Is curtobacterium wilt biocontrol temperature dependent?/O biocontrole da murcha-de-curtobacterium e dependente da temperatura?

Abiotic stress interferes with plant-microbial interactions, but some microorganisms may buffer this interference. We investigated the interaction between temperature and bacterial wilt (Curtobacterium flaccumfaciens pv. flaccumfaciens--Cff) biocontrol and the ability of Bacillus subtilis strain ALB629 to colonize bean seedlings, to inhibit pathogen growth and to use different C and N sources. B. subtilis [ALB629.sup.rif], a mutant selected from the wild population of ALB629, was used to monitor plant colonization at 20°C and 30°C. [ALB629.sup.rif] was detected only in the plant roots ([10.sup.3,22] CFU [g.sup.-1]) at the lower temperature but colonized the roots, stems, and leaves ([10.sup.5.85], [10.sup.4.48], and [10.sup.4.01] CFU [g.sup.-1]), respectively, at 30°C. The area under the disease progress curve was also different at the two tested temperatures (p < 0.01). Nevertheless, the disease reduction using [ALB629.sup.rif]--treated seeds was similar: 71% and 75%, respectively, at 20 and 30°C (p < 0.01). A higher efficiency of C and N source utilization was observed at the higher temperature, but the antagonist inhibited Cff growth equally at either temperature in vitro. Based on our results, temperature interferes with pathogen and antagonist plant colonization, but the overall suppression of bacterial wilt appears to be stabilized by ALB629. Keywords: seed treatment, Phaseolus vulgaris, antibiosis, temperature, rhizobacteria, PGPR. Estresses abioticos interferem nas interacoes micro-organismo e, mas alguns microorganismos podem amenizar estes efeitos. Foi investigada a interacao entre temperatura e controle biologico da murcha-de-curtobacterium (Curtobacterium flaccumfaciens pv. flaccumfaciens--Cff) e a capacidade de Bacillus subtilis isolado ALB629 em colonizar plantulas de feijao, inibir o crescimento do patogeno e usar diferentes fontes de nutrientes. B. subtilis [ALB629.sup.rif], isolado mutante selecionado da populacao selvagem de ALB629 foi utilizado para rastrear a colonizacao da planta a 20 e 30°C. [ALB629.sup.rif] foi detectado apenas nas raizes ([10.sup.3,22] UFC [g.sup.-1]) na menor temperatura enquanto que a 30°C, [ALB629.sup.rif] colonizou as raizes, caules e folhas ([10.sup.5.85], [10.sup.4.48] e [10.sup.4.01] UFC [g.sup.-1]), respectivamente. A AACPD foi diferente nas duas temperaturas testadas (p < 0,01). No entanto, a reducao da doenca obtida pelo tratamento de sementes com [ALB629.sup.rif] foi semelhante de 71% e 75%, respectivamen