title: Characterization of Bacillus isolates of potato rhizosphere from andean soils of Peru and their potential PGPR characteristics.
abstract: Bacillus spp. are well known rhizosphere residents of many crops and usually show plant growth promoting (PGP) activities that include biocontrol capacity against some phytopatogenic fungi. Potato crops in the Andean Highlands of Peru face many nutritional and phytophatogenic problems that have a significant impact on production. In this context is important to investigate the natural presence of these microorganisms in the potato rhizosphere and propose a selective screening to find promising PGP strains. In this study, sixty three Bacillus strains isolated from the rhizosphere of native potato varieties growing in the Andean highlands of Peru were screened for in vitro antagonism against Rhizoctonia solani and Fusarium solani. A high prevalence (68%) of antagonists against R. solani was found. Ninety one percent of those strains also inhibited the growth of F. solani. The antagonistic strains were also tested for other plant growth promotion activities. Eighty one percent produced some level of the auxin indole-3-acetic acid, and 58% solubilized tricalcium phosphate. Phylogenetic analysis revealed that the majority of the strains belonged to the B. amyloliquefaciens species, while strains Bac17M11, Bac20M1 and Bac20M2 may correspond to a putative new Bacillus species. The results suggested that the rhizosphere of native potatoes growing in their natural habitat in the Andes is a rich source of Bacillus fungal antagonists, which have a potential to be used in the future as PGP inoculants to improve potato crop.
authors.affiliation: Laboratorio de Ecología Microbiana y Biotecnología  "Marino Tabusso", Departamento de Biología, Facultad de Ciencias, Universidad Nacional Agraria La Molina , Av. La Molina s/n, Lima , Peru.
authors.forename: Pamela
authors.initials: P
authors.lastname: Calvo
authors.forename: Ernesto
authors.initials: E
authors.lastname: Ormeño-Orrillo
authors.forename: Esperanza
authors.initials: E
authors.lastname: Martínez-Romero
authors.forename: Doris
authors.initials: D
authors.lastname: Zúñiga
keywords: 16S rRNA gene.; Bacillus; antagonism; phosphate solubilization; plant growth-promoting rhizobacteria; potato
references.citation: Plant Physiol. 1951 Jan;26(1):192-5
references.pmid: 16654351
references.citation: Appl Environ Microbiol. 1996 Nov;62(11):4081-5
references.pmid: 16535440
references.citation: J Bacteriol. 1991 Jan;173(2):697-703
references.pmid: 1987160
references.citation: FEMS Microbiol Ecol. 2005 Jan 1;51(2):215-29
references.pmid: 16329870
references.citation: Microbiology (Reading). 2002 Jul;148(Pt 7):2097-2109
references.pmid: 12101298
references.citation: Appl Environ Microbiol. 1995 Feb;61(2):793-6
references.pmid: 16534942
references.citation: FEMS Microbiol Lett. 1999 Jan 1;170(1):265-70
references.pmid: 9919677
references.citation: Phytopathology. 2004 Nov;94(11):1267-71
references.pmid: 18944465
references.citation: Indian J Microbiol. 2008 Jun;48(2):267-73
references.pmid: 23100719
references.citation: Microb Ecol. 2007 Aug;54(2):341-51
references.pmid: 17492474
references.citation: Mol Plant Microbe Interact. 2007 Jun;20(6):619-26
references.pmid: 17555270
references.citation: Mol Biol Evol. 2007 Aug;24(8):1596-9
references.pmid: 17488738
references.citation: Int J Syst Evol Microbiol. 2007 Aug;57(Pt 8):1846-1850
references.pmid: 17684269
references.citation: Appl Environ Microbiol. 2005 Sep;71(9):4951-9
references.pmid: 16151072
references.citation: FEMS Microbiol Ecol. 2004 May 1;48(2):249-59
references.pmid: 19712408