Foliar pathogen-induced assemblage of beneficial rhizosphere consortia increases plant defense against Setosphaeria turcica

Abstract

Background: Foliar pathogen infection can induce the enrichment of beneficial microbial consortia in plant rhizosphere, but the mechanism for enhanced plant resistance is unclear. Methods: We investigated the effects of foliar pathogen infection on bacterial communities in maize rhizosphere using high throughput sequencing. Results: Maize plants grown in non-sterilized soils displayed stronger defense against the foliar pathogen Setosphaeria turcica than those in sterilized soils. Foliar pathogen infection further triggered the shift in the structure and composition of rhizosphere bacterial communities. The pathogen-infected plants specially promoted rhizosphere colonization of several bacterial taxa. The Pseudomonas genus increased in the rhizosphere after pathogen infection. Other bacterial genera such as Chitinophaga and Flavobacterium were also greatly enriched in the rhizosphere of pathogen-infected plants. Furthermore, the enriched bacterial species were isolated and were shown to interact synergistically to promote biofilm formation. Although both the Chitinophaga and Flavobacterium species did not induce plant defense, the Pseudomonas species markedly increased the resistance of plants against S. turcica. Furthermore, the consortium consisting of the Pseudomonas, Chitinophaga and Flavobacterium species (CONpcf) conferred long-acting disease resistance of maize plants as compared to the individual Pseudomonas species. Furthermore, the inoculation with the CONpcf significantly induced a marked increase in the levels of DIMBOA in maize leaves, indicating that the consortium-induced increases of DIMBOA levels partially contributed to enhancing disease resistance of plants. Conclusions: Foliar infection of maize plants by S. turcica specifically recruited a group of beneficial rhizosphere bacteria, which conferred enhanced plant defense against pathogen infection. This study provided important evidence that above-ground pathogen infection participated in the mediation of below-ground microbiome for regulating plant defense systems.

Pathogen-Mediated Assembly of Plant-Beneficial Bacteria to Alleviate Fusarium Wilt in Pseudostellaria heterophylla

“…Our study found that pathogen-mediated P. heterophylla enriched Pseudomonas in rhizospheric soil and participated in decreasing the incidence of FW. This result is consistent with studies conducted with maize ( Zhu et al, 2021 ), barley ( Schreiner et al, 2010 ; Dudenhffer et al, 2016 ), wheat ( Landa et al, 2002 ), pea ( Landa et al, 2002 ), carnations ( Lemanceau et al, 1992 ), and Panax notoginseng ( Zhang et al, 2020b ). In addition, Pseudomonas was also mediated by pathogens such as Setosphaeria turcica , Gaeumannomyces gramini , and Fusarium spp.…”

“…In addition, Pseudomonas was also mediated by pathogens such as Setosphaeria turcica , Gaeumannomyces gramini , and Fusarium spp. ( Lemanceau et al, 1992 ; Landa et al, 2002 ; Zhang et al, 2020b ; Zhu et al, 2021 ). Furthermore, Pseudomonas was induced by F. oxysporum to colonize on the tuberous roots, which was similar to the results of a previous study showing that leaf pathogens can mediate the colonization of Pseudomonas on Arabidopsis roots ( Léon-Kloosterziel et al, 2005 ).…”