Abstract
Early diagnosis technology is crucial for early warning and control of pine wilt disease (PWD), a devastating forest disease. However, current methods rely largely on external symptoms and are infective during the asymptomatic stage. This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN). The feasibility of applying infrared spectroscopy for early PWD diagnosis was further validated through negative controls and chemometric models. The results revealed an approximately two-week asymptomatic diagnostic window following infection. ATR-FTIR spectroscopy enabled earlier detection than measurements of needle water content or relative conductivity. Furthermore, ATR-FTIR spectroscopy distinguished nematode stress from drought stress based on differential trends at 2908 and 2840 cm⁻¹ and in full-spectrum integrated area. Derivative spectra further revealed multiple early-stage characteristics. Exploratory analysis of all stages using PCA and PLS-DA indicated that simultaneous multi-stage discrimination was not feasible due to weak early-stage signals and severe overlap between Stage 0 and Stage I (test-set accuracy: 30.5%). Focusing specially on Stage 0 and Stage I to construct an OPLS-DA model, test-set performance improved to an accuracy of 85.2%, a sensitivity of 85.7%, a specificity of 84.6%, and an AUC of 0.879 (95% CI: 0.741, 0.992). The permutation test was statistically significant (p = 0.0050). VIP analysis identified nine markers with scores ≥ 1.0 indicating that PC1 and raw spectral features drove discrimination synergistically. Univariate testing revealed that only A11_Peak_1278_existence was statistically significant confirming that Stage I was characterized by the superposition of weak multivariate signals. In summary, coordinated changes across multiple peaks and the distinctive decrease-increase-stabilize-decrease pattern observed in certain peaks constitute a unique spectral signature of PWD. Infrared spectroscopy can detect subtle anomalies in 3-year-old P. thunbergii seedlings infected with pine wood nematode while needles remain asymptomatic, water content changes are still insignificant, and cell membrane function has not yet been extensively compromised. This finding demonstrates significant potential for early PWD diagnosis.
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Claims 16
Claim · model-written summary
An approximately two-week asymptomatic diagnostic window follows pine wood nematode infection in P. thunbergii seedlings.
- Taxon
- Pinus thunbergii
Pinus thunbergiie1 - Interactor
- pine wood nematode
Bursaphelenchus xylophiluse1pathogen - Outcome
- asymptomatic diagnostic windowe2
- Value
- approximately two-weeke2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“The results revealed an approximately two-week asymptomatic diagnostic window following infection”
Claim · model-written summary
ATR-FTIR spectroscopy enabled earlier detection of infection than needle water content or relative conductivity.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- earlier detectione2
- Comparator
- needle water content or relative conductivitye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“ATR-FTIR spectroscopy enabled earlier detection than measurements of needle water content or relative conductivity”
Claim · model-written summary
ATR-FTIR distinguished nematode stress from drought stress using differential trends at 2908 and 2840 cm⁻¹ and in full-spectrum integrated area.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- differential trends at 2908 and 2840 cm⁻¹e2
- Comparator
- drought stresse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“ATR-FTIR spectroscopy distinguished nematode stress from drought stress based on differential trends at 2908 and 2840 cm⁻¹ and in full-spectrum integrated area”
Claim · model-written summary
PCA and PLS-DA across all stages gave a test-set accuracy of 30.5%, so simultaneous multi-stage discrimination was not feasible.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- test-set accuracye2
- Value
- 30.5%e2
- Qualifier
- weak early-stage signals and severe overlap between Stage 0 and Stage Ie2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“Exploratory analysis of all stages using PCA and PLS-DA indicated that simultaneous multi-stage discrimination was not feasible due to weak early-stage signals and severe overlap between Stage 0 and Stage I (test-set accuracy: 30.5%)”
Claim · model-written summary
The OPLS-DA model for Stage 0 and Stage I reached a test-set accuracy of 85.2%.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- accuracye2
- Value
- 85.2%e2
- Qualifier
- OPLS-DA modele2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“Focusing specially on Stage 0 and Stage I to construct an OPLS-DA model, test-set performance improved to an accuracy of 85.2%”
Claim · model-written summary
The OPLS-DA model for Stage 0 and Stage I reached a sensitivity of 85.7%.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- sensitivitye2
- Value
- 85.7%e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“a sensitivity of 85.7%”
Claim · model-written summary
The OPLS-DA model for Stage 0 and Stage I reached a specificity of 84.6%.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- specificitye2
- Value
- 84.6%e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“a specificity of 84.6%”
Claim · model-written summary
The OPLS-DA model for Stage 0 and Stage I reached an AUC of 0.879.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- AUCe2
- Value
- 0.879e2
- Qualifier
- 95% CI: 0.741, 0.992e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“an AUC of 0.879 (95% CI: 0.741, 0.992)”
Claim · model-written summary
The permutation test of the model was statistically significant.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- permutation teste2
- Value
- p = 0.0050e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“The permutation test was statistically significant (p = 0.0050)”
Claim · model-written summary
VIP analysis identified nine markers with scores ≥ 1.0, driven by PC1 and raw spectral features.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- markers with scores ≥ 1.0e2
- Value
- nine markerse2
- Qualifier
- PC1 and raw spectral features drove discrimination synergisticallye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“VIP analysis identified nine markers with scores ≥ 1.0 indicating that PC1 and raw spectral features drove discrimination synergistically”
Claim · model-written summary
In univariate tests only the A11_Peak_1278_existence variable was statistically significant.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- A11_Peak_1278_existencee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“Univariate testing revealed that only A11_Peak_1278_existence was statistically significant”
Claim · model-written summary
A decrease-increase-stabilize-decrease pattern in certain peaks, together with coordinated changes across peaks, is a unique spectral signature of PWD.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- decrease-increase-stabilize-decrease patterne2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“coordinated changes across multiple peaks and the distinctive decrease-increase-stabilize-decrease pattern observed in certain peaks constitute a unique spectral signature of PWD”
Claim · model-written summary
Infrared spectroscopy can detect subtle anomalies in P. thunbergii seedlings infected with pine wood nematode while needles remain asymptomatic.
- Taxon
- P. thunbergiiPinus thunbergiie2
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- subtle anomaliese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“Infrared spectroscopy can detect subtle anomalies in 3-year-old P. thunbergii seedlings infected with pine wood nematode while needles remain asymptomatic”
Claim · model-written summary
Derivative spectra revealed multiple early-stage characteristics of infection.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- multiple early-stage characteristicse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“Derivative spectra further revealed multiple early-stage characteristics”
Claim · model-written summary
Needle water content changes were still insignificant in infected seedlings during the asymptomatic stage.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- water content changese2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“water content changes are still insignificant”
Claim · model-written summary
Cell membrane function had not yet been extensively compromised in infected seedlings during the asymptomatic stage.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Interactor
- pine wood nematodeBursaphelenchus xylophiluse1pathogen
- Outcome
- cell membrane functione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“This study employed 3-year-old Pinus thunbergii seedlings as the experimental materials to compare the timing of anomaly detection in needle water content, relative conductivity (RC), and ATR-FTIR spectroscopy following inoculation with the pine wood nematode (PWN)”
e2“cell membrane function has not yet been extensively compromised”