title: Thermodependence of growth and enzymatic activities implicated in pathogenicity of two Erwinia carotovora subspecies (Pectobacterium spp.).
abstract: Erwinia carotovora subsp. atroseptica and Erwinia carotovora subsp. carotovora can cause substantial damage to economically important plant crops and stored products. The occurrence of the disease and the scale of the damage are temperature dependent. Disease development consists first of active multiplication of the bacteria in the infection area and then production of numerous extracellular enzymes. We investigated the effects of various temperatures on these two steps. We assayed the specific growth rate and the pectate lyase and protease activities for eight strains belonging to E. carotovora subsp. atroseptica and E. carotovora subsp. carotovora in vitro. The temperature effect on growth rate and on pectate lyase activity is different for the two subspecies, but protease activity appears to be similarly thermoregulated. Our results are in agreement with ecological data implicating E. carotovora subsp. atroseptica in disease when the temperature is below 20 degrees C. The optimal temperature for pathogenicity appears to be different from the optimal growth temperature but seems to be a compromise between this temperature and temperatures at which lytic activities are maximal.
authors.affiliation: Laboratoire de Microbiologie du Froid, UPRES 2123, Université de Rouen, Evreux, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Smadja
authors.forename: Xavier
authors.initials: X
authors.lastname: Latour
authors.forename: Sameh
authors.initials: S
authors.lastname: Trigui
authors.forename: Jean François
authors.initials: JF
authors.lastname: Burini
authors.forename: Sylvie
authors.initials: S
authors.lastname: Chevalier
authors.forename: Nicole
authors.initials: N
authors.lastname: Orange
mesh_terms: D018533:Biomass; D003720:Densitometry; D010450:Endopeptidases / Q000378:metabolism; D004798:Enzymes / Q000096:biosynthesis; D016973:Pectobacterium carotovorum / Q000201:enzymology* / Q000254:growth & development* / Q000472:pathogenicity; D010935:Plant Diseases / Q000382:microbiology*; D011133:Polysaccharide-Lyases / Q000378:metabolism; D013696:Temperature
chemical_list: D004798:Enzymes; D010450:Endopeptidases; D011133:Polysaccharide-Lyases; C023911:pectate lyase