Abstract
Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant. In April 2022, a leaf disease on D. stramonium was observed in Zhanjiang (21.17 N, 110.18 E), Guangdong province, China. Early symptoms were small yellow spots on leaves. Later, the spots gradually expanded and turned becoming necrotic with a clear yellow halo and a white center. The disease incidence in the field was 85% (n = 50, about 1 ha). Twenty diseased leaves were collected from the field. The margin of the diseased tissues was cut into 2 mm × 2 mm pieces, surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, respectively, and rinsed twice with sterile water before isolation. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. After 2-day incubation, grayish fungal colonies appeared on the PDA, then pure cultures were produced by transferring hyphal tips to new PDA plates. Single-spore isolation method was used to recover pure cultures for three isolates (DSAC-1, DSAC-2, and DSAC-3). The isolates were morphologically identical . They colonies were gray to brownish black. Conidiophores were branched, brown. Conidia were brown, long ellipsoid, had 4-12 transverse and 0-3 longitudinal septa; measured within 67.5-127.8 (average = 105.6) × 12.5-27.8 (average = 20.4) µm (n = 30). Apical beak was longer than conidia body. measured within 40.5-423.5 (average = 365.2) × 2.5-5.8 (average = 3.2) µm (n = 30). Based on morphological characteristics, the three isolates were identified as Alternaria crassa (Sacc.) Rands (Simmons 2007). Molecular identification was performed using the colony polymerase chain reaction method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012) to amplify internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), RNA polymerase second largest subunit (RPB2) and translation elongation factor (TEF1) with primers of ITS1/ITS4, GDF1/GDR1, RPB2-5F2/fRPB2-7cR, and EF-1α-F/EF-1α-R, respectively (Walther et al. 2013; Woudenberg et al. 2015; Nishikawa and Nakashima. 2020). Amplicons of the isolates were sequenced and submitted to GenBank (ITS, ON430524-ON430526; GAPDH, ON500656-ON500658; RPB2, ON500659-ON500661; TEF1, ON500662-ON500664). The sequences were 100% identical with those of Alternaria crassa strain CBS 116647 upon BLAST analysis. The sequences were also concatenated for phylogenetic analysis by maximum likelihood. The isolates clustered with A. crassa (CBS 116647, CBS 116648, CBS CBS-110.38, and CBS_103.18 ). Thus, the fungus associated with leaf yellow spot on D. stramonium was identified as A. crassa. Pathogenicity tests were conducted in a greenhouse at 24 ℃-30 ℃ with 80% relative humidity using 3 isolates. Individual plants were grown in pots (n = 5, 1 month old). The unwounded leaflets were inoculated using three isolates (DSAC-1, DSAC-2, and DSAC-3). The fungal mycelium on 5 mm-diameter PDA plugs were placed faced down to the leaves. Sterile PDA was used for mock inoculated comtrols.. The test was performed three times. Disease symptoms were observed on the leaves after 7 days, whereas the controls remained healthy. The pathogen was re-isolated from infected leaves and was morphologically identical to the original isolates, fulfilling Koch's postulates. A. crassa was reported causing leaf spot on D. stramonium in Algeria (Nabahat et al. 2020). To our knowledge, this report is the first report of A. crassa causing leaf yellow spot on D. stramonium in China. This pathogen possesses potential biocontrol properties on the invasive weed, while this study also provides an important reference for the control of the disease of the medicinal plant.
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Claims 7
Claim · model-written summary
Yellow leaf spot incidence on Datura stramonium was 85% in the field.
- Taxon
- Datura stramonium
.jpg?width=60)
Datura stramoniume0 - Outcome
- disease incidencee1
- Value
- 85%e1
- Setting
- fielde1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant.”
e1“The disease incidence in the field was 85% (n = 50, about 1 ha).”
Claim · model-written summary
The three isolates associated with Datura leaf spot were identified as Alternaria crassa.
- Taxon
- Datura stramoniumDatura stramoniume0
- Interactor
- Alternaria crassaAlternaria crassae1pathogen
- Outcome
- identified as Alternaria crassae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant.”
e1“Based on morphological characteristics, the three isolates were identified as Alternaria crassa (Sacc.) Rands (Simmons 2007).”
Claim · model-written summary
Isolate sequences were 100% identical to Alternaria crassa strain CBS 116647.
- Taxon
- Datura stramoniumDatura stramoniume0
- Interactor
- Alternaria crassaAlternaria crassae1pathogen
- Outcome
- sequences were 100% identicale1
- Value
- 100%e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant.”
e1“The sequences were 100% identical with those of Alternaria crassa strain CBS 116647 upon BLAST analysis.”
Claim · model-written summary
The isolates clustered with reference A. crassa strains.
- Taxon
- Datura stramoniumDatura stramoniume0
- Interactor
- A. crassaAlternaria crassae1pathogen
- Outcome
- isolates clustered with A. crassae1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant.”
e1“The isolates clustered with A. crassa (CBS 116647, CBS 116648, CBS CBS-110.38, and CBS_103.18 ).”
Claim · model-written summary
Inoculated Datura leaves developed symptoms after seven days while controls remained healthy.
- Taxon
- Datura stramoniumDatura stramoniume0
- Treatment
- inoculated using three isolatese1
- Interactor
- three isolatese1pathogen
- Outcome
- Disease symptoms were observed on the leavese3
- Qualifier
- after 7 dayse3
- Comparator
- mock inoculated comtrolse2
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant.”
e1“The unwounded leaflets were inoculated using three isolates (DSAC-1, DSAC-2, and DSAC-3).”
e2“Sterile PDA was used for mock inoculated comtrols..”
e3“Disease symptoms were observed on the leaves after 7 days, whereas the controls remained healthy.”
Claim · model-written summary
The pathogen was re-isolated from infected Datura leaves and matched the original isolates.
- Taxon
- Datura stramoniumDatura stramoniume0
- Interactor
- pathogene1pathogen
- Outcome
- pathogen was re-isolated from infected leaves and was morphologically identicale1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Datura stramonium L.(jimson weed) is an invasive weed in agricultural fields and a medicinal plant.”
e1“The pathogen was re-isolated from infected leaves and was morphologically identical to the original isolates, fulfilling Koch's postulates.”
Claim · model-written summary
The authors report the first occurrence of A. crassa causing yellow leaf spot on Datura stramonium in China.
- Taxon
- D. stramoniumDatura stramoniume0
- Interactor
- A. crassaAlternaria crassae0pathogen
- Outcome
- first report of A. crassa causing leaf yellow spote0
- Setting
- Chinae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“To our knowledge, this report is the first report of A. crassa causing leaf yellow spot on D. stramonium in China.”
The same questions in other papers
inoculation · disease · Datura stramonium (jimsonweed)Results agree
3 papers in the same direction as this paper
- negative
- negative
- negative
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.