Characterization of Alcaligenes faecalis strain AD15 indicating biocontrol activity against plant pathogens

Aim: This study investigated the bacterial diversity of dead insects collected from olive tree orchards widely cultivated in Tunisia. We aimed to explore metabolic diversity, screen enzymatic activities for biotechnological applications and carry out preliminary bioassays for bio-insecticide development. Methods and results: A total of 50 bacteria strains were randomly isolated from four different biotopes situated in Sfax (Tunisia). 16S rRNA gene sequencing was used to identify 24 species, and isolates were evaluated for enzymatic activity and antimicrobial potential. Nineteen of the total number of Bacillus strains have enzymatic activity compared to strains from the other genera (14/50). Our bacterial collection was evaluated for antimicrobial potential against bacterial and fungal isolates. Isolates B8-2 (Bacillus subtilis) showed strong antibacterial activities and isolates B2-3 (Bacillus licheniformis) and B10-1 (Serratia marcescens) showed the highest antifungal activity. Seventeen of the total number of isolates caused greater than 50% mortality rate of second and fourth instar larvae of Ephestia kuehniella. Conclusion: The selected species from olive orchards represent a broad spectrum of antimicrobial and insecticidal activities and can be considered promising resources in biological control. Significance and Impact of the Study: Bacteria isolated from olive pests in olive orchards were investigated for detecting their potential biotechnological applications.

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“…Alcaligenes faecalis has also been characterized for bacteriostatic and fungistatic activity against plant pathogens (Yokoyama et al . ).…”

Section: Discussionmentioning

confidence: 97%

Screening of bacterial isolates related to olive orchard pests in Tunisia using 16S ribosomal RNA and evaluation of their biotechnological potential

et al. 2018

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“…In the present study, other genera (Alcaligenes, Brevundimonas, Curtobacterium and Arthrobacter) were also strongly correlated with asymptomatic tissues. Although Alcaligenes include clinically relevant strains 52,53 , some studies have been reporting the bacteriostatic and fungistatic activity (biocontrol activity) of some members against an array of plant pathogens [54][55][56] . Species belonging to Brevundimonas were previously described to confer fitness advantages to host plants, being indicated as potential soil bioremediators 57 and plant growth promotors 58 .…”

Section: Discussionmentioning

confidence: 99%

Impact of plant genotype and plant habitat in shaping bacterial pathobiome: a comparative study in olive tree

Mina

Pereira

Lino-Neto

et al. 2020

Sci Rep

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Plant-inhabiting microorganisms interact directly with each other affecting disease progression.However, the role of host plant and plant habitat in shaping pathobiome composition and their implication for host susceptibility/resistance to a particular disease are currently unknown. For the elucidation of these questions, both epiphytic and endophytic bacterial communities, present in asymptomatic and symptomatic twigs from olive cultivars displaying different susceptibilities to olive knot (OK) disease, were investigated using culturing methods. OK disease was the main driver of the bacterial community, causing changes on their diversity, abundance and composition. OK disease effect was most notorious on OK-susceptible cultivar and when considering the endophytic communities. plant habitat (epiphytes vs. endophytes) also contributed to the bacterial community assembling, in particular on symptomatic twigs (knots) of OK-susceptible cultivar. In contrast, host cultivar had little effect on the bacterial community composition, but OK-symptomatic twigs (knots) revealed to be more affected by this driver. Overall, the pathobiome seems to result from an intricate interaction between the pathogen, the resident bacteria, and the plant host. Specific bacterial genera were associated to the presence or absence of OK disease in each cultivar. Their ability to trigger and/or suppress disease should be studied in the future.

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“…A. faecalis also has the ability to neutralize environments contaminated by arsenite, because it can metabolize arsenite (AsO 2 Ϫ ) to the less harmful molecule arsenate (AsO 4 Ϫ ) (15,36,37). Moreover, some A. faecalis strains can produce a variety of plant growth-hastening hormones that are used as biofertilizers in agriculture (38). Here, we report that the Alcaligenes bacterium A. faecalis ZD02 has toxicity against M. incognita.…”

Section: Discussionmentioning

confidence: 83%

Alcaligenes faecalis ZD02, a Novel Nematicidal Bacterium with an Extracellular Serine Protease Virulence Factor

Lin

Zheng

et al. 2016

Appl Environ Microbiol

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Root knot nematodes (RKNs) are the world's most damaging plant-parasitic nematodes (PPNs), and they can infect almost all crops. At present, harmful chemical nematicides are applied to control RKNs. Using microbial nematicides has been proposed as a better management strategy than chemical control. In this study, we describe a novel nematicidal bacterium named Alcaligenes faecalis ZD02. A. faecalis ZD02 was isolated from Caenorhabditis elegans cadavers and has nematostatic and nematicidal activity, as confirmed by C. elegans growth assay and life span assay. In addition, A. faecalis ZD02 fermentation broth showed toxicity against C. elegans and Meloidogyne incognita. To identify the nematicidal virulence factor, the genome of strain ZD02 was sequenced. By comparing all of the predicted proteins of strain ZD02 to reported nematicidal virulence factors, we determined that an extracellular serine protease (Esp) has potential to be a nematicidal virulence factor, which was confirmed by bioassay on C. elegans and M. incognita. Using C. elegans as the target model, we found that both A. faecalis ZD02 and the virulence factor Esp can damage the intestines of C. elegans. The discovery that A. faecalis ZD02 has nematicidal activity provides a novel bacterial resource for the control of RKNs. P lant-parasitic nematodes (PPNs) are an important agricultural pest of many crops, and they cause agricultural losses amounting to an estimated $157 billion worldwide every year (1, 2). Root knot nematodes (RKNs; Meloidogyne spp.) are the most damaging crop PPNs, and they are capable of infecting almost all crops (2, 3). The management of RKNs is more difficult than that of other pests because RKNs are obligate root parasites of thousands of plant species, and most of the life cycle of RKNs is spent as parasites in the host roots (2, 4). The current means of controlling RKNs relies on chemical nematicides, which are often toxic and harmful to humans and the environment (3). In addition, chemical nematicides are generally expensive and cannot provide longterm RKN suppression (5).Biological control of RKNs is a better management strategy that avoids the potential environmental problems associated with the chemical control of RKNs. Indeed, the utilization of beneficial bacterial nematicides has been proposed as a sustainable alternative for RKN management, and bacterial nematicides are also regarded as economical and ecologically friendly nematicides for the control of RKNs (3, 6). Currently, for the bacterial control of RKNs, many problems remain, one of which is that nematicidal bacteria are relatively scarce. Only a few bacteria have been reported to possess nematicidal activity and to show potential for the biological control of RKNs. The typical nematicidal bacteria are Bacillus, Pseudomonas, and Pasteuria species (4, 7). Identifying novel nematicidal bacteria has become urgent for the bacterial control of RKNs and is of vital practical and economic significance.However, until now, it has been a challenge to isolate novel nematici...

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Characterization of Alcaligenes faecalis strain AD15 indicating biocontrol activity against plant pathogens

Cited by 22 publications

References 21 publications

Screening of bacterial isolates related to olive orchard pests in Tunisia using 16S ribosomal RNA and evaluation of their biotechnological potential

Screening of bacterial isolates related to olive orchard pests in Tunisia using 16S ribosomal RNA and evaluation of their biotechnological potential

Impact of plant genotype and plant habitat in shaping bacterial pathobiome: a comparative study in olive tree

Alcaligenes faecalis ZD02, a Novel Nematicidal Bacterium with an Extracellular Serine Protease Virulence Factor

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