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journal1 ›› 2019, Vol. 35 ›› Issue (2): 240-246.DOI: 10.16409/j.cnki.2095-039x.2019.02.004

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Colonization Dynamics and Growth Promotion Effect of Marine Bacterium Strain SH-27 in Soybean and Its Biological Control Effect on Phytophthora Root Rot Disease

LIN Qiaoling1, LU Naihui2, HE Hong1, YUAN Yue1   

  1. 1. Agricultural College, Guangdong Ocean University, Zhanjiang 524088, China;
    2. Zhanjiang Customs, Zhanjiang 524022, China
  • Received:2018-07-20 Online:2019-04-08 Published:2019-04-12

Abstract: Marine bacterium strain SH-27 was applied to soybean plants to investigate the colonization dynamics, growth promotion effect and the biological control effect on Phytophthora root rot disease. Mutant strainSH-27Rif with stable marker of antibiotic rifampicin and inhibitory effect against Phytophthora sojae were screened by using the rifampin-resistant mutants and dual culture method. Colonizing dynamics of the strain SH-27Rif in root, stem and leaf of soybean were investigated by treating with root irrigating and leaf daubing. Then the effects of growth promotion and controlling disease on soybean seedlings were studied by pot tests. The results indicated that the resistance marker of the mutant strain SH-27Rif was remained stable after 10 generations of cultivation. The inhibition rates of strain SH-27Rif and original strain SH-27 against P. sojae were 56.92% and 57.58%, respectively. The strain SH-27Rif could colonize for 31 days or more in soybean seedlings by root irrigating and leaf daubing. After root irrigating, the colonization quantity of strain SH-27Rif trended to increase firstly and then decrease. The highest quantity in roots was 6.6×105 cfu/g at 21 d after inoculation. Bacteria quantities in different parts were root > stem > leaf. After leaf daubing, the highest colonization quantity in leave was 6.3×105 cfu/g at 1 d after inoculation and then decreased quickly. Bacteria quantities in different parts were leaf>stem and strain SH-27Rif wasn't detected in root. Pot tests demonstrated that the height, root length, stem diameter, fresh weight, dry weight, chlorophyll and root activity of soybean seedlings treated with SH-27 fermentation broth were significantly higher than those of the control groups. When challenging the pathogen Phytophthora sojae, soybean seedlings treated by SH-27 showed decreased disease index significantly and the control efficacies were 83.44%, 66.34%, 57.18% and 52.85% at 3 d, 5 d,7 d and 9 d, respectively. In conclusion, the results indicated that marine bacterium strain SH-27 was an excellent candidate for developing a biocontrol agent to control Phytophthora root rot of soybean.

Key words: marine bacteria, soybean Phytophthora root rot, colonization, Bacillus amylolique faciens

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