Abstract
Rice blast and brown spot are two of the most significant fungal diseases affecting rice production. Although the leaf symptoms of both diseases are distinct, they manifest as similar brown-black lesions, complicating differentiation and effective management. Traditional diagnostic methods predominantly rely on DNA-based molecular techniques, which are not well-suited for rapid, large-scale applications. This study aimed to identify reliable chlorophyll fluorescence (ChlF) indicators for diagnosing these diseases at the pre-symptomatic stage using a pulse-amplitude modulation fluorometer. Changes in ChlF parameters were measured following fungal infection in 120 leaves and 750 spots across five time points in detached leaf assays. Diagnostic indicators were selected through machine learning and fold-change value comparisons, then validated using 374 pre-symptomatic spots induced under different infection conditions in whole plants. Fifteen ChlF diagnostic parameters were identified, nine of which were specifically associated with rice blast. Pre-symptomatic lesions in both diseases caused significant decreases in non-photochemical quenching parameters ( NPQ_D1 / D2 and qN_D1 / D2 / D3 ), while simultaneous increases in photochemical quenching parameters ( qL_L2 / L3 , qP_L2 / L3 / L4 , and QY_L2 / L3 / L4 ) were observed only in rice blast. The vitality index R fd _L2 exhibited a notable increase in both diseases. However, a consistent decrease in F t _L2 , necessary for calculating R fd _L2 , was observed only in rice blast, indicating different pathogenic mechanisms despite similar visible symptoms. Our results suggest that these ChlF parameters can serve as powerful diagnostic indicators for rice fungal diseases, and that ChlF imaging offers a straightforward approach for plant disease diagnosis.
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Claims 7
Claim · model-written summary
Fifteen chlorophyll fluorescence diagnostic parameters were identified for pre-symptomatic rice blast and brown spot.
- Taxon
- rice
Oryza sativae0 - Outcome
- ChlF diagnostic parameterse0
- Value
- Fifteene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fifteen ChlF diagnostic parameters were identified, nine of which were specifically associated with rice blast”
Claim · model-written summary
Nine of the fifteen chlorophyll fluorescence diagnostic parameters were specifically associated with rice blast.
- Taxon
- riceOryza sativae0
- Outcome
- specifically associated with rice blaste0
- Value
- ninee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fifteen ChlF diagnostic parameters were identified, nine of which were specifically associated with rice blast”
Claim · model-written summary
Pre-symptomatic lesions of both rice blast and brown spot caused significant decreases in non-photochemical quenching parameters.
- Taxon
- riceOryza sativat0
- Outcome
- non-photochemical quenching parameterse0
- Direction
- decreasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pre-symptomatic lesions in both diseases caused significant decreases in non-photochemical quenching parameters”
t0“rice blast and brown spot diseases”
Claim · model-written summary
Photochemical quenching parameters increased in pre-symptomatic lesions only in rice blast.
- Taxon
- riceOryza sativae0
- Outcome
- photochemical quenching parameterse0
- Direction
- increasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increases in photochemical quenching parameters ( qL_L2 / L3 , qP_L2 / L3 / L4 , and QY_L2 / L3 / L4 ) were observed only in rice blast”
Claim · model-written summary
The vitality index Rfd_L2 increased notably in both rice blast and brown spot.
- Taxon
- riceOryza sativat0
- Outcome
- vitality index R fd _L2e0
- Direction
- increasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The vitality index R fd _L2 exhibited a notable increase in both diseases”
t0“rice blast and brown spot diseases”
Claim · model-written summary
A consistent decrease in Ft_L2 was observed only in rice blast.
- Taxon
- riceOryza sativae0
- Outcome
- F t _L2e0
- Direction
- decreasee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a consistent decrease in F t _L2 , necessary for calculating R fd _L2 , was observed only in rice blast”
Claim · model-written summary
The authors suggest these ChlF parameters can serve as diagnostic indicators for rice fungal diseases.
- Taxon
- riceOryza sativae0
- Outcome
- diagnostic indicators for rice fungal diseasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“these ChlF parameters can serve as powerful diagnostic indicators for rice fungal diseases”