scholarly journals Cyanobacteria: A Natural Source for Controlling Agricultural Plant Diseases Caused by Fungi and Oomycetes and Improving Plant Growth

Horticulturae ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 58
Author(s):  
Hillary Righini ◽  
Ornella Francioso ◽  
Antera Martel Quintana ◽  
Roberta Roberti

Cyanobacteria, also called blue-green algae, are a group of prokaryotic microorganisms largely distributed in both terrestrial and aquatic environments. They produce a wide range of bioactive compounds that are mostly used in cosmetics, animal feed and human food, nutraceutical and pharmaceutical industries, and the production of biofuels. Nowadays, the research concerning the use of cyanobacteria in agriculture has pointed out their potential as biofertilizers and as a source of bioactive compounds, such as phycobiliproteins, for plant pathogen control and as inducers of plant systemic resistance. The use of alternative products in place of synthetic ones for plant disease control is also encouraged by European Directive 2009/128/EC. The present up-to-date review gives an overall view of the recent results on the use of cyanobacteria for both their bioprotective effect against fungal and oomycete phytopathogens and their plant biostimulant properties. We highlight the need for considering several factors for a proper and sustainable management of agricultural crops, ranging from the mechanisms by which cyanobacteria reduce plant diseases and modulate plant resistance to the enhancement of plant growth.

2020 ◽  
Vol 8 (7) ◽  
pp. 1037 ◽  
Author(s):  
Dragana Miljaković ◽  
Jelena Marinković ◽  
Svetlana Balešević-Tubić

Bacillus spp. produce a variety of compounds involved in the biocontrol of plant pathogens and promotion of plant growth, which makes them potential candidates for most agricultural and biotechnological applications. Bacilli exhibit antagonistic activity by excreting extracellular metabolites such as antibiotics, cell wall hydrolases, and siderophores. Additionally, Bacillus spp. improve plant response to pathogen attack by triggering induced systemic resistance (ISR). Besides being the most promising biocontrol agents, Bacillus spp. promote plant growth via nitrogen fixation, phosphate solubilization, and phytohormone production. Antagonistic and plant growth-promoting strains of Bacillus spp. might be useful in formulating new preparations. Numerous studies of a wide range of plant species revealed a steady increase in the number of Bacillus spp. identified as potential biocontrol agents and plant growth promoters. Among different mechanisms of action, it remains unclear which individual or combined traits could be used as predictors in the selection of the best strains for crop productivity improvement. Due to numerous factors that influence the successful application of Bacillus spp., it is necessary to understand how different strains function in biological control and plant growth promotion, and distinctly define the factors that contribute to their more efficient use in the field.


Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Wen Qing Yu ◽  
Peng Li ◽  
Feng Chao Yan ◽  
Gui Ping Zheng ◽  
Wen Zhi Liu ◽  
...  

AbstractProtein elicitors can induce plant systemic resistance to pathogens. In an earlier study, we cloned an EsxA gene from the plant growth-promoting rhizobacterium Paenibacillus terrae NK3-4 and expressed it in Pichia pastoris. In addition to being important for the pathogenicity of animal pathogens, EsxA can also induce an immune response in animals. While, we found the exogenously expressed EsxA has the activity of elicitor, which can trigger hypersensitive response and reactive oxygen species burst in leaves as well as enhanced rice plant growth. The effects of EsxA on seedling blight (Fusarium oxysporum) resistance and gene transcription, including pathogenesis-related (PR) genes in rice were evaluated. The germination rate was 95.0% for seeds treated with EsxA and then inoculated with F. oxysporum, which was 2.8-times higher than that of F. oxysporum-infected control seeds that were not treated with EsxA (Con). The buds and roots of EsxA-treated seedlings were 2.4- and 15.9-times longer than those of Con seedlings. The plants and roots of seedlings dipped in an EsxA solution and then inoculated with F. oxysporum were longer than those of the Con seedlings. Theplant length, number of total roots, and number of white roots were respectively 23.2%, 1.74-times, and 7.42-times greater for the seedlings sprayed with EsxA and then inoculated with F. oxysporum than for the Con seedlings. The EsxA induction efficiency (spray treatment) on seedling blight resistance was 60.9%. The transcriptome analysis revealed 1137 and 239 rice genes with EsxA-induced up-regulated and down-regulated transcription levels, respectively. At 48 h after the EsxA treatment, the transcription of 611 and 160 genes was up-regulated and down-regulated, respectively, compared with the transcription levels for the untreated control at the same time-point. Many disease resistance-related PR genes had up-regulated transcription levels. The qPCR data were consistent with the transcriptome sequencing results. EsxA triggered rice ISR to seedling blight and gene differential transcription, including the up-regulated transcription of rice PR genes. These findings may be relevant for the use of EsxA as a protein elicitor to control plant diseases.


2020 ◽  
Vol 19 (6) ◽  
pp. 31-45
Author(s):  
Mahendra Rai ◽  
Aniket Gade ◽  
Beata Zimowska ◽  
Avinash P. Ingle ◽  
Pramod Ingle

Endophytes are those inhabiting in plants without causing any apparent loss to the host plant. Phoma is a ubiquitously found genus of fungi in soil, water and air. Endophytic Phoma spp. are distributed with high specific diversity, those occur in plants and are mainly responsible for the production of a vast range of secondary metabolites. These secondary metabolites or the bioactive compounds have demonstrated a wide range of activity ranging from antibacterial, antifungal, antiviral, algicidal, cytotoxic, antitubercular and plant growth promoting, etc. Bioactive compounds are produced by Phoma herbarum, P. sorghina, P. exigua, P. macrostoma, P. medicaginis, P. betae, P. tropica and others. The present review emphasizes on different species of endophytic Phoma as novel source of bioactive compounds, and their applications in medicine and agriculture are documented.


Author(s):  
V.Z. Nguyen ◽  
T.O. Dao ◽  
T.H. Nguyen ◽  
E.A. Kalashnikova

Перец овощной (Capsicum annuum L.) является одной из основных возделываемых культур Вьетнама в связи с широким его использованием в пищевой промышленности в качестве приправы. Это делает данное растение важной сельскохозяйственной культурой, которая приносит значительный доход вьетнамским фермерам. Однако на плантациях перца часто наблюдается появление и развитие болезни ризоктониоз, которую вызывает патогенный гриб Rhizoctonia solani, а также наблюдается бактериальное увядание, вызываемое бактерией Ralstonia solanacearum. Поражение ризоктониозом, одной из самых вредных болезней перца, может наблюдаться в любой фазе развития растений. Известно, что ризобактерии способны не только стимулировать рост растений, но и подавлять развитие болезней. Цель данной работы выделение из ризосферы растений перцев бактерий, ингибирующих развитие Rhizoctonia solani и оценка in vitro их фосфатрастворяющей активности и секреции сидерофора. Из различных почвенных образцов, отобранных с полей коммун Ан Хань, Ан Нинь, Кунь Ми, района Кунь Фу, провинции Тхай Бинь, выделено 48 штаммов бактерий, из которых были отобраны 5 штаммов (АТ 16 VK 4.7 VK 4.8 VK 4.12 VK 4.13), обладающих высокой ингибирующей активностью по отношению к Rhizoctonia solani, которая составила 11,11 62,22. Показано, что эти штаммы обладают способностью синтезировать такой фитогормон, как индолилуксусную кислоту (ИУК) (с 9,54 мг/мл до 31,06 мг/мл), растворять труднорастворимые фосфатные соединения и секрецировать сидерофор. Из 5 выделенных штаммов только у штамма АТ 16 данные способности выражены более сильно. Полученные результаты свидетельствуют о том, что изученные штаммы обладают хорошим потенциалом для использования их в качестве биологических агентов, контролирующих развитие R. solani на растениях перца.Peppers or chilli (Capsicum annuum L.) is widely grown in Vietnam because they bring considerable income to farmers. On pepper fields, diseases such as rhizoctonia, Rhizoctoniasolani caused by fungus, bacterial wilt by Ralstoniasolanacearum are often observed. Rhizoctoniasolani causes a wide range of significant diseases such as collar rot, root rot, damping offin horticultural and field crops.The diseases caused by rhizoctonia are one of the most harmful diseases on peppers, can be observed in any phase of plant development. Rhizobacteria that stimulate plant growth can be used to improve plant growth and suppress plant diseases. The purpose of this work is to isolate bacteria from the pepper rhizosphere that inhibit Rhizoctoniasolani and evaluate in vitro their phosphate solubilizing activity and production of siderophore. Of the different soil samples taken from the pepper fields of An Thanh, An Ninh, Quynh My, QuynhPhudistrict, ThaiBinh province, 48 bacterial strains were isolated. Of these, 5 strains (AT16, VK 4.7, VK 4.8, VK 4.12, VK 4.13) expressed as higher inhibitory Rhizoctoniasolani activity were selected. Their inhibitory activity is from 11.11 to 62.22. These strains have the ability to synthesize phytohormone IAA (from 9.54 g / ml to 31.06g / ml), solubilize the phosphate compounds and productsiderophore. Strain AT16 more effective expresses these abilities in comparison with 4 other strains. These results suggest that the selected strains have excellent potential for use as biologically controlled agents of R. solani on pepper plants (Capsicum annuum L.).


Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 453
Author(s):  
Imen Belgacem ◽  
Maria G. Li Destri Nicosia ◽  
Sonia Pangallo ◽  
Ahmed Abdelfattah ◽  
Massimo Benuzzi ◽  
...  

Although the Green Revolution was a milestone in agriculture, it was accompanied by intensive use of synthetic pesticides, which has raised serious concerns due to their impact on human and environmental health. This is increasingly stimulating the search for safer and more eco-friendly alternative means to control plant diseases and prevent food spoilage. Among the proposed alternatives, pomegranate peel extracts (PPEs) are very promising because of their high efficacy. In the present review, we discuss the complex mechanisms of action that include direct antimicrobial activity and induction of resistance in treated plant tissues and highlight the importance of PPE composition in determining their activity. The broad spectrum of activity, wide range of application and high efficiency of PPEs against bacterial, fungal and viral plant pathogens suggest a potential market not only restricted to organic production but also integrated farming systems. Considering that PPEs are non-chemical by-products of the pomegranate industry, they are perceived as safe by the public and may be integrated in circular economy strategies. This will likely encourage agro-pharmaceutical industries to develop commercial formulations and speed up the costly process of registration.


2021 ◽  
Author(s):  
Adrien Anckaert ◽  
◽  
Anthony Arguelles Arias ◽  
Grégory Hoff ◽  
Maryline Calonne-Salmon ◽  
...  

Biocontrol agents (BCAs) based on plant growth promoting rhizobacteria have recently been developed as alternatives to chemical pesticides. Among those beneficial bacteria, Bacillus spp. are one of the most promising BCAs. A wide range of bioactive secondary metabolites (BSMs) are involved in biocontrol via antibiosis to phytopathogens and/or via elicitation of systemic resistance in their host plants. This chapter illustrates the diversity of pathosystems in which BCA based on Bacillus spp. have proved effective. It describes the mechanisms underpinning this biocontrol activity via production of a wide range of enzymes, proteins and small-size BSMs. As these BSMs are clearly involved in pathogen control, we emphasise the importance of understanding the ecological factors influencing their production. In the last part of the chapter, we highlight the potential interactions between Bacillus spp. and other soil microorganisms in developing consortia of biocontrol agents combining species with synergistic activities for plant health improvement.


Author(s):  
Praveen Kumar

Nanoparticles are widely used in the agricultural sector because of their distinctive properties. Studies have shown the influence of nanoparticles on plant growth and production. Nanoparticles act as effective carriers in the delivery of agrochemicals to plants. They provide site targeted delivery of nutrients and thus, prevents wastage of nutrients applied for plant growth and productivity. Bioremediation of pollutants is an emerging technology that provides bio-nano materials for the protection of agriculture from pollution. The aim of this review is to present and focus on the latest techniques used for the reduction of environmental pollution and improved agricultural production. This review speculates about the biosynthesis of nanomaterials from different sources like plants, fungi, and bacteria along with chemical and organic synthesis from carbon, silver, and gold. The role of nanoscience in detecting plant diseases and the removal of heavy metals. Application of Nanoscience in storing, production, processing, and transport of agricultural materials. It is also emphasized that Nanoscience may transform agriculture through the innovation of new techniques like Precision farming, improvement of plants to engross nutrients, targeted use of inputs, detection and control of diseases and withstand environmental pressures. Further, efforts have been made in describing that nanoparticles may act as a better substitute for agricultural plant growth and nutrition improvement by lowering the content of pollutants and pre-detection of diseases in plants. The biosynthetic route of nanomaterial synthesis could emerge as a better and safer option for environmental pollution reduction. Thus, nanoscience may increase agricultural production to feed a huge population in near future.


Author(s):  
David Vogel

This book examines the politics of consumer and environmental risk regulation in the United States and Europe over the last five decades, explaining why America and Europe have often regulated a wide range of similar risks differently. It finds that between 1960 and 1990, American health, safety, and environmental regulations were more stringent, risk averse, comprehensive, and innovative than those adopted in Europe. But since around 1990 global regulatory leadership has shifted to Europe. What explains this striking reversal? This book takes an in-depth, comparative look at European and American policies toward a range of consumer and environmental risks, including vehicle air pollution, ozone depletion, climate change, beef and milk hormones, genetically modified agriculture, antibiotics in animal feed, pesticides, cosmetic safety, and hazardous substances in electronic products. The book traces how concerns over such risks—and pressure on political leaders to do something about them—have risen among the European public but declined among Americans. The book explores how policymakers in Europe have grown supportive of more stringent regulations while those in the United States have become sharply polarized along partisan lines. And as European policymakers have grown more willing to regulate risks on precautionary grounds, increasingly skeptical American policymakers have called for higher levels of scientific certainty before imposing additional regulatory controls on business.


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