Advances in screening approaches for the development of microbial bioprotectants to control plant diseases

2021 ◽  
pp. 33-86
Author(s):  
Wagner Bettiol ◽  
◽  
Flávio Henrique Vasconcelos de Medeiros ◽  
Josiane Barros Chiaramonte ◽  
Rodrigo Mendes ◽  
...  

The success of a biological control programme depends on the isolation and selection of antagonists. There is an enormous diversity of culturable microbial species in the soil, rhizosphere, phylloplane, spermosphere and carposphere, which can be used in the isolation and selection of antagonists. The structures of fungal plant pathogens concerned with survival and infection may also be sources of antagonists. Although non-culturable microorganisms and microbiome-based strategies have great potential for development as commercial products in disease control, more knowledge is needed to understand the mechanisms involved in interactions between plants and complex microbial communities. Methods of isolation and selection of the most commercially exploited groups of antagonists and their advantages and disadvantages are discussed in this chapter as well as those of non-traditional antagonists. Finally, possible strategies for engineering the soil and host microbiome to actively promote plant protection against pathogens are discussed.

Toxins ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 701 ◽  
Author(s):  
Sabrina Sarrocco ◽  
Antonio Mauro ◽  
Paola Battilani

Among plant fungal diseases, those affecting cereals represent a huge problem in terms of food security and safety. Cereals, such as maize and wheat, are very often targets of mycotoxigenic fungi. The limited availability of chemical plant protection products and physical methods to control mycotoxigenic fungi and to reduce food and feed mycotoxin contamination fosters alternative approaches, such as the use of beneficial fungi as an active ingredient of biological control products. Competitive interactions, including both exploitation and interference competition, between pathogenic and beneficial fungi, are generally recognized as mechanisms to control plant pathogens populations and to manage plant diseases. In the present review, two examples concerning the use of competitive beneficial filamentous fungi for the management of cereal diseases are discussed. The authors retrace the history of the well-established use of non-aflatoxigenic isolates of Aspergillus flavus to prevent aflatoxin contamination in maize and give an overview of the potential use of competitive beneficial filamentous fungi to manage Fusarium Head Blight on wheat and mitigate fusaria toxin contamination. Although important steps have been made towards the development of microorganisms as active ingredients of plant protection products, a reasoned revision of the registration rules is needed to significantly reduce the chemical based plant protection products in agriculture.


2021 ◽  
pp. 103-122
Author(s):  
Marc Bardin ◽  
◽  
Thomas Pressecq ◽  
Philippe C. Nicot ◽  
Yousra Bouaoud ◽  
...  

Plant pathogens can develop resistance to conventional plant protection products but their ability to overcome the effect of microbial bioprotectants is still poorly known. However, various studies show that susceptibility of plant pathogens to microbial bioprotectants can be highly variable. This may contribute to the inconsistent efficacy of microbial bioprotectants sometimes observed in the field. An important question is whether the widespread use of microbial bioprotectants in the field could conduct to the selection of even more resistant phenotypes of plant pathogens. This chapter highlights current knowledge concerning erosion of microbial bioprotectants against plant pathogens and its possible consequences for field efficacy.


2018 ◽  
Author(s):  
L. Bousset ◽  
M. Ermel ◽  
B. Soglonou ◽  
O. Husson

AbstractFungal plant pathogens live in the specific environment of plants. Understanding of the interaction between pathogens and their host plants might open new ways to control plant diseases. Yet, the specificities of the plant environment and its effects on fungal growth are not yet fully explored. Both pH and Eh play a key role during the interaction between the fungus and its host plants, but often studied independently or at different scales. To decipher the interrelation between plant growth and their soil environment, recent theoretical and methodological advances have been made through the joint characterization of the pH and Eh. This opens the prospect to develop similar methods for fungi. The aim of our study was to investigate whether the methods developed for soil could be transposed to fungi. We first worked on artificial media, assessing the impact of fungal growth on the media in cultures. The growth of all 16 species tested significantly altered either Eh, pH or both in agar media. Measuring Eh reveals that even the species not modifying pH can have an impact on the surrounding environment. Reciprocally, altered media were used to characterize sensitivity of fungal growth to both pH and Eh parameters. The response of the six fungi tested to the modified media was quantitative with a decrease in colony diameter. In addition, colony aspect was repeatedly and thoroughly modified. As a first step towards the same studies in conditions matching the natural environment of fungal pathogens, we tested how the measurement can be performed with fungi growing on oilseed rape plants. In infected plant stems, pH and Eh were significantly altered, in opposite directions for L. maculans and S. sclerotiorum. The observed alcalinisation or acidification correlates with canker length. Our series of experiments indicate that the procedure published for Eh and pH in soil can be extended for measurement in agar media and in infected plants. Further, the joint characterization of both parameters opens the way to a more precise understanding of the impact of fungi on their environment, and conversely, of the environment on fungal growth. The availability of methods for measurement opens the prospect to study combinations of stresses, either on agar media or in plants, and get an understanding of the involvement of pH and Eh modifications in these interactions.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marta Matuszewska ◽  
Tomasz Maciąg ◽  
Magdalena Rajewska ◽  
Aldona Wierzbicka ◽  
Sylwia Jafra

AbstractPseudomonas donghuensis P482 is a tomato rhizosphere isolate with the ability to inhibit growth of bacterial and fungal plant pathogens. Herein, we analysed the impact of the carbon source on the antibacterial activity of P482 and expression of the selected genes of three genomic regions in the P482 genome. These regions are involved in the synthesis of pyoverdine, 7-hydroxytropolone (7-HT) and an unknown compound (“cluster 17”) and are responsible for the antimicrobial activity of P482. We showed that the P482 mutants, defective in these regions, show variations and contrasting patterns of growth inhibition of the target pathogen under given nutritional conditions (with glucose or glycerol as a carbon source). We also selected and validated the reference genes for gene expression studies in P. donghuensis P482. Amongst ten candidate genes, we found gyrB, rpoD and mrdA the most stably expressed. Using selected reference genes in RT-qPCR, we assessed the expression of the genes of interest under minimal medium conditions with glucose or glycerol as carbon sources. Glycerol was shown to negatively affect the expression of genes necessary for 7-HT synthesis. The significance of this finding in the light of the role of nutrient (carbon) availability in biological plant protection is discussed.


Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2393
Author(s):  
Xiuping Wang ◽  
Fei Peng ◽  
Caihong Cheng ◽  
Lina Chen ◽  
Xuejuan Shi ◽  
...  

Plant pathogens constantly develop resistance to antimicrobial agents, and this poses great challenges to plant protection. Therefore, there is a pressing need to search for new antimicrobials. The combined use of antimicrobial agents with different antifungal mechanisms has been recognized as a promising approach to manage plant diseases. Graphene oxide (GO) is a newly emerging and highly promising antimicrobial agent against various plant pathogens in agricultural science. In this study, the inhibitory activity of GO combined with fungicides (Mancozeb, Cyproconazol and Difenoconazole) against Fusarium graminearum was investigated in vivo and in vitro. The results revealed that the combination of GO and fungicides has significant synergistic inhibitory effects on the mycelial growth, mycelial biomass and spore germination of F. graminearum relative to single fungicides. The magnitude of synergy was found to depend on the ratio of GO and fungicide in the composite. In field tests, GO–fungicides could significantly reduce the disease incidence and disease severity, exhibiting a significantly improved control efficacy on F. graminearum. The strong synergistic activity of GO with existing fungicides demonstrates the great application potential of GO in pest management.


2018 ◽  
Vol 56 (1) ◽  
pp. 581-610 ◽  
Author(s):  
Cristina Rosa ◽  
Yen-Wen Kuo ◽  
Hada Wuriyanghan ◽  
Bryce W. Falk

The origin of RNA interference (RNAi), the cell sentinel system widely shared among eukaryotes that recognizes RNAs and specifically degrades or prevents their translation in cells, is suggested to predate the last eukaryote common ancestor ( 138 ). Of particular relevance to plant pathology is that in plants, but also in some fungi, insects, and lower eukaryotes, RNAi is a primary and effective antiviral defense, and recent studies have revealed that small RNAs (sRNAs) involved in RNAi play important roles in other plant diseases, including those caused by cellular plant pathogens. Because of this, and because RNAi can be manipulated to interfere with the expression of endogenous genes in an intra- or interspecific manner, RNAi has been used as a tool in studies of gene function but also for plant protection. Here, we review the discovery of RNAi, canonical mechanisms, experimental and translational applications, and new RNA-based technologies of importance to plant pathology.


2021 ◽  
pp. 429-472
Author(s):  
Dan Funck Jensen ◽  
◽  
Mukesh Dubey ◽  
Birgit Jensen ◽  
Magnus Karlsson ◽  
...  

The fungus Clonostachys rosea was recognized as an aggressive parasite on other fungi already in the late 1950s. Research into its potential use in biological control of plant diseases soon followed. Today, there are several commercial products based on C. rosea available for biocontrol applications worldwide. Although its mycoparasitic ability has attracted a lot of interest, C. rosea is now viewed as an ecological generalist whose lifestyle also includes plant endophytism, rhizosphere competence and polyphagous ability. Protocols for producing high amounts of C. rosea spores are available for both solid state and liquid fermentation. Low temperature and low moisture content are key factors that influence the shelf life of C. rosea propagules. Products based on C. rosea can be delivered to flowers using bumble bees, applied by spraying or as seed dressing or by incorporation into the soil. Clonostachys rosea is today an established factor in sustainable plant protection strategies.


Author(s):  
Deepti Malviya ◽  
Pramod Kumar Sahu ◽  
Udai B. Singh ◽  
Surinder Paul ◽  
Amrita Gupta ◽  
...  

Microorganisms area treasure in terms of theproduction of various bioactive compounds which are being explored in different arenas of applied sciences. In agriculture, microbes and their bioactive compounds are being utilized in growth promotion and health promotion withnutrient fortification and its acquisition. Exhaustive explorations are unraveling the vast diversity of microbialcompounds with their potential usage in solving multiferous problems incrop production. Lipopeptides are one of such microbial compounds which havestrong antimicrobial properties against different plant pathogens. These compounds are reported to be produced by bacteria, cyanobacteria, fungi, and few other microorganisms; however, genus Bacillus alone produces a majority of diverse lipopeptides. Lipopeptides are low molecular weight compounds which havemultiple industrial roles apart from being usedas biosurfactants and antimicrobials. In plant protection, lipopeptides have wide prospects owing totheirpore-forming ability in pathogens, siderophore activity, biofilm inhibition, and dislodging activity, preventing colonization bypathogens, antiviral activity, etc. Microbes with lipopeptides that haveall these actions are good biocontrol agents. Exploring these antimicrobial compounds could widen the vistasof biological pest control for existing and emerging plant pathogens. The broader diversity and strong antimicrobial behavior of lipopeptides could be a boon for dealing withcomplex pathosystems and controlling diseases of greater economic importance. Understanding which and how these compounds modulate the synthesis and production of defense-related biomolecules in the plants is a key question—the answer of whichneeds in-depth investigation. The present reviewprovides a comprehensive picture of important lipopeptides produced by plant microbiome, their isolation, characterization, mechanisms of disease control, behavior against phytopathogens to understand different aspects of antagonism, and potential prospects for future explorations as antimicrobial agents. Understanding and exploring the antimicrobial lipopeptides from bacteria and fungi could also open upan entire new arena of biopesticides for effective control of devastating plant diseases.


2005 ◽  
Vol 82 (3) ◽  
pp. 85-102 ◽  
Author(s):  
C.L. Doumbou ◽  
M.K. Hamby Salove ◽  
D.L. Crawford ◽  
C. Beaulieu

Actinomycetes represent a high proportion of the soil microbial biomass and have the capacity to produce a wide variety of antibiotics and of extracellular enzymes. Several strains of actinomycetes have been found to protect plants against plant diseases. This review focuses on the potential of actinomycetes as (a) source of agroactive compounds, (b) plant growth promoting organisms, and (c) biocontrol tools of plant diseases. This review also addresses examples of biological control of fungal and bacterial plant pathogens by actinomycetes species which have already reached the market or are likely to be exploited commercially within the next few years.


2017 ◽  
Vol 17 (1) ◽  
pp. 31-35
Author(s):  
B Oyuntogtokh ◽  
M Byambasuren

At present, plant diseases caused by soil borne plant pathogens have major constraints on crop production. Which include genera Fusarium spp, Phytophtora spp, Sclerotinia and Altenaria. Due to this reason, chemical fungicides are routinely used to control plant disease, which is also true in Mongolian case. However, use of these chemicals has caused various problems including environmental pollution with consequence of toxicity to human health also resistance of some pathogens to these fungicides are present. Fortunately, an alternative method to reduce the effect of these plant pathogens is the use of antagonist microorganisms. Therefore, some species of the genus Bacillus are recognized as one of the most effective biological control agent.Our research was focused to isolate Bacillus licheniformis, with antifungal potential, from indigenous sources. In the current study, 28 bacterial cultures were isolated from soil and fermented mare’s milk also named as koumiss. Isolated bacterial cultures were identified according to simplified key for the tentative identification of typical strain of Bacillus species. As a result 8 strains were positive and further screened for antifungal activity against Fusarium spp and Alternaria solani. Out of these 8 strains 5 strains are selected based on their high effectiveness against fungal pathogens and for further confirmation Polymerase Chain reaction run for effective bacterial strains using specific primers B.Lich-f and B.Lich-r. 


Sign in / Sign up

Export Citation Format

Share Document