Targeted isolation of biocontrol agents from plants through phytopathogen co-culture and pathogen enrichment

Abstract

In a long-term symbiotic relationship between plants and pathogens, plants have evolved to harbor beneficially endophytic microbiomes, thereby conferring them the ability to resist infection by pathogens. This prompted us to establish a phytopathogen-based co-culture platform for the targeted isolation of potential biocontrol agents from plants via specific pathogen enrichment. In this study, we investigated three different phytopathogenic systems, including kiwifruit, turfgrass, and rice, and their infectious bacterial and/or fungal pathogens. By using the developed mono- or co-enrichment platform, we efficiently isolated three antimicrobial agents, including Bacillus safensis ZK-1 against Pseudomonas syringae pv. actinidiae that causes kiwifruit canker, Pseudomonas alcaligenes ZK-2 against Clarireedia paspali that causes dollar spot disease in turfgrass, and Bacillus velezensis ZK-3 against rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae and rice blast fungus Magnaporthe oryzae. We believe that the phytopathogenic co-culture and pathogen enrichment platform developed here is versatile and effective for the isolation of potential biocontrol agents with specific or broad-spectrum antimicrobial activities from plants of interest in a targeted and large-scale manner.

Assembly of an active microbial consortium by engineering compatible combinations containing foreign and native biocontrol bacteria of kiwifruit

“…Unlike OH11, ZK-1 efficiently kills Pseudomonas syringae pv. actinidiae ( Psa ) that causes kiwifruit bacterial canker but has weak antifungal activity, as previously reported [22] , [23] . Since the field production of kiwifruit is also severely threatened by several fungal pathogens represented by Diaporthe actinidiae , Colletotrichum gloeosporioides , and Alternaria alternate, which cause kiwifruit soft rot, anthracnose, and brown spot diseases, respectively [24] , [25] , [26] , we therefore aimed to assemble a functional consortium comprising OH11 and ZK-1 to achieve the coordinated control of bacterial and fungal diseases of kiwifruit.…”

“…B . safensis ZK-1 is a Gram-positive biocontrol bacterium isolated from kiwifruit fruit [22] . Unlike OH11, ZK-1 efficiently kills Pseudomonas syringae pv.…”

Adapting the inoculation methods of kiwifruit canker disease to identify efficient biocontrol bacteria from branch microbiome

“…The targeted isolation strategy was designed based on our previous study (Wang, Li, et al., 2022 ). GFP‐tagged Psa was plated on LB agar and incubated at 28°C for 48 h. An agar block with GFP‐tagged Psa was cut and put into kiwifruit branches with a wound.…”

“…The diffusible antibiotics assays were based on our previous study (Wang, Li, et al., 2022 ). In brief, for diffusible antibiotics assays, 1 mL of overnight culture of Psa was mixed with 50 mL of molten peptone sucrose agar (10 g bacteriological peptone, 10 g sucrose, 15 g agar, in 1 L) and poured into a Petri dish.…”

Antibiotic Resistance in Plant Pathogenic Bacteria: Recent Data and Environmental Impact of Unchecked Use and the Potential of Biocontrol Agents as an Eco-Friendly Alternative

“…actinidiae , Pseudomonas alcaligenes ZK-2 against the turfgrass disease dollar spot pathogen Clarireedia paspali , and Bacillus velezensis ZK-3 against the rice bacterial blight pathogen X. oryzae pv. oryzae and rice blast fungus Magnaporthe oryzae [ 237 ].…”