Abstract
ABSTRACT Black shank disease in tobacco, caused by Phytophthora nicotianae , can lead to yield losses of 30%–50% upon outbreak. Recently, biochar derived from agricultural waste has shown significant potential in controlling soil-borne diseases, though its mechanisms remain unclear. Over a 3-year observation period, we found that the incidence of black shank was significantly lower in plots amended with biochar compared with normal cultivation plots. To investigate the underlying mechanisms, we studied both the direct and indirect effects of biochar on black shank. Direct antifungal assays indicated that biochar reduced the total number of sporangia by 53.91%. Further pot experiments revealed a 62.34% reduction in the P. nicotianae population in the soil following biochar application. Additionally, biochar application led to notable changes in soil physicochemical properties and microbial community composition. Microbial species analysis showed that biochar promoted the aggregation of beneficial microbes such as Sphingomonas , Flavisolibacter , and Mucoromycota . Functional predictions using the PICRUSt 2 software revealed that biochar enhances bacterial functions related to antimicrobial substance synthesis (Tetracycline biosynthesis), detoxification metabolism (D-arginine and D-ornithine metabolism, arginine and proline metabolism), and lipid and fatty acid metabolism (Lipopolysaccharide biosynthesis, fatty acid biosynthesis), while fungal functions showed no significant changes. This suggests that rhizosphere bacteria play a more prominent role in the suppression of black shank by biochar, a finding supported by partial least squares path modeling analysis. Therefore, we hypothesize that biochar not only directly inhibits P. nicotianae growth but also regulates the composition of the rhizosphere microbial community, inducing the production of antimicrobial substances by rhizosphere bacteria, effectively preventing P. nicotianae invasion. IMPORTANCE Black shank, a global soil-borne fungal disease in tobacco, currently lacks effective control methods. Notably, biochar derived from agricultural waste has shown significant potential in controlling soil-borne diseases. Over a 3-year observation period, we found that plots amended with biochar had a significantly lower incidence of black shank compared with normal cultivation plots. However, the mechanisms of disease suppression remained unclear. Through in vitro antifungal assays and pot experiments, we discovered that tobacco-derived biochar can directly inhibit the growth of the pathogen. Additionally, biochar regulates the composition of the rhizosphere microbial community, inducing rhizosphere bacteria to produce antimicrobial substances, effectively preventing pathogen invasion. This discovery reveals both the direct and indirect mechanisms by which biochar suppresses black shank in tobacco. It provides a scientific basis for developing green control technologies for black shank and offers theoretical support for the application of biochar in managing soil-borne diseases in tobacco cultivation areas.
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Claims 15
Claim · model-written summary
Biochar-amended plots had significantly less tobacco black shank than normal cultivation plots.
- Taxon
- tobacco
Nicotiana tabacumt0 - Treatment
- biochare0
- Outcome
- incidence of black shanke0
- Direction
- lowere0
- Comparator
- normal cultivation plotse0
Not reportedInteractor
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the incidence of black shank was significantly lower in plots amended with biochar compared with normal cultivation plots.”
t0“tobacco”
Claim · model-written summary
Biochar reduced Phytophthora nicotianae sporangia by 53.91% in direct assays.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Outcome
- total number of sporangiae0
- Direction
- reducede0
- Value
- 53.91%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Direct antifungal assays indicated that biochar reduced the total number of sporangia by 53.91%.”
t0“tobacco”
Claim · model-written summary
Biochar application reduced soil P. nicotianae populations by 62.34% in pots.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochar applicatione0
- Interactor
- P. nicotianae
Phytophthora nicotianaee0pathogen - Outcome
- P. nicotianae population in the soile0
- Direction
- reductione0
- Value
- 62.34%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Further pot experiments revealed a 62.34% reduction in the P. nicotianae population in the soil following biochar application.”
t0“tobacco”
Claim · model-written summary
Biochar changed soil physicochemical properties.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochar applicatione0
- Outcome
- soil physicochemical propertiese0
- Direction
- changese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar application led to notable changes in soil physicochemical properties and microbial community composition.”
t0“tobacco”
Claim · model-written summary
Biochar changed soil microbial community composition.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochar applicatione0
- Outcome
- microbial community compositione0
- Direction
- changese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar application led to notable changes in soil physicochemical properties and microbial community composition.”
t0“tobacco”
Claim · model-written summary
Biochar promoted Sphingomonas aggregation.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Interactor
- Sphingomonas
Sphingomonase0symbiont - Outcome
- aggregation of beneficial microbese0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar promoted the aggregation of beneficial microbes such as Sphingomonas , Flavisolibacter , and Mucoromycota .”
t0“tobacco”
Claim · model-written summary
Biochar promoted Flavisolibacter aggregation.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Interactor
- FlavisolibacterFlavisolibactere0symbiont
- Outcome
- aggregation of beneficial microbese0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar promoted the aggregation of beneficial microbes such as Sphingomonas , Flavisolibacter , and Mucoromycota .”
t0“tobacco”
Claim · model-written summary
Biochar promoted Mucoromycota aggregation.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Interactor
- MucoromycotaMucoromycotae0symbiont
- Outcome
- aggregation of beneficial microbese0
- Direction
- promotede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar promoted the aggregation of beneficial microbes such as Sphingomonas , Flavisolibacter , and Mucoromycota .”
t0“tobacco”
Claim · model-written summary
Predicted bacterial tetracycline biosynthesis increased with biochar.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Outcome
- Tetracycline biosynthesise0
- Direction
- enhancese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar enhances bacterial functions related to antimicrobial substance synthesis (Tetracycline biosynthesis)”
t0“tobacco”
Claim · model-written summary
Predicted bacterial detoxification metabolism increased with biochar.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Outcome
- detoxification metabolisme0
- Direction
- enhancese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar enhances bacterial functions related to antimicrobial substance synthesis (Tetracycline biosynthesis), detoxification metabolism (D-arginine and D-ornithine metabolism, arginine and proline metabolism)”
t0“tobacco”
Claim · model-written summary
Predicted bacterial lipid and fatty acid metabolism increased with biochar.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Outcome
- lipid and fatty acid metabolisme0
- Direction
- enhancese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar enhances bacterial functions related to antimicrobial substance synthesis (Tetracycline biosynthesis), detoxification metabolism (D-arginine and D-ornithine metabolism, arginine and proline metabolism), and lipid and fatty acid metabolism (Lipopolysaccharide biosynthesis, fatty acid biosynthesis)”
t0“tobacco”
Claim · model-written summary
Predicted fungal functions showed no significant changes under biochar.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare1
- Outcome
- fungal functionse0
- Direction
- no significant changese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fungal functions showed no significant changes.”
t0“tobacco”
e1“the incidence of black shank was significantly lower in plots amended with biochar compared with normal cultivation plots.”
Claim · model-written summary
The authors infer that rhizosphere bacteria are more important in biochar suppression of black shank.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Outcome
- suppression of black shanke0
- Qualifier
- rhizosphere bacteriae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“rhizosphere bacteria play a more prominent role in the suppression of black shank by biochar”
t0“tobacco”
Claim · model-written summary
The authors hypothesize that biochar directly inhibits P. nicotianae growth.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- biochare0
- Interactor
- P. nicotianaePhytophthora nicotianaee0pathogen
- Outcome
- P. nicotianae growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“biochar not only directly inhibits P. nicotianae growth but also regulates the composition of the rhizosphere microbial community”
t0“tobacco”
Claim · model-written summary
The authors hypothesize that biochar regulates the rhizosphere community to induce antimicrobial substance production and prevent pathogen invasion.
- Taxon
- tobaccoNicotiana tabacumt0
- Interactor
- P. nicotianaePhytophthora nicotianaee0pathogen
- Outcome
- P. nicotianae invasione0
- Qualifier
- production of antimicrobial substances by rhizosphere bacteriae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“regulates the composition of the rhizosphere microbial community, inducing the production of antimicrobial substances by rhizosphere bacteria, effectively preventing P. nicotianae invasion.”
t0“tobacco”
The same questions in other papers
biochar · Phytophthora nicotianae · Nicotiana tabacum (tobacco)Results agree
2 papers in the same direction as this paper
- positive
- positive
biochar · disease · Nicotiana tabacum (tobacco)Results agree
2 papers in the same direction as this paper
- positive
- positive
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.