (–15.0)×(2.0–) 3.5 µm±1.0 µm (–6.5) (l/w = (1.6–) 2.5±0.7 (–4.5), n = 29). Whorls consisted of (1–) 2–5 (–6) phialides.

Morphologically similar species

Verticillium longisporum resembles V. dahliae but has longer conidia with 8.5×3.5 µm, as compared to V. dahliae with 6.5×3.0 µm.

Figure 9. Select morphological features of Verticillium longisporum.

9a. Colony of strain PD356 after 10 days on PDA, frontal view. 9b. Colony of strain PD356 after 10 days on PDA, frontal view. 9c. Conidia of strain PD348 after 35 days on PDA. 9d. Elongate microsclerotium of strain PD356 after 35 days on PDA. 9e. Rounded microsclerotium of strain PD356 after 35 days on PDA. 9f. Short brown-pigmented hyphae attached to microsclerotium in strain PD348 after 35 days on PDA 9g. Elongate microsclerotium from V. longisporum holotype specimen CBS H-19247. Scale bar: 9a, 9b = 1 cm; 9c–9g = 20 µm; Imaging method: 9a, 9b, = DS; 9c = DIC; 9d–9g = BF.

Evolutionary origin and phylogenetic position

Verticillium longisporum is a diploid hybrid that evolved by at least three separate hybridization events involving three different ancestral species. For a diagram, see Figure 1 in Inderbitzin et al. (2013). Verticillium longisporum belongs to the group of Verticillium that does not produce yellow-pigmented hyphae (group Flavnonexudans). For a phylogenetic tree, see Figure 1 in Inderbitzin et al. (2011).

Host range and geographic distribution

These are inferred from GenBank ITS records, and most likely underestimate the current host range and geographic distribution of V. longisporum. Sugar beet is currently the only known non-Brassicaceae host of V. longisporum confirmed by DNA sequence data.

SubstratesGeographic distribution# plant hosts / # countries
Birdrape (Brassica rapa var. rapa), Broccoli (Brassica oleracea var. botrytis), Cabbage (Brassica oleracea), Cauliflower (Brassica oleracea var. botrytis), Field mustard (Brassica rapa var. rapa), Horseradish (Armoracia rusticana), Oilseed rape (Brassica napus sp. oleifera), Sugar beet (Beta vulgaris), Turnip (Brassica campestris sp. pekinensis), Wild radish (Raphanus raphanistrum) Belgium, France, 10/10 Germany, Italy, Japan,
Netherlands, Russia,
Sweden, UK, USA (CA, IL)10 / 10