<b>Is curtobacterium wilt biocontrol temperature dependent?

Abstract

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 rif , a mutant selected from the wild population of ALB629, was used to monitor plant colonization at 20°C and 30°C. ALB629 rif was detected only in the plant roots (10 3.22 CFU g -1 ) at the lower temperature but colonized the roots, stems, and leaves (10 5.85 , 10 4.48 , and 10 4.01 CFU g -1 ), respectively, at 30ºC. The area under the disease progress curve was also different at the two tested temperatures (p < 0.01). Nevertheless, the disease reduction using ALB629 rif -treated seeds was similar: 71% and 75%, respectively, at 20 and 30ºC (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.O biocontrole da murcha-de-curtobacterium é dependente da temperatura?RESUMO. Estresses abióticos interferem nas interações micro-organismo e, mas alguns microorganismos podem amenizar estes efeitos. Foi investigada a interação entre temperatura e controle biológico da murcha-de-curtobacterium (Curtobacterium flaccumfaciens pv. flaccumfaciens -Cff) e a capacidade de Bacillus subtilis isolado ALB629 em colonizar plântulas de feijão, inibir o crescimento do patógeno e usar diferentes fontes de nutrientes. B. subtilis ALB629 rif , isolado mutante selecionado da população selvagem de ALB629 foi utilizado para rastrear a colonização da planta a 20 e 30ºC. ALB629 rif foi detectado apenas nas raízes (10 3,22 UFC g -1 ) na menor temperatura enquanto que a 30ºC, ALB629 rif colonizou as raízes, caules e folhas (10 5.85 , 10 4.48 e 10 4.01 UFC g -1 ), respectivamente. A AACPD foi diferente nas duas temperaturas testadas (p < 0,01). No entanto, a redução da doença obtida pelo tratamento de sementes com ALB629 rif foi semelhante de 71% e 75%, respectivamente a 20 e 30ºC (p < 0,01). Uma maior eficiência de utilização de fontes de C e N foi observada na temperatura mais elevada, mas o antagonista igualmente inibiu o crescimento de Cff in vitro em qualquer temperatura. Portanto, a temperatura interfere na colonização da planta pelo patógeno e pelo antagonista, mas a supressão da murcha-de-curtabacterium de modo geral parece ser estabilizado por ALB629. 410 Martins et al.

Impact of Seed Exudates on Growth and Biofilm Formation of Bacillus amyloliquefaciens ALB629 in Common Bean

“…To select the ALB629 with the selection marker, increasing amendments of both antibiotics were added to the LB medium up to 100 ppm at each bacterial culture. The spontaneous mutant strain was previously compared to the wild type for its growth and biological control efficacy and the mutation did not impact such variables ( Martins et al, 2014 ).…”

“…ALB629 has been proved to promote common bean growth as well as control bacterial wilt ( Curtobacterium flaccumfaciens pv. flaccumfaciens ) even under heat stress ( Martins et al, 2013 , 2014 ).…”

Bacterial wilt of dry beans caused by Curtobacterium flaccumfaciens pv. flaccumfaciens: A new threat from an old enemy

“…The bacterial wilt reduction has ranged from 42% to 76% (Martins et al , ). Environmental temperature (20 vs. 30 °C) interferes with the colonization of plants with the pathogen and antagonist, while the suppression of bacterial wilt using the B. cereus strain ALB629 was similar at the two temperatures (Martins et al , ). Furthermore, soaking common bean seeds in a suspension (3 × 10 8 cfu/ml) of Pantoea agglomerans resulted in thorough endophytic colonization of the entire bean seedling from root to apical stem 7 days post‐inoculation and resulted in the reduction of bacterial wilt severity in greenhouse conditions (Hsieh et al ., ).…”

The Role of Plant-Associated Bacteria, Fungi, and Viruses in Drought Stress Mitigation

“…Irrigation, however, is technical and cannot always be adopted by growers, and drought-tolerant cultivars are not always prefered by growers and consumers. Alternatively, plant-associated microbes and viruses can enhance crop productivity under climate change conditions, providing a sustainable approach to stress resistance ( Xu et al, 2008 ; Martins et al, 2014 , 2018 ; Nadeem et al, 2014 ). While many studies have elucidated how plant selection for a particular microbiome assemblage can be an important strategy for addressing biotic stressors ( Mendes et al, 2011 ; Carríon et al, 2019 ), studies are just beginning to address the role of microbial communities in abiotic stress alleviation ( de Vries et al, 2020 ).…”