Biological control of Pectobacterium carotovorum subsp. carotovorum, the causal agent of bacterial soft rot in vegetables, in vitro and in vivo tests

Hassan Abd-El-Khair,Hamdy I Seif El-Nasr,Tarek G Abdel-Gaied,Ahmed I Abdel-Alim,Maurice S Mikhail

doi:10.1186/s42269-021-00491-4

Hassan Abd-El-Khair, Hamdy I Seif El-Nasr + Show 3 more

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https://doi.org/10.1186/s42269-021-00491-4

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Abstract

BackgroundSeveral chemical bactericides were applied for controlling soft rot bacteria, Pectobacterium carotovorum subsp. carotovorum, which causes the destructive soft rot disease to many economically important vegetables, but because of their toxic hazards on human and environment became limit. The biocontrol was applied to control many plant pathogens. Therefore, this work is aimed to study the antagonistic activity of bacterial agents, i.e. Bacillus subtilis, Bacillus pumilus, Bacillus megaterium and Pseudomonas fluorescens, and fugal agents, i.e. Trichoderma harzianum, Trichoderma viride and Trichoderma virens, to control bacterial soft rot disease under in vitro and in vivo tests.ResultsThe tested treatments could protect the potato tubers against the development of soft rot. T. viride and T. virens were highly effective in reducing soft rot symptoms on inoculated potato tuber slices, when applied at the same time or 2 h before pathogen inoculation, while B. megaterium and T. harzianum were highly effective when applied at the same time or 2 h after pathogen inoculation. In whole potato tubers technique, B.pumilus highly protected the stored potato tuber under artificially infection conditions, than P. fluorescens, T. harzianum, B. subtilis, T. viride, T. virens and B. megaterium, respectively.ConclusionApplication of fungal agents or specify the bacterial species can play an important role in controlling bacterial soft rot disease in vegetables and increase the stored periods of potato tubers under storage conditions without any toxic effects.

Highlights

Several chemical bactericides were applied for controlling soft rot bacteria, Pectobacterium carotovorum subsp. carotovorum, which causes the destructive soft rot disease to many economically important vegetables, but because of their toxic hazards on human and environment became limit
In vitro tests The cultural filtrates of each B. subtilis, B. pumilus, B. megaterium and P. fluorescens could inhibit the bacterial growth of all tested P. carotovorum subsp. carotovorum strains, except Pcc6 & Pcc8 strains and Pcc9 & Pcc10 strains, which isolated from cucumber fruits and carrot roots, respectively (Table 2)
In this work we applied the cultural filtrates of B. subtilis, B. pumilus, B. megaterium, P. fluorescens, T. harzianum, T. viride and T. virens for testing their antagonistic activity against P. carotovorum subsp. carotovorum (15 strains) which isolated from some vegetables showing typical soft rot symptoms, viz. potato tubers, sweet potato roots, cucumber fruits, carrot roots, eggplant fruits and chili fruits (Mikhail et al 2019)

Summary

Introduction

Several chemical bactericides were applied for controlling soft rot bacteria, Pectobacterium carotovorum subsp. carotovorum, which causes the destructive soft rot disease to many economically important vegetables, but because of their toxic hazards on human and environment became limit. This work is aimed to study the antagonistic activity of bacterial agents, i.e. Bacillus subtilis, Bacillus pumilus, Bacillus megaterium and Pseudomonas fluorescens, and fugal agents, i.e. Trichoderma harzianum, Trichoderma viride and Trichoderma virens, to control bacterial soft rot disease under in vitro and in vivo tests. Carotovora) causes the destructive soft rot disease to many economically important vegetables such as carrot, cabbage, cucumber, eggplant, garlic, onion, pepper, potato, radish, sweet potato, squash and tomato (Opara and Asuquo 2016), where the biological control may be one of the good crop protection methods for controlling bacterial soft. Abd‐El‐Khair et al Bull Natl Res Cent (2021) 45:37 rot disease by application of Trichoderma spp., Bacillus spp. or Pseudomonas spp. which widely applied as biological agents against many soil-borne pathogens (Wulff et al 2003; Alabouvette et al 2006). Trichoderma asperellum could reduce the pathogenic effect of E. carotovora on the young seedlings of okra (Idowu et al 2016)

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