Pseudomonas oleovorans strain KBPF-004 culture supernatants reduced seed transmission of Cucumber....virus, and remodeled aggregation of 126 kDa and subcellular localization of movement protein of pepper mild mottle virus

Authors: KIM, NAM-GYU - Central Research Institute - Korea; SEO, EUN-YOUNG - Chungnam National University; HAN, SANG-HYUK - Chungnam National University; GONG, JUN-SU - Chungnam National University; Domier, Leslie; Hammond, John; JANG, CHEOL - Central Research Institute - Korea; LIM, HYOUN-SUB - Chungnam National University

Submitted to: Plant Pathology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2017
Publication Date: 8/1/2017
Citation: Kim, N., Seo, E., Han, S., Gong, J., Domier, L.L., Hammond, J., Jang, C., Lim, H. 2017. Pseudomonas oleovorans strain KBPF-004 culture supernatants reduced seed transmission of Cucumber green mottle mosaic virus and Pepper mild mottle virus, and remodeled aggregation of 126 kDa and subcellular localization of movement protein of Pepper mild mottle virus. Plant Pathology Journal. 33(4):393-401. https://doi.org/10.5423/PPJ.OA.03.2017.0047.
DOI: https://doi.org/10.5423/PPJ.OA.03.2017.0047

Interpretive Summary: Viral diseases of plants cause significant economic losses in a wide variety of crops; seed-borne transmission introduces disease early in the crop cycle, facilitating secondary spread by other means during the growing season and resulting in greater crop loss. Physical or chemical treatments to reduce levels of seed-borne transmission are effective in some cases, but may adversely affect seed viability and longevity. Scientists in Korea and the U.S. identified an extract from a particular strain of soil-inhabiting bacterium in Korea that could be effective in reducing viral transmission in plants. The extract reduced viral infectivity and seed transmission of two economically important viruses affecting peppers or cucurbit crops. This work could ultimately benefit seed producers and farmers by providing alternative methods for reducing seed transmission of plant viruses.

Technical Abstract: Efforts to control viral diseases in crop production include several types of physical or chemical treatments; antiviral extracts from a number of plants have also been examined to inhibit plant viral infection. However, treatments utilizing naturally selected microorganisms with activity against plant viruses are poorly documented. Here we report the effects of an extract from a soil inhabiting bacterium isolated in Korea, Pseudomonas oleovorans strain KBPF-004 (developmental code KNF2016) which showed antiviral activity against mechanical transmission of tobamoviruses. Antiviral activity was also evaluated in seed transmission of two tobamoviruses, Pepper mild mottle virus and Cucumber green mottle mosaic virus, by treatment of seed collected from infected pepper and watermelon, respectively. Pepper and watermelon seeds were treated with culture supernatant of P. oleovorans strain KBPF-004 or control strain ATCC 8062 before planting. Seeds germinated after treatment with water or ATCC 8062 yielded about 60% CGMMV or PMMoV positive plants, whereas <20% of KBPF-004-treated seeds were virus-infected, a significantly reduced seed transmission rate. Furthermore, supernatant of P. oleovorans strain KBPF-004 remodeled aggregation of the 126 kDa PMMoV protein and subcellular localization of a movement protein in Nicotiana benthamiana, diminishing aggregation of the 126 kDa protein and essentially abolishing association of the movement protein with the microtubule network. In leaves agroinfiltrated with constructs expressing the coat protein (CP) of either PMMoV or CGMMV, less full-size CP was detected in the presence of supernatant of P. oleovorans strain KBPF-004. These changes may contribute to the antiviral effects of P. oleovorans strain KBPF-004.