title: Biological Control of Bacterial Fruit Blotch of Watermelon Pathogen (Acidovorax citrulli) with Rhizosphere Associated Bacteria.
abstract: Bacterial fruit blotch (BFB), which is caused byAcidovorax citrulli, is a serious threat to watermelon growers around the world. The present study was conducted to screen effective rhizobacterial isolates against 35 differentA. citrulliisolates and determine their efficacy on BFB and growth parameters of watermelon. Two rhizobacterial isolates viz.Paenibacillus polymyxa(SN-22),Sinomonas atrocyanea(NSB-27) showed high inhibitory activity in the preliminary screening and were further evaluated for their effect on BFB and growth parameters of three different watermelon varieties under greenhouse conditions. The greenhouse experiment result revealed that SN-22 and NSB-27 significantly reduced BFB and had significant stimulatory effect on total chlorophyll content, plant height, total fresh weight and total dry weight compared to uninoculated plants across the tested three watermelon varieties. Analysis of the 16S ribosomal RNA (rRNA) sequences revealed that strains SN-22 belong toP. polymyxaand NSB-27 toS. atrocyaneawith the bootstrap value of 99% and 98%, respectively. The isolates SN-22 and NSB-27 were tested for antagonistic and PGP traits. The result showed that the tested isolates produced siderophore, hydrolytic enzymes (protease and cellulose), chitinase, starch hydrolytic enzymes and they showed phosphate as well as zinc solubilizing capacity. This is the first report ofP. polymyxa(SN-22) andS. atrocyanea(NSB-27) as biocontrol-plant growth promoting rhizobacteria on watermelon.
authors.affiliation: Division of Biological Resources Sciences, Kangwon National University, Chuncheon 24341, Korea.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Adhikari
authors.affiliation: Division of Biological Resources Sciences, Kangwon National University, Chuncheon 24341, Korea.
authors.forename: Dil Raj
authors.initials: DR
authors.lastname: Yadav
authors.affiliation: Division of Biological Resources Sciences, Kangwon National University, Chuncheon 24341, Korea.
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Kim
authors.affiliation: Division of Biological Resources Sciences, Kangwon National University, Chuncheon 24341, Korea.
authors.forename: Young Hyun
authors.initials: YH
authors.lastname: Um
authors.affiliation: Division of Biological Resources Sciences, Kangwon National University, Chuncheon 24341, Korea.
authors.forename: Hyun Seung
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Protected Horticulture Research Station, National Institute of Horticultural and Herbal Science, Rural Development Administration, Haman 52054, Korea.
authors.forename: Seong Chan
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Department of Applied Biology, Chungnam National University, Daejeon 34134, Korea.
authors.forename: Jeong Young
authors.initials: JY
authors.lastname: Song
authors.affiliation: Department of Applied Biology, Chungnam National University, Daejeon 34134, Korea.
authors.forename: Hong Gi
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Division of Biological Resources Sciences, Kangwon National University, Chuncheon 24341, Korea.
authors.forename: Youn Su
authors.initials: YS
authors.lastname: Lee
keywords: Acidovorax citrulli; biocontrol; plant growth promoting rhizobacteria; rhizosphere; watermelon