03149naa a2200337 a 450000100080000000500110000800800410001902200140006002400420007410000190011624501740013526000090030950003360031852017520065465000230240665000200242965000280244965300290247765300160250665300170252265300300253970000140256970000140258370000120259770000150260970000150262470000180263970000150265770000140267277301250268610128172020-02-05       2009    bl uuuu     u00u1 u    #d  a1049-96447 a10.1016/j.biocontrol.2009.05.0062DOI1 aQUAGLIOTTO, L.  aThree native Pseudomonas fluorescens strains tested under growth chamber and field conditions as biocontrol agents against damping-off in alfalfa.h[electronic resource]  c2009  aArticle history: Received 1 September 2008 / Accepted 22 May 2009 / Available online 28 May 2009. Corresponding author: Leticia Quagliotto - letty@iibce.edu.uy Funding information: This work was financially supported by the LIA-INIA 028 Project, in the frame of the "Programa de Servicios Agropecuarios 1131-OC-UR (BID-MGAP-INIA)".  aABSTRACT. Alfalfa (Medicago sativa) is one of the most important crops used in Uruguay for livestock feeding. Seedling diseases, particularly damping-off, are a critical factor which limits its establishment. Three native Pseudomonas fluorescens strains, UP61.2, UP143.8 and UP148.2, previously isolated from Lotus corniculatus, were evaluated to determine their efficacy as biological control agents for alfalfa seedling diseases in the field. Their compatibility with the alfalfa-Sinorhizobium meliloti symbiosis was also assessed. In growth chamber conditions seed inoculation with Pseudomonas strains did not affect different parameters of alfalfa-rhizobium symbiosis as shown by nodulation rate and shoot dry weight of plants. The presence of the commercial inoculant strains of S. meliloti did not impair colonization by the P. fluorescens and vice versa. In field trials the dynamics of rhizobial rhizospheric populations were not affected by the presence of P. fluorescens. Each P. fluorescens strain successfully colonized alfalfa roots at adequate densities for biocontrol activity. Results showed that P. fluorescens strains provided a 10-13% increase in the number of established plants relative to the control, an intermediate result compared to the fungicide treatment (24%). The alfalfa above-ground biomass was increased by 13% and 15-18% in the presence of the fungicide and P. fluorescens strains, respectively. Therefore, results from this study demonstrated that the three P. fluorescens strains provided effective control against soil-borne pathogens and suggest a potential use in the development of a commercial inoculant to be applied for the control of legume seedling diseases.  © 2009 Elsevier Inc. All rights reserved.  aCONTROL BIOLÓGICO  aMEDICAGO SATIVA  aPSEUDOMONAS FLUORESCENS  aBiological control agent  aDamping-off  aField trials  aGrowth chamber conditions1 aAZZIZ, G.1 aBAJSA, N.1 aVAZ, P.1 aPÉREZ, C.1 aDUCAMP, F.1 aCADENAZZI, M.1 aALTIER, N.1 aARIAS, A.  tBiological Control, October 2009, Volume 51, Issue 1, Pages 42-50. Doi: https://doi.org/10.1016/j.biocontrol.2009.05.006