| dc.description.abstract | Se consigna que la agalla de la corona causada por A. tumefaciens es un nicho ecológico altamente específico; sin embargo, nuestra hipótesis sugiere que dentro de este tejido se albergan bacterias nativas con potencial antagonismo contra A. tumefaciens. El objetivo de este estudio fue explorar la densidad de poblaciones bacterianas nativas en la agalla de la corona de frambuesa y comprobar su potencial antagonismo. Se aislaron poblaciones bacterianas dentro de seis muestras de agallas de frambuesa var. elvira. Se identificó a A. tumefaciens mediante caracterización bioquímica, patogenicidad y por la secuenciación del gen virD2. Las densidades de poblaciones bacterianas totales se calcularon por el conteo directo de placas en medios agar nutritivo, R2A y Pseudomonas-agar, se evaluó el antagonismo de las bacterias nativas en la agalla de la corona in vitro contra A. tumefaciens mediante el índice de eficiencia antagónica; las bacterias con potencial antagónico fueron empleadas para el modelo in vivo. Se emplearon plantas de jitomate var. rámses, tratadas por inmersión de raíces en suspensión de bacterias antagónicas 1 x 107 UFC, mediante dos tipos de inoculación del patógeno, por herida y por sustrato, cuatro tratamientos con cinco repeticiones en un diseño completamente al azar manteniendo el experimento bajo condiciones de invernadero. La densidad poblacional dentro de la agalla de corona es poco diversa, identificando por amplificación del gen 16S rARN Pseudomonas spp (61.5 %), Bacillus spp (15.3 %), Alcaligenes faecalis (15.3 %) y Delftia sp (7.69 %). La bacteria con mayor índice de eficiencia antagónica in vitro contra A. tumefaciens fue Alcaligenes faecalis, seguido de Delftia sp, (p ≤ 0.05). La inoculación in vivo de las antagonistas no suprimió la infección; sin embargo, reducen significativamente (p ≤ 0.05) la severidad de tumores en el tallo de las plantas, siendo Alcaligenes faecalis la bacteria más eficiente contra A. tumefaciens. _______________ BIOLOGICAL CONTROL OF AGROBACTERIUM TUMEFACIENS MEDIATED BY NATIVE BACTERIA IN THE CROWN GALL. ABSTRACT: Crown gall caused by A. tumefaciens is reported to be a highly specific ecological niche; however, our hypothesis suggests that native bacteria with potential antagonism against A. tumefaciens are harbored within this tissue. The objective of this study was to explore the density of native bacterial populations in the raspberry crown gall and to verify their potential antagonism. Bacterial populations were isolated within six gall samples of raspberry var. elvira. A. tumefaciens was identified by biochemical characterization, pathogenicity, and by sequencing of the virD2 gene. The densities of total bacterial populations were calculated by direct plate count in nutrient agar, R2A and Pseudomonas-agar media, the antagonism of native bacteria in the crown gall in vitro against A. tumefaciens was evaluated by means of the efficiency index antagonistic; bacteria with antagonistic potential were used for the in vivo model. Tomato plants var. ramses, treated by immersion of roots in suspension of antagonistic bacteria 1 x 107 CFU, by means of two types of inoculation of the pathogen, by wound and by substrate, four treatments with five repetitions in a completely randomized design, maintaining the experiment under greenhouse conditions. The population density within the crown gall is not very diverse, identifying by amplification of the 16S rRNA gene Pseudomonas spp (61.5%), Bacillus spp (15.3%), Alcaligenes faecalis (15.3%) and Delftia sp (7.69%). The bacterium with the highest rate of in vitro antagonistic efficiency against A. tumefaciens was Alcaligenes faecalis, followed by Delftia sp, (p ≤ 0.05). In vivo inoculation of the antagonists did not suppress the infection; however, they significantly reduce (p ≤ 0.05) the severity of tumors in the stem of plants, with Alcaligenes faecalis being the most efficient bacteria against A. tumefaciens. | es_MX |
