PMID- 33434032
OWN - NLM
STAT- Publisher
LR - 20240222
IS - 0191-2917 (Print)
IS - 0191-2917 (Linking)
DP - 2021 Jan 12
TI - First Report of Colletotrichum siamense Causing Leaf Spot on Alocasia macrorrhiza
in China.
LID - 10.1094/PDIS-11-20-2361-PDN [doi]
AB - Alocasia macrorrhiza (L.) Schott, known as Alocasia is found in the Araceae, and
is widely planted in southern China for its ornamental and medicinal value. This
plant has a wide range of pharmacological effects, and has potential anti-tumor
activity (Lei et al. 2013). In July of 2019, leaf spots were observed on A.
macrorrhiza in the Xixiangtang Area, Nanning, Guangxi, China. Disease symptoms
began with water-soaked yellow-green spots and progressed to form brown, round or
oval lesions with yellow halos. Under severe conditions, spots merged into larger
irregular lesions. More than 60% of the plants in a 0.5 ha field showed disease
symptoms. Symptomatic leaves were collected and cut into small pieces (3x3 mm).
Leaf pieces from the margin of the necrotic tissue were surface sterilized in 75%
alcohol for 10 s, followed by 2% sodium hypochlorite solution for 2 min, then
rinsed three times in sterile distilled water. Tissues were plated on potato
dextrose agar (PDA) and incubated at 28 degrees C for 5 days in the dark. Among over 30
isolates, most shared a similar morphology, the isolation rate of these was 86.7%
and three of these (GY1-1A, GY1-1B, and GY1-1C) were chosen for single-spore
purification and used for fungal morphological characterization and
identification. White feathery aerial mycelia with olivaceous gray mycelia below
were observed in 7-day cultures. After 14 days, orange conidia were observed.
Conidia were hyaline, guttulate, smooth, one-celled, and cylindrical, averaged
13.79 mum x 5.26 mum, 13.89 mum x 5.33 mum and 13.92 mum x 5.42 mum for GY1-1A, GY1-1B
and GY1-1C, respectively. Appressoria were mostly irregular in outline, deeply
lobed or lightly lobed, gray brown to dark brown, conidial appressoria were 7.93
to 8.74 mum x 5.26 to 5.42 mum, mycelial appressoria were 7.15 to 10.11 mum x 5.60
to 7.44 mum. These morphological characteristics were similar to the C. siamense
as previously described (Weir et al. 2012). The partial internal transcribed
spacer (ITS) regions, actin (ACT), chitin synthase (CHS-1),
glyceraldehydes-3-phosphate dehydrogenase (GAPDH), calmodulin (CAL), beta-tubulin
(TUB2), and the intergenic region of apn2 and MAT1-2-1 (ApMAT) were amplified
from genomic DNA for the three isolates using primers ITS4/ITS1 (White et al.
1990), ACT-512F/ACT-783R, CHS-79F/CHS-354R, GDF1/GDR1, CL1C/CL2C, Bt2a/Bt2b (Weir
et al. 2012), and AM-F/AM-R (Silva et al. 2012) and sequenced. All sequences
showed over 99% identity with C. siamense and were deposited in GenBank (ITS,
MW040179-MW040181; ACT, MW049220-MW049222; CHS-1, MW049229-MW049231; GAPDH,
MW049232-MW049234; CAL, MW049226-MW049228; TUB, MW049235-MW049237; ApMAT,
MW049223-MW049225). Maximum Likelihood (ML) phylogenetic tree was constructed
with MEGA 5 using the concatenation of multiple sequences (ACT, CHS-1, GAPDH,
ITS, TUB2, CAL). According to the phylogenetic tree, all three isolates were
found with C. siamense with 95% bootstrap support. To confirm pathogenicity,
three sets (three plants per set) of healthy leaves were slightly scratched with
autoclaved toothpicks at each of eight locations. Each inoculation location was a
cross (2 mm length) and inoculation location was at least 3 cm apart. Ten mul of
conidial suspension (106 conidia /ml in 0.1% sterile Tween 20) was applied to the
inoculation areas. A control group was mock inoculated with 0.1% sterile Tween
20. Plants were covered with plastic bags to maintain a high humidity environment
and placed in a 28 degrees C growth chamber with constant light for 7 days. Inoculated
leaves showed yellowish brown spots (0.4 x 0.65 cm), but no symptoms were
observed in the control group. The fungus was reisolated from inoculated leaves,
and these isolates matched the molecular and morphological characteristics of the
original isolates confirming Koch's postulates. Reported hosts of this pathogen
include Coffea arabica, Carica papaya, Melilotus indicus and Litchi chinensis
(Weir et al. 2012; Qin et al. 2017; Ling et al. 2019) and so on. To our
knowledge, this is the first report of C. siamense causing leaf spot on A.
macrorrhiza in China. The identification of this pathogen provides a foundation
for the management of leaf spot on this medicinal plant.
FAU - Huang, Rong
AU - Huang R
AD - Yangtze University, 47897, College of Life Sciences, Jingzhou County Jingmi Road,
Jingzhou, Hubei , China, 434025; 1930745671@qq.com.
FAU - Sun, Wenxiu
AU - Sun W
AD - Yangtze University, 47897, College of life Sciences, Jingzhou, Hubei , China;
75102310@qq.com.
FAU - Li, Wei
AU - Li W
AD - Yangtze University, 47897, College of life sciences, Jingzhou, Hubei , China;
496233825@qq.com.
FAU - Zhou, Chunxiang
AU - Zhou C
AD - Institute of Plant Protection, Guangxi Academy of Agricultural Science and
Guangxi Key Laboratory of Biology for Crop Diseases and Insect Pests, Nanning,
Guangxi, Nanning, Guangxi, China; 875919451@qq.com.
FAU - Huang, SuiPing
AU - Huang S
AD - Guangxi University, College of Agriculture, 100 daxue road, Nanning, Guangxi
Province, Nanning, China, 530004; 361566787@qq.com.
FAU - Tang, Lihua
AU - Tang L
AD - Guangxi Academy of Agricultural Sciences, Institute of plant protection, 174,
daxuedong road, nanning, Guangxi, Nanning, Guangxi, China, X2ogGBuM.
AD - Guangxi Key Laboratory of Biology for Crop Diseases and Insect Pests, Nanning,
Guangxi, China; 654123597@qq.com.
FAU - Li, Qili
AU - Li Q
AD - Guangxi Academy of Agricultural Sciences, Institute of plant protection, 174
daxue road, Nanning, Guangxi Province, Nanning, Guangxi, China, 530007;
65615384@qq.com.
FAU - Guo, Tangxun
AU - Guo T
AD - Guangxi Academy of Agricultural Sciences, Institute of plant protection, Nanning,
Guangxi, China; guotangxun@gxaas.net.
FAU - Mo, Jianyou
AU - Mo J
AD - Guangxi Academy of Agricultural Sciences, Institute of plant protection, Nanning,
Guangxi, China; mojianyou@gxaas.net.
FAU - Ning, Ping
AU - Ning P
AD - Guangxi Agricultural Vocation-Technical College, Department of Biotechnology,
Nanning, Guangxi, China; 382279601@qq.com.
LA - eng
PT - Journal Article
DEP - 20210112
PL - United States
TA - Plant Dis
JT - Plant disease
JID - 9882809
SB - IM
OTO - NOTNLM
OT - Alocasia macrorrhiza
OT - Colletotrichum siamense
OT - Leaf Spot
EDAT- 2021/01/13 06:00
MHDA- 2021/01/13 06:00
CRDT- 2021/01/12 17:18
PHST- 2021/01/12 17:18 [entrez]
PHST- 2021/01/13 06:00 [pubmed]
PHST- 2021/01/13 06:00 [medline]
AID - 10.1094/PDIS-11-20-2361-PDN [doi]
PST - aheadofprint
SO - Plant Dis. 2021 Jan 12. doi: 10.1094/PDIS-11-20-2361-PDN.