A bacterial endophyte from apoplast fluids protects canola plants from different phytopathogens via antibiosis and induction of host resistance.
Romero, F. M., Rossi, F. R., Garriz, A., Carrasco, P. and Ruiz, O. A.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico Chascomus, Universidad Nacional de General San Martin-Consejo Nacional de Investigaciones Cientificas y Tecnicas (IIB-INTECH/UNSAM-CONICET) , Av. Intendente Marino Km 8,200 , Chascomus, Buenos Aires, Argentina , 7130 ; mromero@intech.gov.ar.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico Chascomus, Universidad Nacional de General San Martin-Consejo Nacional de Investigaciones Cientificas y Tecnicas (IIB-INTECH/UNSAM-CONICET), Chascomus, Argentina ; francorossi@intech.gov.ar.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico Chascomus, Universidad Nacional de General San Martin-Consejo Nacional de Investigaciones Cientificas y Tecnicas (IIB-INTECH/UNSAM-CONICET), Chascomus, Argentina ; garriz@intech.gov.ar.
Facultat de Ciencies Biologiques, Universitat de Valencia, Valencia, Spain., Departament de Bioquimica i Biologia Molecular, Valencia, Spain ; pedro.carrasco@uv.es.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico Chascomus, Universidad Nacional de General San Martin-Consejo Nacional de Investigaciones Cientificas y Tecnicas (IIB-INTECH/UNSAM-CONICET), Chascomus, Argentina.
Instituto de Fisiologia y Recursos Geneticos Vegetales, Instituto Nacional de Tecnologia Agropecuaria (IFRGV-INTA), Cordoba, Argentina ; ruiz@intech.gov.ar.
Endophytic bacteria colonize inner plant tissues and thrive at the apoplast, which is considered its main reservoir. Since this niche is the place where the main molecular events take place between beneficial and pathogenic microorganisms, the aim of this work was to characterize culturable endophytic bacteria from apoplastic fluids obtained from field-grown canola leaves and analyse their potential for biological control of diseases caused by Xanthomonas campestris, Sclerotinia sclerotiorum and Leptosphaeria maculans. Dual culture analysis indicated that three isolates (Apo8, Apo11 and Apo12) were able to inhibit the growth of all three phytopathogens. Sequencing of the 16S rRNA and rpoD genes of these isolates revealed that they are closely related to Pseudomonas viridiflava. One of the isolates, Apo11, was able to diminish the propagation of X. campestris in whole plants assays. At the same time, Apo11 inoculation reduced the necrotic lesions provoked by S. sclerotiorum on canola leaves. This protective effect might be due to the induction of resistance in the host mediated by salicylic and jasmonic acid signalling pathways and/or the production of compounds with antimicrobial activity. At the same time, Apo11 inoculation promoted canola plant growth. Thus, the isolate characterized in this work has several desirable characteristics, which make it a potential candidate for the formulation of biotechnological products to control plant diseases and/or promote plant growth.
Phytopathology : en prensa (2018)