Abstract
Many types of symptoms associated with discolored grain have been observed on rice (Oryza sativa) sheaths, leaves, and grain in Mexico, Guatemala, Panama, Surinam, Colombia, Peru, and Brazil. These include brown necrotic lesions ranging from small specks to large brown to maroon sheath blotches. Symptoms were also expressed as a brown stripe on the sheath that could extend along the midrib of the leaf lamina for nearly its entire length. Panicles failed to emerge properly from the boot when the flag leaf sheath was severely affected, producing discolored and poorly filled grain. Grain from panicles of badly affected plants showed variable severity of symptom expression. A fluorescent pseudomonad was consistently isolated from affected tissue collected in Colombia and Surinam and reproduced symptoms upon inoculation. The pathogen was identified as Pseudomonas fuscovaginae, the causal agent of bacterial sheath brown rot of rice first described in Japan. Comparison of the physiological characteristics of isolates from Latin America, Asia, and Africa, P. fuscovaginae, and P. marginalis suggests that the designation of P. fuscovaginae as a separate species may not be appropriate. The bacterium was seed-transmitted, with seedlings showing symptoms on sheaths and leaves after 10–20 days. Heat treatment at 65 C for 6 days eradicated the pathogen from infected seed. The possibility that this pathogen is a principal causal agent of the dirty panicle disease (grain spotting, manchado de grano) is discussed.
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Claims 7
Claim · model-written summary
Rice sheath brown rot included necrotic sheath lesions and a stripe extending along the leaf midrib.
- Taxon
- rice
Oryza sativat0 - Outcome
- brown necrotic lesionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These include brown necrotic lesions ranging from small specks to large brown to maroon sheath blotches. Symptoms were also expressed as a brown stripe on the sheath that could extend along the midrib of the leaf lamina for nearly its entire length.”
t0“Bacterial Sheath Brown Rot of Rice”
Claim · model-written summary
Severely affected rice flag leaf sheaths were associated with poor panicle emergence and discolored, poorly filled grain.
- Taxon
- riceOryza sativat0
- Outcome
- Panicles failed to emerge properlye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Panicles failed to emerge properly from the boot when the flag leaf sheath was severely affected, producing discolored and poorly filled grain.”
t0“Bacterial Sheath Brown Rot of Rice”
Claim · model-written summary
A fluorescent pseudomonad from affected rice tissue reproduced symptoms after inoculation.
- Taxon
- riceOryza sativat0
- Treatment
- inoculatione0
- Interactor
- fluorescent pseudomonade0pathogen
- Outcome
- reproduced symptomse0
- Setting
- Colombia and Suriname0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A fluorescent pseudomonad was consistently isolated from affected tissue collected in Colombia and Surinam and reproduced symptoms upon inoculation.”
t0“Bacterial Sheath Brown Rot of Rice”
Claim · model-written summary
The rice sheath brown rot pathogen was identified as Pseudomonas fuscovaginae.
- Taxon
- riceOryza sativae0
- Interactor
- Pseudomonas fuscovaginaePseudomonas aspleniie0pathogen
- Outcome
- bacterial sheath brown rot of ricee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The pathogen was identified as Pseudomonas fuscovaginae, the causal agent of bacterial sheath brown rot of rice first described in Japan.”
Claim · model-written summary
Physiological comparisons raised doubt that P. fuscovaginae merits separate species status.
- Taxon
- riceOryza sativat0
- Interactor
- P. fuscovaginaePseudomonas aspleniie0pathogen
- Outcome
- designation of P. fuscovaginae as a separate species may not be appropriatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Comparison of the physiological characteristics of isolates from Latin America, Asia, and Africa, P. fuscovaginae, and P. marginalis suggests that the designation of P. fuscovaginae as a separate species may not be appropriate.”
t0“Bacterial Sheath Brown Rot of Rice”
Claim · model-written summary
The bacterium was transmitted through rice seed, and seedlings showed symptoms after 10–20 days.
- Taxon
- riceOryza sativat0
- Outcome
- seedlings showing symptoms on sheaths and leavese0
- Value
- 10–20 dayse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The bacterium was seed-transmitted, with seedlings showing symptoms on sheaths and leaves after 10–20 days.”
t0“Bacterial Sheath Brown Rot of Rice”
Claim · model-written summary
Heat treatment at 65 C for 6 days eradicated the pathogen from infected rice seed.
- Taxon
- riceOryza sativat0
- Treatment
- Heat treatment at 65 C for 6 dayse0
- Interactor
- pathogene0pathogen
- Outcome
- eradicated the pathogen from infected seede0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Heat treatment at 65 C for 6 days eradicated the pathogen from infected seed.”
t0“Bacterial Sheath Brown Rot of Rice”
The same questions in other papers
inoculation · disease · Oryza sativa (rice)Positive and negative results
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