TY - JOUR
T1 - Rarity of Pseudomonas agarici on Edible Mushrooms Associated with Susceptibility to Biological Competition
AU - Moallem, Mahsa
AU - Hamidizade, Mozhde
AU - Taghavi, S. Mohsen
AU - Aeini, Milad
AU - Abachi, Hamid
AU - Haghighi, Shahrad
AU - Soleimani, Ardavan
AU - Hockett, Kevin L.
AU - Bull, Carolee Theresa
AU - Osdaghi, Ebrahim
N1 - Publisher Copyright:
© 2024 The American Phytopathological Society.
PY - 2024/9
Y1 - 2024/9
N2 - Taxonomically diverse Pseudomonas species induce bacterial blotch of edible mushrooms around the world. Pseudomonas tolaasii, [P. gingeri], and P. agarici are dominant mycopathogenic pseudomonads in mushroom production farms. In this study, among 216 mycopathogenic bacterial strains isolated from edible mushrooms in Iran, 96 strains were identified as Pseudomonas spp., while only three strains were preliminarily identified as P. agarici. Multilocus sequence analysis showed that only one strain (FH2) authentically belonged to P. agarici, while the other two strains either belonged to [P. gingeri] or represented a unique phylogenetic clade. The three strains also differed from each other in phenotypic characteristics, for example, production of fluorescent pigment and the reaction to tolaasin produced by P. tolaasii. Pathogenicity assays under a controlled environment showed that the symptoms induced by authentic P. agarici were far less severe than those caused by the predominant species P. tolaasii. Furthermore, coinoculation of P. agarici with three bacterial pathogens that are prevalent in Iran on mushroom caps, that is, P. tolaasii, Ewingella americana, and Mycetocola sp., resulted in the development of combined symptoms representing characteristics of both pathogens. The antibiosis assay showed that tolaasin-producing strains of P. tolaasii could inhibit the growth of P. agarici, while tolaasin-negative strains of the same species were unable to do so. This led us to the hypothesis that the inhibitory effect of P. tolaasii on P. agarici is driven by tolaasin production in the former species. This inhibitory effect is also associated with the rarity of P. agarici in natural conditions.
AB - Taxonomically diverse Pseudomonas species induce bacterial blotch of edible mushrooms around the world. Pseudomonas tolaasii, [P. gingeri], and P. agarici are dominant mycopathogenic pseudomonads in mushroom production farms. In this study, among 216 mycopathogenic bacterial strains isolated from edible mushrooms in Iran, 96 strains were identified as Pseudomonas spp., while only three strains were preliminarily identified as P. agarici. Multilocus sequence analysis showed that only one strain (FH2) authentically belonged to P. agarici, while the other two strains either belonged to [P. gingeri] or represented a unique phylogenetic clade. The three strains also differed from each other in phenotypic characteristics, for example, production of fluorescent pigment and the reaction to tolaasin produced by P. tolaasii. Pathogenicity assays under a controlled environment showed that the symptoms induced by authentic P. agarici were far less severe than those caused by the predominant species P. tolaasii. Furthermore, coinoculation of P. agarici with three bacterial pathogens that are prevalent in Iran on mushroom caps, that is, P. tolaasii, Ewingella americana, and Mycetocola sp., resulted in the development of combined symptoms representing characteristics of both pathogens. The antibiosis assay showed that tolaasin-producing strains of P. tolaasii could inhibit the growth of P. agarici, while tolaasin-negative strains of the same species were unable to do so. This led us to the hypothesis that the inhibitory effect of P. tolaasii on P. agarici is driven by tolaasin production in the former species. This inhibitory effect is also associated with the rarity of P. agarici in natural conditions.
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U2 - 10.1094/PDIS-02-24-0374-RE
DO - 10.1094/PDIS-02-24-0374-RE
M3 - Article
C2 - 38679595
AN - SCOPUS:85204819817
SN - 0191-2917
VL - 108
SP - 2778
EP - 2787
JO - Plant disease
JF - Plant disease
IS - 9
ER -