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Relationship Between Ralstonia solanacearum Diversity and Severity of Bacterial Wilt Disease in Tomato Fields in China
Author(s) -
Zheng Xuefang,
Zhu Yujing,
Liu Bo,
Zhou You,
Che Jianmei,
Lin Naiquan
Publication year - 2014
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/jph.12234
Subject(s) - ralstonia solanacearum , bacterial wilt , biology , virulence , pathogen , wilt disease , inoculation , population , veterinary medicine , microbiology and biotechnology , horticulture , medicine , sociology , biochemistry , demography , gene
A field survey was conducted to determine the relationship between R alstonia solanacearum diversity and severity of bacterial wilt disease in tomato plants grown in plastic greenhouses. Both vegetative and reproductive stages of the plants were surveyed, and the symptoms were empirically categorized into five scales: 0 (asymptomatic): 1st, 2nd, 3rd and 4th. The bacterial wilt pathogen was isolated from infected plants at each disease scale; pathogenic characteristics and population densities of the bacterial strains were assessed. Two hundred and eighty‐two isolates were identified as R . solanacearum , which were divided into three pathogenic types, virulent, avirulent and interim, using the attenuation index ( AI ) method and a plant inoculation bioassay. R alstonia solanacearum was detected in all asymptomatic and symptomatic tomato plants, with population numbers, ranging from 10.5 to 86.7 × 105 cfu/g. However, asymptomatic plants harboured only avirulent or interim R. solanacearum , whereas tomato plants displaying 1st or 2nd disease degree contained interim and virulent strains. Additionally, 3rd and 4th degree plants harboured only virulent strains. The disease was more severe in vegetative‐stage plants (disease severity index ( DSI ) 0.20) with higher total numbers of interim and virulent R . solanacearum strains than those in reproductive‐stage plants ( DSI 0.12). Three pathotypes of R . solanacearum coexisted in a competitive growth system in the tomato field, and their distribution closely correlated with the severity of tomato bacterial wilt.