Pseudomonas corrugate, a Pathogen of Tomato, Isolated from Symptomless Alfalfa Roots

Abstract

Pseudomonas corrugata, the causal agent of a serious disease of roots, rotted onion scales and produced necrotic lesions on lettuce leaves, greenhouse-grown tomato plants in England, was isolated from healthy but potato tuber tissue was not rotted. Attempts to isolate strains of the roots of greenhouse-grown alfalfa plants in the USA. Inoculations of organism from field-grown alfalfa plants failed. Therefore, its role in root bacterial strains from both alfalfa and tomato into tomato stems induced and crown diseases of alfalfa was not determined. This is the first report on symptoms similar to those originally described for the disease. Strains from the occurrence of P. corrugata in the USA. both sources caused localized necrosis when injected into alfalfa stems and In 1974 1 reported (10) the isolation of pathogenic bacteria Pathogenicity tests.-For these tests, the bacteria that had been resembling Pseudomonas cepacia from surface-sterilized cross stored in sterile tap water were transferred to YDCA (glucose, 20 g; sections of healthy alfalfa roots that were being used to study the yeast extract, 10 g; CaCO 3 , 20 g; and agar, 15 g; in 1 L of H 2 0) and interactions between strains of Corynebacterium insidiosum. The allowed to grow for 48 hr before use. The roots of 1-yr-old alfalfa bacteria produced a dark blue pigment which was evident both in plants (Medicago sativa L. 'Saranac') were freed of soil by washing. the colonies and in the root tissue beneath the colonies. That report Three 5-mm diameter roots of each plant were inoculated by listed some similarities with P. cepacia, such as production of wounding with a teasing needle smeared with bacteria. Surface yellow pigment, nonfluorescence, presence of poly-/3-hydroxy-water from sterile medium was used as a control. Each isolate was butyrate granules, and showing an oxidase positive reaction. The inoculated into four separate plants which were transplanted into alfalfa strains differed from P. cepacia in being unable to grow at 41 sterile sand and covered with a plastic bag for 24 hr. Five days later C and being able to break down gelatin rapidly. the roots were washed free of sand and evaluated for disease A similar bacterial strain, isolated from a diseased tomato stem, development. was described by Scarlett, et al (15) who concluded that the new The stems of greenhouse-grown alfalfa, tomato (Lycopersicon strain was different from the P. cepacia group. They established a esculentum Mill.), and onion (Allium cepa L.) were inoculated by new species, Pseudomonas corrugata Roberts and Scarlett, and injection with a suspension of two of the alfalfa strains and NCPPB designated isolate NCPPB 2445 as the type culture. 2445. The inocula in tap water were adjusted to a constant level of For this study an isolate of the type culture was obtained through 20% transmission at 420 nm ("-10 X 10' cells per ml) before use. The the courtesy of Pauline Roberts. plants were bagged for 24 hr and left on a greenhouse bench. This report is a summary of different biochemical, ...

Pseudomonas corrugata and Pseudomonas marginalis associated with the collapse of tomato plants in rockwool slab hydroponic culture

“…Scarlett et al (1978) reported that P. corrugata did not rot onion slices. On the other hand, in the test of Lukezic (1979) this bacterium was capable of rotting onion sections if inoculated onto a cut surface. As regards P. marginalis (sensu stricto), this fluorescent pseudomonad serves as a typical species indicating the positive pectolytic activity.…”

Phenotypic heterogeneity of Pseudomonas corrugata strains from southern Italy

“…1988) and chrysanthemum with pith necrosis (Fiori 1992), in biochemical characteristics as well as in pigment prosoil (Scortichini 1989), water (Scarlett et al 1978), sympduction and colony morphology (Siverio et al 1993). High tomless alfalfa roots (Lukezic 1979), and wheat rhizosphere heterogeneity was also observed in reactions to three antisera (Roberts and Brewster 1991). It can cause significant losses, and the presence of at least 11 lipopolysaccharide profiles but particularly in tomatoes grown in unheated greenhouses no correlation to the origin of isolation was reported (Siverio where a great difference in temperature between night and et al 1993).…”

“…corrugata has already been described as closely related to some fluorescent pseudodifferent biochemical protein profile or react with different antisera. Despite the variability observed among strains, the monads on the basis of its phenotypic characteristics (Lukezic 1979), DNA-rRNA homology (De Vos et al 1985) and fatty phenotypic characteristics of Ps. corrugata clearly distinguish this group from other species.…”

Contamination

“…It is not uncommon that the explant material can harbor internal microorganisms (Armstrong, 1973;Tabor et al, 1991;Misaghi & Donndelinger, 1990;Petit et al, 1968;Gagne et al, 1987;Philipson & Blair, 1957;Lukezic, 1979;Sanford, 1948;DeBoer & Copeman, 1974;Hollis, 1951;Sturdy & Cole, 1974;Meneley & Stanghellini, 1974, 1975Samish et al, 1963;Bugbee et al, 1987;Tervet & Hollis, 1948;Knauss & Miller, 1978;DePrest & Van Vaerenbergh, 1980;Schreiber et al, 1996). When this is the case, it can be very difficult to establish clean cultures.…”