Influence of Commercial Antibiotics on Biocontrol of Soft Rot and Plant Growth Promotion in Chinese Cabbages by Bacillus vallismortis EXTN-1 and BS07M

Abstract

We investigated influence of three commercial antibiotics viz., oxolinic acid, streptomycin, and validamycin A, on biocontrol and plant growth promoting activities of Bacillus vallismortis EXTN-1 and BS07M in Chinese cabbage. Plants were pre-drenched with these strains followed by antibiotics application at recommended and ten-fold diluted concentration to test the effect on biocontrol ability against soft rot caused by Pectobacterium carotovorum SCC1. The viability of the two biocontrol strains and bacterial pathogen SCC1 was significantly reduced by oxolinic acid and streptomycin in vitro assay, but not by validamycin A. In plant trials, strains EXTN-1 and BS07M controlled soft rot in Chinese cabbage, and there was a significant difference in disease severity when the antibiotics were applied to the plants drenched with the two biocontrol agents. Additional foliar applications of oxolinic acid and streptomycin reduced the disease irrespective of pre-drench treatment of the PGPRs. However, when the plants were pre-drenched with EXTN-1 followed by spray of validamycin A at recommended concentration, soft rot significantly reduced compared to untreated control. Similarly, strains EXTN-1 and BS07M significantly enhanced plant growth, but it did not show synergistic effect with additional spray of antibiotics. Populations of the EXTN-1 or BS07M in the rhizosphere of plants sprayed with antibiotics were significantly affected as compared to control. Taken together, our results suggest that the three antibiotics used for soft rot control in Chinese cabbage could affect bacterial mediated biocontrol and plant growth promoting activities. Therefore, combined treatment of the PGPRs and the commercial antibiotics should be carefully applied to sustain environmental friendly disease management.

Enhanced Tolerance of Chinese Cabbage Seedlings Mediated by Bacillus aryabhattai H26-2 and B. siamensis H30-3 against High Temperature Stress and Fungal Infections

“…plantarum GR53 treatment ( Kang et al, 2015 ). Suppressed bacterial soft rot of Chinese cabbage was mediated by B. toyonensis CAB12243-2 and B. vallismortis BS07M ( Kim et al, 2018 ; Sang et al, 2015 ). Fungi Alternaria brassicicola and Colletotrichum higginsianum caused black spot and anthracnose diseases on Chinese cabbage plants, respectively.…”

Induced Tolerance to Salinity Stress by Halotolerant Bacteria Bacillus aryabhattai H19-1 and B. mesonae H20-5 in Tomato Plants

“…Therefore, PGPB can be one of the possible strategies for alleviating damage by salinity stress. Bacillus vallismortis BS07M was also reported to promote plant growth and reduce soft rot in Chinese cabbages [23]; therefore, in this study, strain BS07M was used as a plant growth-promoting bacterium.…”

Antibiotic Resistance of Pectobacterium Korean Strains Susceptible to the Bacteriophage phiPccP-1

“…P. carotovorum also showed the susceptibility to filter paper disks dipped in 200 ppm of streptomycin (Gokul et al, 2019). Foliar application of streptomycin products like Agreptor (GyungNong, Seoul, Korea), Buramycin (Farm Hannong, Seoul, Korea), and Agrimycin (SUNGBO Chemicals, Seoul, Korea) has been used to control the soft rot disease caused by P. carotovorum (Bhat et al, 2017;Sang et al, 2015) and P. odoriferum (Lee et al, 2021). The manufacturer-recommended concentration of representative streptomycin products to control the soft rot disease in Korea are 250 μg/ml for Agreptor and Buramycin and 75 μg/ml for Agrimycin (Abd-El-Khair and Karima, 2007;Shrestha et al, 2009).…”