title: Selection and differentiation of Bacillus spp. Antagonistic to Fusarium oxysporum f.sp. lycopersici and Alternaria solani infecting Tomato.
abstract: Antagonistic Bacillus spp. displaying in vitro production of siderophore, chitinase, and β-1,3-glucanase were identified from dual culture assays. In independent greenhouse studies, seed bacterization and soil application of Bacillus atrophaeus S2BC-2 challenge inoculated with Fusarium oxysporum f.sp. lycopersici (FOL) and Alternaria solani (AS) recorded low percent disease index of 25.3 and 28.7, respectively, over nonbacterised pathogen control (44.3 and 56.4). The low disease incidence corroborated with tomato growth promotion with high vigor index (8,041.2) and fresh plant weight (82.5 g) on challenge inoculation with FOL. Analysis of root and leaf samples in rhizobacterial treatment challenged with FOL and AS revealed maximum induction of chitinase (1.9 and 1.7 U/mg of protein, respectively) and β-1,3-glucanase (23.5 and 19.2 U/mg of protein, respectively). In native gel activity assays, the rhizobacterial treatment on challenge inoculation strongly expressed three high intensity PO isoforms along with one low intensity isoform. In studies on genetic diversity of the Bacillus strains by repetitive extragenomic palindromic-polymerase chain reaction (REP-PCR) and amplified rDNA restriction analysis (ARDRA) patterns, ARDRA was more highly discriminant than REP-PCR and allowed grouping of the strains and differentiation of the antagonistic strains from other isolates.
authors.affiliation: Floriculture Pathology Laboratory, Institute of Himalayan Bioresource Technology, Council of Scientific and Industrial Research, Palampur, 176 061, Himachal Pradesh, India. shanpatho@yahoo.com
authors.forename: Veerubommu
authors.initials: V
authors.lastname: Shanmugam
authors.forename: Kamini
authors.initials: K
authors.lastname: Atri
authors.forename: Samriti
authors.initials: S
authors.lastname: Gupta
authors.forename: Nandina
authors.initials: N
authors.lastname: Kanoujia
authors.forename: Digvijay Singh
authors.initials: DS
authors.lastname: Naruka
mesh_terms: D000528:Alternaria / Q000254:growth & development* / Q000472:pathogenicity; D000898:Antibiosis; D001407:Bacillus / Q000145:classification / Q000302:isolation & purification* / Q000378:metabolism / Q000502:physiology*; D018533:Biomass; D002688:Chitinases / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D005670:Fusarium / Q000254:growth & development* / Q000472:pathogenicity; D043326:Glucan 1,3-beta-Glucosidase / Q000378:metabolism; D018551:Solanum lycopersicum / Q000254:growth & development / Q000382:microbiology*; D058889:Molecular Typing; D010572:Pest Control, Biological / Q000379:methods; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D017262:Siderophores / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D017262:Siderophores; D002688:Chitinases; D043326:Glucan 1,3-beta-Glucosidase; C117648:beta-1,3-exoglucanase