Bacteriophytochromes From Pseudomonas syringae pv. tomato DC3000 Modulate Epiphytic Growth And Pathogenicity

ANALÍA CARRAU; WOLFGANG GÄRTNER; LAURA MOYANO; IVANA KRAISELBURD; SILVANA PETROCELLI; ELENA G. ORELLANO

Aguas de lindoias

Congreso; Reunião Anual da SBBq; 2017

BACTERIOPHYTOCHROMES FROM PSEUDOMONAS SYRINGAE PV. TOMATO DC3000 MODULATE EPIPHYTIC GROWTH AND PATHOGENICITYLaura Moyano1, Analía Carrau1, Silvana Petrocelli1, Ivana Kraiselburd1, Wolfgang Gärtner2 and Elena G. Orellano11Instituto de Biología Molecular y Celular de Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK) Rosario, Argentina; 2Max-Planck-Institute for Chemical Energy Conversion, D-45470 Mülheim, Germany.All living organisms have evolved the ability to perceive and respond to light. Photoreceptor proteins are the responsible for light perception and they are classified in six families: rhodopsins, phytochromes, xanthopsins, cryptochromes, LOV (Light, Oxygen and Voltage) and BLUF (Blue-Light sensing Using Flavin) proteins. Several reports indicate that light modulates physiological characteristics in photosynthetic and non-photosynthetic microorganisms. Moreover, recent studies revealed that light is implicated in the regulation of several physiological features in many important plant pathogens, e.g., Pseudomonas syringae pv. syringae, Pseudomonas syringae pv. tomato (Psto), Pseudomonas cichorii, and Xanthomonas citri subsp. citri. Psto is a Gram-negative hemibiotrophic plant pathogen which causes the bacterial speck in tomato plants. Psto presents two lifestyles, an initial epiphytic phase upon arrival on the surface of a healthy plant and an endophytic phase in the apoplast after entering into the plant through natural openings and fortuitous wounds. The Psto genome contains one gene encoding a LOV protein and two genes encoding phytochromes (PSPTO_1902 and PSPTO_2652). The aim of this work was to study the role of light and Psto phytochromes in the bacterial physiology and during the interaction with host plants. For that purpose we evaluated the effect of mutant strains, lacking a functional bphP1 or bphP2 gene, in comparison to the wild-type strain and the complemented strains on the bacterial physiological features and the interaction between Psto and tomato plants. According to our results, Psto phytochromes are implicated in the control of some features related with the epiphytic phase, such as motility, biofilm formation, adhesion and biosurfactant production. Red light and Psto phytochromes play an important role during the epiphytic fitness, causing a reduction in the virulence. In addition, light regulates the endophytic phase in Psto controlling the type two secretion system and the disease symptoms in infiltrated leaves.