PMID- 38240656
OWN - NLM
STAT- Publisher
LR  - 20240119
IS  - 0191-2917 (Print)
IS  - 0191-2917 (Linking)
DP  - 2024 Jan 19
TI  - First Report of Alternaria Leaf Spot Caused by Alternaria alternata on Ulmus 
      parvifolia in Jiangsu, China.
LID - 10.1094/PDIS-10-23-2038-PDN [doi]
AB  - Ulmus parvifolia Jacq. is an important tree with ornamental value, which is 
      widely planted in Hebei and southern regions of China. In September 2022, a leaf 
      spot symptom was observed on about approximately 20% U. parvifolia seedlings 
      growing a tree farm (20000 m2) of Jiangsu Academy of Forestry (118 degrees 45'57.30''E, 
      31 degrees 51'27. 94''N). Gray to black spots appeared on leaves of seedlings. Five 
      diseased leaves were collected from five different seedlings. The pieces were 
      excised from the margins between healthy and diseased tissues, surface sterilized 
      in 75% ethanol for 30 s and then in 1.5% NaClO for 90 s, rinsed three times in 
      sterilized distilled water, plated on potato dextrose agar (PDA) and incubated at 
      25℃ in the darkness. Pure cultures were obtained by monosporic isolation. Six 
      isolates with identical morphological features and the internal transcribed 
      spacer (ITS) sequences were obtained (the isolate rate of 67%), and identified as 
      Alternaria sp. A representative isolate, LY-1-1 was used for the further study. 
      The colony of LY-1-1, growing on PDA was cotton-like and brown in color with 
      gray-white aerial hyphae on their surfaces, and its reverse was dark grey. The 
      conidia were ovate to pear-shaped, brown in color, with 1 to 4 transverse septa 
      and 0 to 1 longitudinal septa, parietal cells extending into the beak, and 
      measured 7.1 to 12.5x3.8 to 7.1 microm (n=35). These characteristics were consistent 
      with the description of Alternaria sp. (Simmons 2007). The regions of ITS, large 
      subunit ribosomal RNA (LSU), small subunit ribosomal RNA (SSU), anonymous region 
      OPA10-2 genomic sequence (OPA10-2), Alternaria 1 major allergen (Alta1), 
      glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and translation elongation 
      factor 1-alpha (TEF1) genes (GenBank Accession No. OR047916, OR051904, OR047919, 
      OR061065, OR061063, OR061064, and OR061062, respectively) were amplified (White 
      et al. 1990; Woudenberg et al. 2015) and sequenced. These obtained sequences 
      showed 99.86-100% similarity to the ITS (514/515 bp) of A. alternata isolate 
      SPM-2 (OR378581), LSU (801/801 bp) of isolate B9 (OR366492), SSU (1019/1020 bp) 
      of strain LSU0766 (MT000349), OPA10-2 (632/633 bp) of strain 19-1 (MN185000), 
      Alta1 (470/470 bp) of strain CMML21-73 (OQ831518), GAPDH (177/177 bp) of isolate 
      CS36-3 (KY814638), and TEF1 (240/240 bp) of isolate SY-6 (OP980553). A 
      neighbor-joining phylogenetic tree was generated by combining all sequenced loci 
      in MEGA7. The isolate LY-1-1 clustered in the A. alternata clade with 98% 
      bootstrap support. Three 3-month-old U. parvifolia seedlings were wounded with a 
      sterile needle and inoculated with 20 muL conidia suspension (1x106 spores/mL) on 
      the left sides of leaves. Inoculation on the right side with 20 microL of sterile 
      water was treated as a control. All inoculated plants were incubated in a 
      greenhouse at 25℃, 80% relative humidity, and a 12-h light/dark cycle. The 
      experiment was repeated three times. After 5 days of inoculation, typical gray to 
      black spots were found on the left sides of all inoculated leaves, and the 
      control did not have any leaf spot symptoms. Subsequently, the same fungus was 
      reisolated and identified based on morphological and molecular traits, fulfilling 
      Koch's postulates. The A. alternata has been reported to cause leaf spot on pecan 
      (Wu et al. 2020), fruit spot on olive (Alam et al. 2019) and fruit rot on lychee 
      (Alam et al. 2017). However, there are no other reports of A. alternata on U. 
      parvifolia in the world. Thus, this study provides an important reference for the 
      biology, epidemiology of A. alternata.
FAU - Lyu, Yunzhou
AU  - Lyu Y
AD  - Jiangsu Academy of Forestry, 499751, Ningdan Road 109, Nanjing, China, 211153; 
      yunzhoulv@163.com.
FAU - Dong, Xiaoyun
AU  - Dong X
AD  - Jiangsu Academy of Forestry, 499751, Nanjing, China; 527971773@qq.com.
FAU - Sun, Hainan
AU  - Sun H
AD  - Jiangsu Academy of Forestry, 499751, Nanjing, China; sunhainan1989@hotmail.com.
FAU - Li, Ru
AU  - Li R
AD  - Jiangsu Academy of Forestry, 499751, Nanjing, China; 641054713@qq.com.
FAU - Li, Shan
AU  - Li S
AD  - Jiangsu Academy of Forestry, 499751, Nanjing, China; 641975669@qq.com.
FAU - Hu, Longjiao
AU  - Hu L
AD  - No. 1, qianhuhou village, Xuanwu DistrictNanjing, Jiangsu, China, 210014; 
      longjiaohu812@163.com.
FAU - Huang, Li-Bin
AU  - Huang LB
AD  - Jiangsu Academy of Forestry, 499751, Nanjing, China; lky209210@outlook.com.
LA  - eng
PT  - Journal Article
DEP - 20240119
PL  - United States
TA  - Plant Dis
JT  - Plant disease
JID - 9882809
SB  - IM
OTO - NOTNLM
OT  - Alternaria alternata
OT  - Ulmus parvifolia
OT  - leaf spot
EDAT- 2024/01/19 12:43
MHDA- 2024/01/19 12:43
CRDT- 2024/01/19 09:53
PHST- 2024/01/19 12:43 [medline]
PHST- 2024/01/19 12:43 [pubmed]
PHST- 2024/01/19 09:53 [entrez]
AID - 10.1094/PDIS-10-23-2038-PDN [doi]
PST - aheadofprint
SO  - Plant Dis. 2024 Jan 19. doi: 10.1094/PDIS-10-23-2038-PDN.