Isolation and characterization of bacterial isolates for biological control of clubroot on Chinese cabbage

Abstract

Clubroot caused by Plasmodiophora brassicae is becoming an emerging threat to the production of crucifer vegetable crops in China. The aim of this study was to develop an effective biocontrol strategy against clubroot of Chinese cabbage. Results indicated that six out of fourteen bacterial strains that were isolated from vegetable rhizosphere soil reduced disease severity of Chinese cabbage by more than 50.% under greenhouse conditions.In greenhouse experiments, a soil-drench application of strain YFY 02, 13-1 and HY cell-free culture filtrate reduced the clubroot by 37.7-74.6 % relative to pathogen post-inoculation control on the highly susceptible Chinese cabbage cultivar. Seed treatment of strain YFY 02, 13-1 and HY cell-free culture filtrate reduced clubroot by 23.8-56.0 % in greenhouse experiments. In two field trials conducted at Tonghai and Lufeng sites, cell-free culture filtrates of three isolates reduced clubroot severity on Chinese cabbage by 62.4-76.8 % and 79.4 % -85.1 %, respectively. This efficacy was similar to fungicide Cyazofamid. Based on the sequence analysis of the 16S rDNA gene and identification of biochemical and physiologica criteria l(Biolog carbon source utilization analysis), the strains YFY 02 and HY were identified as Lysobacter antibioticus. To our knowledge, this is the first report of L. antibioticus strains being a promising candidate as a biological control agent against clubroot.

Two New Biocontrol Agents Against Clubroot Caused by Plasmodiophora brassicae

“…Two potential biocontrol strains, F85 and T113 both exhibited good inhibitory effects on germination and viability of resting spores (Supplementary Figure S3), and produced greater than 80% disease suppression in greenhouse experiments. The efficacy of these two strains is better than that of previously reported biocontrol strains (Jäschke et al, 2010;Lahlali et al, 2013;Zhou et al, 2014). In order to improve the efficiency of the biocontrol agents under high disease pressure, it will be necessary to examine the combined effect of F85 and T113 against P. brassicae in the future.…”

The impact of the omics era on the knowledge and use ofLysobacterspecies to control phytopathogenic micro-organisms

“…Moreover, two L. antibioticus strains also controlled the phytopathogenic protist Plasmodiophora brassicae , the causal agent of clubroot of crucifers (Table ; Zhou et al . ).…”

“…The L. antibioticus 13‐6 genome contains a cluster of genes deputed to the production of betalain pigments (Zhou et al . ), whereas the L. capsici AZ78 (Puopolo et al . ) genome encompasses genes involved in the biosynthesis of xanthomonadin‐like pigments sharing homology with genes first identified in L. enzymogenes OH11 (Wang et al .…”

“…The presence of Lysobacter members in suppressive soils has encouraged studies of the characterization of Lysobacter strains as biocontrol agents of phytopathogenic bacteria, fungi, nematodes and oomycetes (Table 1). Moreover, two L. antibioticus strains also controlled the phytopathogenic protist Plasmodiophora brassicae, the causal agent of clubroot of crucifers (Table 1; Zhou et al 2014a).…”

Draft Genome Sequence of Antagonistic Agent Lysobacter antibioticus 13-6

“…The genus Lysobacter represents a source of biocontrol agents, which consisted of 16 species ( 1 , 2 ). Recently, we reported that application of L. antibioticus 13-6 can control brassicae clubroot ( 3 ). Due to its tremendous potential application value, we analyzed the draft genome sequence of L. antibioticus 13-6.…”