α-Terpineol fumigation alleviates negative plant-soil feedbacks of Panax notoginseng via suppressing Ascomycota and enriching antagonistic bacteria

Abstract

The accumulation of soil-borne pathogens is the main driving factor of negative plant-soil feedbacks (NPSFs), which seriously restricts the sustainable development of agriculture. Using natural volatile organic compounds (VOCs) from plants or microorganisms as biofumigants is an emerging strategy to alleviate NPSFs in an environmentally-friendly way. Here, we identified α-terpineol from the VOCs of pine needles, confirmed the ability of α-terpineol fumigation in alleviating the NPSF of Panax notoginseng via significantly reducing seed decay rate, and also deciphered the underlying mechanism by which the soil microbial community is modified. α-Terpineol fumigation could suppress culturable fungi but enrich bacteria in a dose-dependent manner. Network analysis with high-throughput sequencing data revealed that α-terpineol could distinctly modify both fungal and bacterial communities. In detail, α-terpineol significantly suppressed the relative abundance of Ascomycota from 64.04 to 32.26%, but enriched the relative abundance of Proteobacteria, Acidobacteria and Actinobacteria. Subnetwork analysis further demonstrated that α-terpineol could directly or indirectly suppress fungal pathogens and enrich plant growth-promoting rhizobacteria (PGPRs). In vitro fumigation and co-culture experiments with culturable isolates validated these findings. The antagonism between beneficial bacteria and pathogens, and the synergistic growth promotion among α-terpineol-enriched bacteria might be involved in soil microbial community assembly. In summary, α-terpineol fumigation could directly or indirectly modify the soil microbial community to alleviate NPSFs, especially by suppressing fungal pathogens and enriching beneficial bacteria. This study suggests that VOCs from natural products are worth developing as biofumigants due to their multiple functions in modifying the soil microbial community.

Autotoxin affects the rhizosphere microbial community structure by influencing the secretory characteristics of grapevine roots

“…Most genera with high abundance in T- 13 C compared to CK- 13 C belonged to the phylum Ascomycota , except for the genus Rhodotorula ( Figure 5C and Supplementary Table 10 ). Many previous studies have demonstrated that most soil-borne pathogens belong to Ascomycota ( Ye et al, 2021 ). Fusarium and Fusicolla can cause soil-borne diseases in plants ( Chen et al, 2020b ).…”

Allyl Isothiocyanate in the Volatiles of Brassica juncea Inhibits the Growth of Root Rot Pathogens of Panax notoginseng by Inducing the Accumulation of ROS

“…Two components, AITC and (Z)-3-hexen-1-ol, were selected to test their antimicrobial activities according to Ye’s method . Briefly, a pathogen mycelial block (5 mm in diameter) was placed in the middle of a Petri dish filled with PDA.…”

“…Two components, AITC and (Z)-3-hexen-1-ol, were selected to test their antimicrobial activities according to Ye's method. 21 Briefly, a pathogen mycelial block (5 mm in diameter) was placed in the middle of a Petri dish filled with PDA. Then, a sterilized centrifuge tube lid containing AITC or (Z)-3-hexen-1-ol was placed on the cover of the Petri dish with Parafilm.…”

2,3-Butanediol from the leachates of pine needles induces the resistance of Panax notoginseng to the leaf pathogen Alternaria panax

“…Many mechanisms, including plant–plant interactions and plant-insect/pathogen interactions, are involved in disease suppression in biologically diverse ecosystems ( Poelman et al., 2008 ; Yang et al., 2014 ; Ding et al., 2015 ; Pelissier et al., 2021 ). Among them, plants utilize allelochemicals, including volatile organic compounds (VOCs), leachates, root exudates and decayed matter, to alter the surrounding environmental conditions, including by inhibiting microbial growth, reducing the fitness of insects or inducing resistance in nearby plants ( Albuquerque et al., 2010 ; Bachheti et al, 2020 ; Chomel et al., 2020 ; Ye et al., 2021 ).…”

“…langbianensis ( Ye et al., 2019 ). The allelopathic effects of VOCs and leachates under pine forest are mainly the result of pine needles, and VOCs released by pine needles can alter the proportion of rhizosphere microorganisms ( Kato-Noguchi et al., 2011 ; Ye et al., 2021 ). The leachates released from or washed off pine needles by rain contain several antimicrobial, defense or growth-regulating compounds ( Zeng and Jia, 2009 ; Verma et al., 2012 ; Venegas-Molina et al., 2021 ).…”