scholarly journals Plant-Growth-Promoting Bacteria (PGPB) against Insects and Other Agricultural Pests

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 861 ◽  
Author(s):  
Luca Ruiu

The interest in using plant-growth-promoting bacteria (PGPB) as biopesticides is significantly growing as a result of the discovery of new properties of certain beneficial microbes in protecting agricultural crops. While several rhizobial species have been widely exploited for their ability to optimize plant use of environmental resources, now the focus is shifted to species that are additionally capable of improving plant health and conferring resistance to abiotic stress and deleterious biotic agents. In some cases, PGPB species may directly act against plant pathogens and parasites through a variety of mechanisms, including competition, protective biofilm formation, and the release of bioactive compounds. The use of this type of bacteria is in line with the principles of ecosustainability and integrated pest management, including the reduction of employing chemical pesticides. Several strains of Bacillus, Paenibacillus, Brevibacillus, Pseudomonas, Serratia, Burkholderia, and Streptomyces species have been the subject of specific studies in this direction and are under evaluation for further development for their use in biological control. Accordingly, specific case studies are presented and discussed.

1998 ◽  
Vol 44 (2) ◽  
pp. 168-174 ◽  
Author(s):  
Yoav Bashan

Six strains of Azospirillum belonging to five species of plant growth-promoting bacteria (A. brasilense, A. lipoferum, A. amazonense, A. irakense, and A. halopraeference) did not cause visible disease symptoms on the roots or leaves of tomato, pepper, cotton, and wheat, failed to inhibit seed germination, and did not reduce plant dry weight when seven standard techniques for the inoculation of plant pathogens were used. Similar inoculation conditions with plant pathogens (Pseudomonas syringae pv. tomato, Xanthomonas campestris pv. vesicatoria, Xanthomonas campestris pv. translucens, and Xanthomonas campestris pv. malvacearum) induced typical disease symptoms. None of Azospirillum strains caused the hypersensitive reaction on eggplant, whereas all pathogens did. All Azospirillum strains increased phytoalexin production in all disease-resistant plant species to moderate levels, but the levels were significantly lower than those induced by the compatible pathogens. The various phytoalexins produced in plants had the capacity to inhibit growth of all Azospirillum strains. Azospirillum amazonense, A. irakense, and A. halopraeference had no apparent effect on plant growth, while A. brasilense and A. lipoferum increased the dry weight of all plant species. Under partial mist conditions, all Azospirillum strains were capable of colonizing leaf surfaces (103-107 cfu/g dry weight) regardless of the plant species. These results provide experimental evidence that Azospirillum sp. might be considered safe for the inoculation of several plant species.Key words: Azospirillum, beneficial bacteria, environmental protection, plant inoculation, plant growth-promoting bacteria.


Author(s):  
David Handy ◽  
Mary E. Hummerick ◽  
Anirudha R. Dixit ◽  
Anna Maria Ruby ◽  
Gioia Massa ◽  
...  

As we establish colonies beyond Earth, resupply missions will become increasingly difficult, logistically speaking, and less frequent. As a result, the on-site production of plants will be mission critical for both food production as well as complementing life support systems. Previous research on space crop production aboard the International Space Station (ISS) has determined that the spaceflight environment, though capable of supporting plant growth, is inherently stressful to plants. The combined stressors of this environment limits yield by inhibiting growth, as well as increasing susceptibility to infection by plant pathogens such as Fusarium spp. We propose that a consortium of space-viable, plant growth-promoting bacteria (PGPB) could assist in mitigating challenges to plant growth in a sustainable fashion. Here, we utilize biochemical and phenotypic assessments to identify potential PGPB derived from previously acquired isolates from the VEGGIE crop production system aboard the ISS. These assays confirmed the presence of bacteria capable of producing and/or interfering with plant hormones, facilitating plant uptake of high-value target nutrients for plants such as iron and phosphorus, and able to inhibit the growth of problematic fungal species. We discuss our findings with regards to their potential to support plant growth aboard spaceflight platforms as well as the Moon and Mars.


2021 ◽  
Vol 9 (9) ◽  
pp. 1988
Author(s):  
Hao Wang ◽  
Runjin Liu ◽  
Ming Pei You ◽  
Martin J. Barbetti ◽  
Yinglong Chen

A vast microbial community inhabits in the rhizosphere, among which, specialized bacteria known as Plant Growth-Promoting Rhizobacteria (PGPR) confer benefits to host plants including growth promotion and disease suppression. PGPR taxa vary in the ways whereby they curtail the negative effects of invading plant pathogens. However, a cumulative or synergistic effect does not always ensue when a bacterial consortium is used. In this review, we reassess the disease-suppressive mechanisms of PGPR and present explanations and illustrations for functional diversity and/or stability among PGPR taxa regarding these mechanisms. We also provide evidence of benefits when PGPR mixtures, rather than individuals, are used for protecting crops from various diseases, and underscore the critical determinant factors for successful use of PGPR mixtures. Then, we evaluate the challenges of and limitations to achieving the desired outcomes from strain/species-rich bacterial assemblages, particularly in relation to their role for plant disease management. In addition, towards locating additive or synergistic outcomes, we highlight why and how the benefits conferred need to be categorized and quantified when different strains/species of PGPR are used in combinations. Finally, we highlight the critical approaches needed for developing PGPR mixtures with improved efficacy and stability as biocontrols for utilization in agricultural fields.


2021 ◽  
Vol 13 (8) ◽  
pp. 4422
Author(s):  
Hafsa Cherif-Silini ◽  
Allaoua Silini ◽  
Ali Chenari Bouket ◽  
Faizah N. Alenezi ◽  
Lenka Luptakova ◽  
...  

Plant growth promoting bacteria (PGPB) have been the target of intensive research studies toward their efficient use in the field as biofertilizers, biocontrol, and bioremediation agents among numerous other applications. Recent trends in the field of PGPB research led to the development of versatile multifaceted PGPB that can be used in different field conditions such as biocontrol of plant pathogens in metal contaminated soils. Unfortunately, all these research efforts lead to the development of PGPB that failed to perform in salty environments. Therefore, it is urgently needed to address this drawback of these PGPB toward their efficient performance in salinity context. In this paper we provide a review of state-of-the-art research in the field of PGPB and propose a road map for the development of next generation versatile and multifaceted PGPB that can perform in salinity. Beyond soil desalinization, our study paves the way towards the development of PGPB able to provide services in diverse salty environments such as heavy metal contaminated, or pathogen threatened. Smart development of salinity adapted next generation biofertilizers will inevitably allow for mitigation and alleviation of biotic and abiotic threats to plant productivity in salty environments.


2018 ◽  
Vol 2 (4) ◽  
pp. 183-193 ◽  
Author(s):  
Alessandro Bergna ◽  
Tomislav Cernava ◽  
Manuela Rändler ◽  
Rita Grosch ◽  
Christin Zachow ◽  
...  

Endophytes with plant growth-promoting activity can improve the health and development of plants during all life stages. However, less is known about their stability and transmission across plant genotypes, habitats, and generations. By combining community and isolate analyses, we found that each plant habitat and genotype harbored distinct bacterial communities and plant growth-promoting bacteria (PGPB). Soil, root endosphere, and rhizosphere were the habitats with the highest bacterial diversity, while seeds hosted more selective communities. Seeds generated under field conditions showed traces of a bacterial community composition connected to the suppression of plant pathogens. In contrast, seeds of the successive generation grown in a pathogen-free and low-nutrient environment showed a predominance of bacteria that facilitate the uptake of nutrients. These modifications of the microbiome can be explained by an adaptation to prevalent environmental conditions. Cultivation approaches revealed microhabitat-specific PGPB that were assigned to various species of Bacillus, Stenotrophomonas, and Ralstonia. Tracking down these bacteria among the whole tomato plant allowed us to identify the seed as a primary vehicle of PGPB transmission. This previously undescribed vertical transmission of PGPB represents a strategy to maintain plant beneficial bacteria over generations and has an impact for the design of seed treatments.


Author(s):  
J. Monk ◽  
E. Gerard ◽  
S. Young ◽  
K. Widdup ◽  
M. O'Callaghan

Tall fescue (Festuca arundinacea) is a useful alternative to ryegrass in New Zealand pasture but it is slow to establish. Naturally occurring beneficial bacteria in the rhizosphere can improve plant growth and health through a variety of direct and indirect mechanisms. Keywords: rhizosphere, endorhiza, auxin, siderophore, P-solubilisation


2020 ◽  
Vol 53 (2) ◽  
Author(s):  
Muhammad Mubeen ◽  
Asghari Bano ◽  
Barkat Ali ◽  
Zia Ul Islam ◽  
Ashfaq Ahmad ◽  
...  

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