Welcome to Chinese Journal of Tropical Crops,

Chinese Journal of Tropical Crops ›› 2021, Vol. 42 ›› Issue (4): 1086-1091.DOI: 10.3969/j.issn.1000-2561.2021.04.026

• Plant Protection & Bio-safety • Previous Articles     Next Articles

Identification of the Pathogen of Stenotaphrum helferi Leaf Spot

ZHENG Jinlong1, LIU Wenbo2,*(), HE Chunping1, YI Kexian1,*(), XI Jingen1, LIANG Yanqiong1, Gbokie Jr Thomas3, WU Yang4   

  1. 1. Environment and Plant Protection Institute, Chinese Academy of Tropical Agricultural Sciences / Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture and Rural Affairs, Haikou, Hainan 571101, China
    2. College of Plant Protection, Hainan University, Haikou, Hainan 570228, China
    3. College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
    4. School of Life Sciences, Jinggangshan University, Ji’an, Jiangxi 343009, China
  • Received:2020-03-28 Revised:2020-06-24 Online:2021-04-25 Published:2021-04-25
  • Contact: LIU Wenbo,YI Kexian

Abstract:

This study aimed to identify the pathogen of the leaf spot of Stenotaphrum helferi. A total of 61 leaf samples of S. helferi with suspected leaf spot disease were collected from six provinces in China (Hainan, Guangdong, Guangxi, Yunnan, Fujian and Jiangsu), the United States and the South Africa. The potential causal agents were isolated and 120 bacterial strains were obtained. The strains were identified in morphology, and by conducting pathogenicity assay in the accesions from Hainan. In addition, the strains were identified by the PCR method based on the rDNA internal transcribed spacer region (rDNA-ITS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and β-tubulin (TUB2) sequences. The analysis followed Koch's law and showed 40 strains with no pathogenisis, 70 strains with weak pathogenisis, and 10 strains with strong pathogenisis. The strains of No.55 with strong pathogenisis were selected for morphological observation, and the pathogens of the disease were preliminarily determined. Sequence identities of rDNA-ITS, GAPDH and TUB2 between No.55 strains and Curvularia lunata reached 99%, suggesting that the pathogenic bacteria of the leaf spot in S. helferi was C. lunata. Our findings would provide data to support future studies on the epidemiology, resistance mechanism and control strategy of the leaf spot disease of bluestocked grass.

Key words: Stenotaphrum helferi, leaf spot, Curvularia lunata, pathogen identification, pathogenicity assay

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