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journal1 ›› 2019, Vol. 35 ›› Issue (1): 75-80.DOI: 10.16409/j.cnki.2095-039x.2019.01.015

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Competitive Growth of Ralstonial solanacearum Avirulent Strain FJAT-1458 and Virulent Strain FJAT-91

ZHENG Xuefang, LIU Bo, ZHU Yujing, ZHANG Haifeng, CHEN Deju, CHEN Yanping   

  1. Agricultural Bio-Resources Research Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350003, China
  • Received:2018-06-08 Online:2019-02-08 Published:2019-01-31

Abstract: The aim of this study is to determine the biocontrol competition mechanism of Ralstonia solanacearum avirulent strain FJAT-1458. Effects of carbon source, nitrogen source and culture time on the competitive growth between avirulent strain FJAT-1458 and virulent strain FJAT-91 were analyzed by co-culture in vitro. Furthermore, the competitive growth between FJAT-1458 and FJAT-91 was also in the tomato plant. The results showed that the virulent strain FJAT-91 could grow but the avirulent strain FJAT-1458 could not, when they were co-cultured in the media with content of carbon source less than 20%. Both strains could not reproduce when there was no nitrogen source. The cell concentration of FJAT-1458 (2.16×109 cfu/mL) was significantly less than FJAT-91 (3.24×109 cfu/mL) when the contents of carbon source and nitrogen source content were 100%. The growth of avirulent strain FJAT-1458 was faster than the virulent strain FJAT-91 before 24 h, but became slower after 24 h. The colonization number of FJAT-1458 and FJAT-91 reached the highest 5 d after sole inoculation or co-inoculation, and then quickly decreased. Moreover, the colonization number of FJAT-91 was 0 15 d after sole inoculation. The colonization number of both FJAT-1458 and FJAT-91 by sole inoculation was higher than that by co-inoculation (except for 15 d). The pre-inoculation of FJAT-1458 for 3 d had higher control efficiency (100%) than co-inoculation of FJAT-1458 and FJAT-91 at the same time (74.67%). It was concluded that the utilization abilities of carbon and nitrogen source for FJAT-1458 were poorer than those for FJAT-91 when co-cultured in vitro, but FJAT-1458 could restrained by the growth of FJAT-91 when co-inoculation in tomato plants. In the biocontrol competition mechanism of strain FJAT-1458, site competition may be the dominant factor, but not nutrient competition.

Key words: bacterial wilt disease, avirulent strain, Ralstonia solanacearum, competitive growth

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