Abstract
Larix olgensis, a keystone timber species in Northeast China, is increasingly threatened by Neofusicoccum laricinum-induced shoot blight, a devastating disease that compromises forest health and necessitates sustainable management strategies. Here, we demonstrate that the endophytic bacterium Bacillus amyloliquefaciens JL54 elicits multifaceted defense responses in L. olgensis, enhancing resistance to pathogen infection. Greenhouse assays revealed that JL54 pretreatment reduced disease incidence by 12.5% and achieved 43.75% control efficacy while maintaining host vigor. Histochemical analyses identified JL54-induced rapid hydrogen peroxide (H2O2) accumulation, extensive lignin deposition, and localized programmed cell death (PCD), indicative of a primed immune response. Transcriptomic analyses uncovered distinct temporal defense patterns: early-stage responses (0 h post-inoculation) were characterized by upregulation of cutin, suberin, and wax biosynthesis pathways, reinforcing physical barriers, whereas late-stage responses (12 h post-inoculation) were dominated by ribosome- and proteostasis-related pathways (e.g., heat shock proteins [HSPs], glutathione S-transferases [GSTs]) to mitigate cellular damage. Biochemical assays corroborated these findings, with JL54 colonization reducing membrane lipid peroxidation (27.2% decrease in malondialdehyde content) and significantly elevating the activity of key defense enzymes, including peroxidase (POD), phenylalanine ammonia-lyase (PAL), and GST. Phytohormone profiling implicated jasmonic acid (JA) as the central mediator of induced systemic resistance (ISR), with JL54-potentiated JA signaling preceding pathogen containment. Collectively, these results demonstrate that JL54 contributes to a coordinated defense strategy in L. olgensis, integrating structural reinforcement (cuticle/lignin), oxidative stress management, and JA-mediated immune priming. These insights advance the understanding of endophyte-conferred resistance in conifers and highlight JL54’s potential as a biocontrol agent for sustainable forestry.
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Claims 9
Claim · model-written summary
JL54 pretreatment reduced shoot blight disease incidence in Larix by 12.5%.
- Taxon
- Larix olgensis
Larix gmelinii var. olgensise1 - Treatment
- JL54 pretreatmente0
- Interactor
- Neofusicoccum laricinumNeofusicoccum laricinume1pathogen
- Second interactor
- Bacillus amyloliquefaciens JL54
.jpg?width=60)
Bacillus amyloliquefaciense2biocontrol_agent - Outcome
- disease incidencee0
- Direction
- reducede0
- Value
- 12.5%e0
- Setting
- Greenhousee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Greenhouse assays revealed that JL54 pretreatment reduced disease incidence by 12.5% and achieved 43.75% control efficacy while maintaining host vigor”
e1“Larix olgensis, a keystone timber species in Northeast China, is increasingly threatened by Neofusicoccum laricinum-induced shoot blight”
e2“Bacillus amyloliquefaciens JL54”
Claim · model-written summary
JL54 pretreatment achieved 43.75% shoot blight control efficacy in Larix.
- Taxon
- Larix olgensisLarix gmelinii var. olgensise1
- Treatment
- JL54 pretreatmente0
- Interactor
- Neofusicoccum laricinumNeofusicoccum laricinume1pathogen
- Second interactor
- Bacillus amyloliquefaciens JL54Bacillus amyloliquefaciense2biocontrol_agent
- Outcome
- control efficacye0
- Direction
- achievede0
- Value
- 43.75%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Greenhouse assays revealed that JL54 pretreatment reduced disease incidence by 12.5% and achieved 43.75% control efficacy while maintaining host vigor”
e1“Larix olgensis, a keystone timber species in Northeast China, is increasingly threatened by Neofusicoccum laricinum-induced shoot blight”
e2“Bacillus amyloliquefaciens JL54”
Claim · model-written summary
JL54 pretreatment maintained Larix host vigor.
- Taxon
- Larix olgensisLarix gmelinii var. olgensise1
- Treatment
- JL54 pretreatmente0
- Outcome
- host vigore0
- Direction
- maintaininge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“JL54 pretreatment reduced disease incidence by 12.5% and achieved 43.75% control efficacy while maintaining host vigor”
e1“Larix olgensis”
Claim · model-written summary
JL54 induced rapid H2O2 accumulation, lignin deposition and localized programmed cell death in Larix.
- Taxon
- Larix olgensisLarix gmelinii var. olgensise1
- Treatment
- JL54e0
- Outcome
- hydrogen peroxide (H2O2) accumulation, extensive lignin deposition, and localized programmed cell death (PCD)e0
- Direction
- accumulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“JL54-induced rapid hydrogen peroxide (H2O2) accumulation, extensive lignin deposition, and localized programmed cell death (PCD)”
e1“Larix olgensis”
Claim · model-written summary
At 0 h post-inoculation, Larix defense showed upregulation of cutin, suberin and wax biosynthesis pathways.
- Taxon
- Larix olgensisLarix gmelinii var. olgensise1
- Outcome
- cutin, suberin, and wax biosynthesis pathwayse0
- Direction
- upregulatione0
- Qualifier
- 0 h post-inoculatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“early-stage responses (0 h post-inoculation) were characterized by upregulation of cutin, suberin, and wax biosynthesis pathways”
e1“Larix olgensis”
Claim · model-written summary
At 12 h post-inoculation, Larix responses were dominated by ribosome and proteostasis related pathways.
- Taxon
- Larix olgensisLarix gmelinii var. olgensise1
- Outcome
- ribosome- and proteostasis-related pathwayse0
- Direction
- dominatede0
- Qualifier
- 12 h post-inoculatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“late-stage responses (12 h post-inoculation) were dominated by ribosome- and proteostasis-related pathways (e.g., heat shock proteins [HSPs], glutathione S-transferases [GSTs])”
e1“Larix olgensis”
Claim · model-written summary
JL54 colonization reduced Larix malondialdehyde content by 27.2%.
- Taxon
- Larix olgensisLarix gmelinii var. olgensise1
- Treatment
- JL54 colonizatione0
- Outcome
- malondialdehyde contente0
- Direction
- decreasee0
- Value
- 27.2%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“JL54 colonization reducing membrane lipid peroxidation (27.2% decrease in malondialdehyde content)”
e1“Larix olgensis”
Claim · model-written summary
JL54 colonization significantly increased POD, PAL and GST defense enzyme activities in Larix.
- Taxon
- Larix olgensisLarix gmelinii var. olgensise1
- Treatment
- JL54 colonizatione0
- Outcome
- activity of key defense enzymes, including peroxidase (POD), phenylalanine ammonia-lyase (PAL), and GSTe0
- Direction
- elevatinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“JL54 colonization reducing membrane lipid peroxidation (27.2% decrease in malondialdehyde content) and significantly elevating the activity of key defense enzymes, including peroxidase (POD), phenylalanine ammonia-lyase (PAL), and GST”
e1“Larix olgensis”
Claim · model-written summary
Phytohormone profiling implicated JA signaling as central to JL54-induced systemic resistance and preceding pathogen containment.
- Taxon
- Larix olgensisLarix gmelinii var. olgensise1
- Compound
- jasmonic acid (JA)e0
- Outcome
- induced systemic resistance (ISR)e0
- Qualifier
- JL54-potentiated JA signaling preceding pathogen containmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phytohormone profiling implicated jasmonic acid (JA) as the central mediator of induced systemic resistance (ISR), with JL54-potentiated JA signaling preceding pathogen containment”
e1“Larix olgensis”