Characterization of Two Fungal Isolates from Cotton and Evaluation of their Potential for Biocontrol of Verticillium Wilt of Cotton

Abstract

Two isolates (CVd‐WHw and CVn‐WHg) recovered from Verticillium‐wilt‐symptomatic cotton grown in Hubei Province of China were identified based on their morphology, growth characteristics in culture, specific amplification and identification of internal transcribed spacer (ITS) rDNA sequence. According to the morphological characteristics, specific PCR amplification and ITS sequences, CVd‐WHw was identified as V. dahliae and CVn‐WHg as Gibellulopsis nigrescens. In bioassays, the two isolates had significantly lower pathogenicity to cotton plant than V. dahliae isolate CVd‐AYb. Cotton pre‐inoculated with isolate CVn‐WHg or CVd‐WHw exhibited reduced disease indices of Verticillium wilt compared with those inoculated with CVd‐AYb alone. Cotton co‐inoculated with CVn‐WHg or CVd‐WHw and CVd‐AYb provided increased protection from subsequent CVd‐AYb inoculation. These results suggest that the two isolates have the potential to be developed as biocontrol agents for the control of Verticillium wilt in cotton. To our knowledge, this is the first report of a cross‐protection phenomenon using Gibellulopsis nigrescens against Verticillium wilt caused by V. dahliae on cotton.

Soil Microbial Community Development in a Cherry Replant Site

“…Gibellulopsis nigrescens (Synonymy: Verticillium nigrescens) as a highly controversial Verticillium spp., is pathogenic on many crops (such like potato, tomato, antirrhinum, eggplant, soybeans and M. sativa [34][35][36][37][38]. However, the recent report revealed that G. nigrescens was a promising biocontrol agent for Verticillium wilt of cotton [39].…”

Functional Analysis of the Pathogenicity-Related Gene VdPR1 in the Vascular Wilt Fungus Verticillium dahliae

“…Each strain was inoculated onto 8–10 cotton seedlings at the first euphylla stage by immersing the seedling roots in the conidial suspension. This experiment was replicated three times [38]. The inoculated cotton seedlings were cultivated in a standard greenhouse at 25–30°C under a 16-h/8-h light–dark photoperiod.…”

“…Disease progress was recorded from 7 to 24 dpi. The disease index (DI) was calculated based on a five-scale categorization of Verticillium wilt disease on cotton seedlings [38]. …”

Isolation and functional analysis of the pathogenicity-related gene VdPR3 from Verticillium dahliae on cotton

“…Symptom development was observed from 7 to 26 days after inoculation. Disease severity was rated according to a disease index (DI) based on five-scale categorization of Verticillium wilt disease on cotton seedlings (Zhu et al 2013). The infection assay was repeated three times for each mutant.…”

“…The inoculation concentration was uniformly adjusted to 1 × 10 7 CFU/mL. The infection assay procedure is detailed in our previous report (Zhu et al 2013). Symptom development was observed from 7 to 26 days after inoculation.…”