Diversity of Pectobacterium strains by biochemical, physiological, and molecular characterization

Adelaide Siqueira Silva,José Magno Queiroz Luz,Tâmara Prado De Morais,Nilvanira Donizete Tebaldi

doi:10.14393/bj-v36n2a2020-46256

Adelaide Siqueira Silva, José Magno Queiroz Luz + Show 2 more

Open Access

https://doi.org/10.14393/bj-v36n2a2020-46256

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Journal: Bioscience Journal	Publication Date: Feb 11, 2020
Citations: 3	License type: cc-by

Affiliation: Universidade Federal de Uberlândia

Abstract

Pectobacterium is a complex taxon of strains with diverse characteristics. It comprises several genera, including Erwinia, Brenneria, Pectobacterium, Dickeya, and Pantoea. Pectobacterium and Dickeya cause diseases in a wide range of plants, including potatoes, where they are causative agents of soft rot in tubers and blackleg in field-grown plants. Characterizing Pectobacterium species allows for the analysis of the diversity of pectinolytic bacteria, which may support control strategies for plant bacterial diseases. The aim of this study was to perform biochemical, physiological, and molecular characterizations of Pectobacterium spp. from different sites and host plants. The isolated strains were characterized by the glucose fermentation test, Gram staining, catalase activity, oxidase activity, growth at 37 ºC, reducing substances from sucrose, phosphatase activity, indole production, acid production from different sources (sorbitol, melibiose, citrate, and lactose), pathogenicity in potato, and hypersensitivity reactions. Molecular characterization was performed with species-specific primers ECA1f/ECA2r and EXPCCF/EXPCCR, which identify P. atrosepticum and P. carotovorum subsp. carotovorum (Pcc), respectively, and with primers 1491f/L1RA/L1RG and Br1f/L1RA/L1RG that differentiate Pcc from Dickeya chrysanthemi and from P. carotovorum subsp. brasiliensis. The strains were identified as belonging to the genus Pectobacterium, though they did not fit the biochemical nor the molecular classification standards for subspecies differentiation, indicating significant diversity among the strains.

Highlights

Potato propagation is potentially associated with the dissemination of pathogens, including bacteria belonging to the genus Pectobacterium
Detection, identification, and characterization of Pectobacterium species can be accomplished by using selective culture medium containing pectate (CUPEELS; KELMAN, 1974), by biochemical, physiological (DE BOER; KELMAN, 2001), molecular (TOTH; AVROVA; HYMAN, 2001), and serological tests (ALLAN; KELMAN, 1977), and by biological baits (TAKATSU; MELO; GARCIA, 1981)
Latent infection in tubers can be detected by incubation, lenticella sampling (DE BOER; KELMAN, 1975), and direct seeding of tuber extract dilutions on Bulmer crystal violet pectate medium (PÉROMBELON; KELMAN, 1987)

Summary

Introduction

Potato propagation is potentially associated with the dissemination of pathogens, including bacteria belonging to the genus Pectobacterium. These bacteria, the causative agents of blackleg and soft rot diseases (LOPES; QUEZADO-DUVAL, 2001), are capable of producing pectinolytic enzymes that lead to plant death in the field and rot in potato tubers under either field or storage conditions. Controlling the diseases is difficult, since the bacteria present large genetic variability and can survive in a large number of host plants. This makes it difficult to select resistant cultivars (BRISOLLA et al, 2002). The pathogenicity test can be carried out by inoculating the bacterium in potato tubers or by stem inoculation of potato plantlets (DICKEY; KELMAN, 1988)

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