Natural and Substrate-induced Microbial Succession and its Impact on Verticillium Wilt

Authors: MANDAL, MIHIR - University Of California; PURI, KRISHNA - University Of California; SUREN, HAKTAN - University Of California; Henry, Peter; INDERBITZIN, PATRIK - University Of California; CHELLEMI, DAN - University Of California; SUBBARAO, KRISHNA - University Of California

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/26/2023
Publication Date: 8/12/2023
Citation: Mandal, M.K., Puri, K.D., Suren, H., Henry, P.M., Inderbitzin, P., Chellemi, D.O., Subbarao, K.V. 2023. Natural and substrate-induced microbial succession and its impact on Verticillium wilt. American Phytopathological Society Annual Meeting, August 12-16, 2023, Denver, Colorado.

Interpretive Summary:

Technical Abstract: Verticillium wilt caused by Verticillium dahliae, is a significant disease of many high-value crops worldwide. The ability to harness native soil microbiomes to manage Verticillium wilt remains a promising but relatively unexplored area. We investigated the natural and amendment-induced microbial (fungal and bacterial) succession patterns in three soils with distinct land-use histories (agricultural soil subjected to decades of soil fumigation A; native, undisturbed soil B; and soil C - in transition from pasture to organic agriculture). We compared the effect of broccoli residue, crustacean meal and unamended soils for changes in soil microbiomes using high-throughput sequencing of ITS and 16S rRNA genes to identify soil microbiota associated with Verticillium wilt suppression. Prokaryotic richness, diversity, and abundance was highest in Soil B followed by Soil C and Soil A; whereas fungal diversity was highest in Soil C followed by Soil B and Soil A. Verticillium wilt severity on eggplant and microsclerotia density were lowest in Soil C followed by Soil A and Soil B. The broccoli and broccoli-crustacean amended soil had the higher alpha diversity and reduced wilt disease severity relative to crustacean or unamended soil types. The Verticillium wilt reductions were correlated with significant enrichment of antagonists in Bacillaceae (Soil B), Myxococcaceae (Soil A) and Pseudomonadaceae (Soil C) in the broccoli and broccoli-crustacean amended soils. Fungal species associated with wilt suppression were also soil-specific. Thus, substrate-mediated shifts in native microbiomes antagonistic to V. dahliae can convert Verticillium wilt-conducive soils to Verticillium wilt-suppressive soils regardless of the soil type.