Microbial Consortia: an Engineering Tool to Mitigate the Clubroot Incidence on Chinese Cabbage by Reshaping the Rhizosphere Microbiome

Abstract

Clubroot disease caused by Plasmodiophora brassicae is a serious threat to Chinese cabbage (Brassica rapa L. ssp. pekinensis) production, which results in extensive yield losses. At present, clubroot control mainly depends on pesticides that have food safety concerns, and the application of sole biocontrol agents cannot successfully control the disease. In this study, we investigated the biocontrol effect of Bacillus cereus BT-23, Lysobacter antibioticus 13-6, and Lysobacter capsici ZST1-2 as sole strains, intra-/inter-genus co-culture, and microbial consortia on clubroot disease, plant growth, and rhizosphere bacterial diversity in a field experiment. This study showed that the application of microbial consortia efficiently controls the incidence of clubroot disease with a biocontrol effect of about 65.78% by decreasing the soil acidity and enhancing the yield (2909.8 Kg/666.67 m2). Alleviation of soil acidity results in the abundance and improved activity of beneficial microorganisms in the rhizosphere soil of Chinese cabbage. High throughput sequencing results demonstrated that bacterial phyla Proteobacteria, Bacteroidetes, and Firmicutes were present in high relative abundance in the rhizosphere soil of Chinese cabbage. The application of microbial consortia recovers the imbalance of indigenous micro-ecology and alters the diversity and structure of rhizosphere bacterial communities. Therefore, we conclude that microbial consortia can reduce the clubroot incidence on Chinese cabbage by reshaping the rhizosphere microbiome and decreasing the soil acidity. This study suggested microbial consortia as a new engineering tool to control devastating soilborne disease in commercial crops.

Biocontrol of clubroot disease: how successful are endophytic fungi and bacteria?

“…As long as the organisms are not persistent in the field or their application is expensive and economically unfeasible, the BCA-based measures will not provide value over traditional control methods. Another promising approach is to use microbial consortia in the field against clubroot (Niu et al, 2020;Zhang et al, 2022). It will remain crucial to maintain soil health, nutrient availability and good soil structure for optimal plant growth and efficient recruitment of plants for the endophytes that will benefit the plant.…”

“…The phytobiome of host plants as well as the soil microbial diversity influences the efficacy of biocontrol and likely the mechanisms involved (Daval et al, 2020;Yu et al, 2015;Zhang et al, 2022;Zhao et al, 2017). For example, Trichoderma harzianum isolates were able to increase the number of Bacillus strains in the rhizosphere of Chinese cabbage that reduced clubroot incidences (Li et al, 2020) and which may contribute via antibiosis and / or defense priming to clubroot tolerance (Lahlali et al, 2011.…”