Endophytic fungi as biocontrol agents: elucidating mechanisms in disease suppression (original) (raw)

Role of Endophytic Fungi in Plant Disease Management

vignan varta, 2023

The majority of plant diseases are caused by microorganisms of which fungi are the most common followed by bacteria and viruses. Endophytic fungi reside in the tissues beneath the epidermal cell layers and live within a plant for at least part of its life without causing apparent diseases. An alternative for chemical control is the application of biocontrol agents, which includes the application of fungal endophytes in the biocontrol of a wide array of plant pathogens. Endophytes' ability to successfully colonize a host plant depends on several variables, including the plant's tissue type, genotype, microbial taxon and strain type, and biotic and abiotic environmental conditions. Crops with endophyte colonization have a higher propensity to withstand diverse stresses than those without this relationship. Through antibiosis or induced systemic resistance, endophytes are crucial for maintaining the health of plants since they can shield or prepare the plant for biotic challenges while also promoting growth and productivity. The primary filamentous fungi investigated and employed as biological control agents against nematodes as resistance inducers are endophytic fungi. Overall, endophytes are viewed as extremely significant plant partners with the ability to increase agricultural output by reducing yield loss through the provision of better stress tolerance to the host in a sustainable manner.

Endophytic Fungi: Biological Control and Induced Resistance to Phytopathogens and Abiotic Stresses

Pathogens, 2021

Plant diseases cause losses of approximately 16% globally. Thus, management measures must be implemented to mitigate losses and guarantee food production. In addition to traditional management measures, induced resistance and biological control have gained ground in agriculture due to their enormous potential. Endophytic fungi internally colonize plant tissues and have the potential to act as control agents, such as biological agents or elicitors in the process of induced resistance and in attenuating abiotic stresses. In this review, we list the mode of action of this group of microorganisms which can act in controlling plant diseases and describe several examples in which endophytes were able to reduce the damage caused by pathogens and adverse conditions. This is due to their arsenal of molecules generated during the interaction by which they form a kind of biological shield in the plant. Furthermore, considering that endophytic fungi can be an important tool in managing for biot...

Fungal Endophytes and Their Role in Agricultural Plant Protection against Pests and Pathogens

Plants, 2022

Virtually all examined plant species harbour fungal endophytes which asymptomatically infect or colonize living plant tissues, including leaves, branches, stems and roots. Endophyte-host interactions are complex and span the mutualist–pathogen continuum. Notably, mutualist endophytes can confer increased fitness to their host plants compared with uncolonized plants, which has attracted interest in their potential application in integrated plant health management strategies. In this review, we report on the many benefits that fungal endophytes provide to agricultural plants against common non-insect pests such as fungi, bacteria, nematodes, viruses, and mites. We report endophytic modes of action against the aforementioned pests and describe why this broad group of fungi is vitally important to current and future agricultural practices. We also list an extensive number of plant-friendly endophytes and detail where they are most commonly found or applied in different studies. This rev...

Searching for Novel Fungal Biological Control Agents for Plant Disease Control Among Endophytes

Endophytes for a Growing World, 2019

There are increasing efforts aiming to utilise endophytes as biological control agents (BCAs) to improve crop production. However, reliability remains a major practical constraint for the development of novel BCAs. Many organisms are adapted to their specific habitat; it is optimistic to expect that a new organism added can find a niche or even out-compete those adapted and already present. Our approach for isolating novel BCAs for specific plant diseases is therefore to look in healthy plants in a habitat where disease is a problem, since we predict that it is more likely to find competitive strains among those present and adapted. In vitro inhibitory activities often do not correlate with in planta efficacy, especially since endophytes rely on intimate plant contact. They can, however, be useful to indicate modes of action. We therefore screen for in planta biological activity as early as possible in the process in order to minimise the risk of discarding valuable strains. Finally, some fungi are endophytic in one situation and pathogenic in another (the mutualism-parasitism continuum). This depends on their biology, environmental conditions, the formulation of inoculum, the health, developmental stage and cultivar of the host plant, and the structure of the plant microbiome .

Fungal Endophytes and their Role in Plant Protection

Current Organic Chemistry, 2007

Endophytes (fungal and bacterial organisms) have attracted great interest over the past few years because their presence benefits the host plant (development and defence) and they are a source of secondary metabolites of potential interest and thus play an important role in the regulation of plant communities and their herbivores. There are an increasing number of reports on their identification and on the production of secondary metabolites. Their role in plant-pathogen and plant-insect interactions is receiving increasing attention because of their potential use in pest control, however, little is known about their physiology and the regulation processes of the plant-endophyte interaction. N o t F o r D i s t r i b u t i o n 708

Role of fungal endophytes in plant protection

Management of fungal plant pathogens, 2010

Endophytes are the microorganisms that reside inside healthy plant tissues without causing any detectable disease symptoms to the host. Often, each and every plant harbours either one or a battery of endophytic microorganisms. The study of endophytes is now on a voyage of interest, not only because of their role in fi lling the divide between discovered and undiscovered microbial diversity, but also due to their harbouring a great potential to produce novel natural products. Other than soil, higher plants also act as an alternative resource to isolate potential microorganisms. Natural compounds ranging from crop protection to human welfare have been isolated from this alternative source of endophytes. Several anticancer, antibiotic, antimycotic, antiviral, antioxidant, nematicide, insecticide and immunosuppressive compounds have been reported from endophytes, such as cytochalasines, ambuic acid, oocydin, jesterone, cryptocandin, lolitrem B, and 3-hydroxypropionic acid and taxol, etc. Many of them produce some toxic alkaloids and protect their hosts from herbivores. They also improve the growth and yield of crops under various stressed conditions. Endophytic fungi have been emerging as a new tool in genetic engineering, the pharmaceutical industry and in crop protection as well. In this chapter, the ability and role of endophytic fungi to ward off pests and environmental stresses on plants is discussed. Sr. No.

Endophyte-host interactions. I. Plant defense reactions to endophytic and pathogenic fungi

Symbiosis, 1998

To study the nature of the endophyte-host relationship, endophytes and pathogens were isolated from healthy and diseased plant tissue of Lamium purpureum and tested for their potential aggressiveness. The plant defense reactions to the endophytes and pathogens which were selected on the basis of this aggressiveness were compared using three test systems: dual cultures of intact plants and fungi, dual cultures of plant calli and fungi, and suspension cultures. In dual cultures in which there was no direct contact between fungus and callus or plant, the activity of phenylalanine ammonia-lyase (PAL) was stimulated more both in dual cultures of intact plants and of plant calli with the pathogen than with the endophytic fungi. In contrast, in suspension cultures, PAL-activity, the accumulation of phenols and the production of H202 was greater when elicited with endophytic mycelium and elicitor than with those of a pathogen. The different responses in the test systems and the apparently d...

The fungal endophyte–plant interactions: Scope in sustainable agriculture

Novel Microorganisms for Plant Growth PromotionPublisher: Darshan Publishers, Tamil Nadu, India, 2021

The term ‘endophyte’ was proposed by De Bary (1866) for the organisms that remain present inside plant tissues without causing any disease symptoms. Several species of bacterial, fungal and viral endophytes are known to colonize plant tissues. Their presence is considered ubiquitous in the plant kingdom. However, the endophyte-plant association is complex and not fully understood. Fungi are the predominant members of the endophytic community. Being filamentous, fungal endophytes (FEs) more intensively impact plant growth and metabolism. Endophyte fungi live at least some part of their life cycle inside plant tissues. Millions of different fungal species are surviving on earth, most of which have not been identified. These fungi may be common saprophytes, animal or human pathogens, phytopathogens, endophytes or mycorrhizal. Contrary to mycorrhizal fungi, the FEs grow inside plant tissues. Most of the time, such associations are symbiotic. Most endophytes enter the plant system through foliage, roots, stems and bark and could also horizontally transmit through spores, forming a ‘constitutive’ or ‘inducible’ endopohytism. The former involves endophyte-infected plants that transfer the infection vertically via seeds. The latter includes several other fungi that colonize host tissues. The roots of more than 90% of flowering plants harbor the largest pool of FEs in the plant body.

Fungal Endophyte-Mediated Crop Improvement: The Way Ahead

Frontiers in Plant Science, 2020

Endophytes are non-disease causing microbes (bacteria and fungi) surviving in living tissues of plants. Their intimate association and possible coevolution with their plant partners have resulted in them contributing to an array of plant growth benefits ranging from enhanced growth and biomass accumulation, tolerance to abiotic and biotic stresses and in nutrient acquisition. The last couple of decades have witnessed a burgeoning literature on the role of endophytes (Class 3 type) in regulating plant growth and development and their adaptation to abiotic and biotic stresses. Though the underlying mechanisms of plant-endophyte interactions are far from clear, several studies have raised the hope of their potential application in agriculture, especially in mitigating abiotic and biotic stresses. The use of endophytes is envisaged as a route to reduce the production cost and burden on the environment by lessening the dependence on breeding for crop improvement and agrochemicals. Unfortunately, save a few well documented examples of their use, a little of these insights has been translated into actual agricultural applications. Here, we reflect on this paucity and elaborate on some of the important bottlenecks that might stand in way of fully realizing the potential that endophytes hold for crop improvement. We stress the need to study various facets of the endophyte-plant association for their gainful application in agriculture.