Radiotolerant endophytic bacteria and analysis of the effects of 137Cesium on the metabolome of Pantoea sp

Some bacteria have developed mechanisms to withstand the stress caused by ionizing radiation. The ability of these radioresistant microorganisms to survive high levels of radiation is primarily attributed to their DNA repair mechanisms and the production of protective metabolites. To determine the effect of irradiation on bacterial growth, we propose to compare the metabolites produced by the irradiated isolates to those of the control (non-irradiated isolates) using mass spectrometry, molecular networking, and chemometric analysis. We identified the secondary metabolites produced by these bacteria and observed variations in growth following irradiation. Notably, after 48 h of exposure to radiation, Pantoea sp. bacterial cells exhibited a significant 6-log increase compared to non-irradiated cells. Non-irradiated cells produce exclusively Pyridindolol, 1-hydroxy-4-methylcarbostyril, N-alkyl, and N-2-alkoxyethyl diethanolamine, while 5'-methylthioadenosine was detected only in irradiated cells. These findings suggest that the metabolic profile of Pantoea sp. remained relatively stable. The results obtained from this study have the potential to facilitate the development of innovative strategies for harnessing the capabilities of endophytic bacteria in radiological protection and bioremediation of radionuclides.

Harnessing fungal endophytes for natural management: a biocontrol perspective

In the ever-evolving realm of agriculture, the convoluted interaction between plants and microorganisms have assumed paramount significance. Fungal endophytes, once perceived as mere bystanders within plant tissues, have now emerged as dynamic defenders of plant health. This comprehensive review delves into the captivating world of fungal endophytes and their multifaceted biocontrol mechanisms. Exploring their unique ability to coexist with their plant hosts, fungal endophytes have unlocked a treasure trove of biological weaponry to fend off pathogens and enhance plant resilience. From the synthesis of bioactive secondary metabolites to intricate signaling pathways these silent allies are masters of biological warfare. The world of fungal endophytes is quite fascinating as they engage in a delicate dance with the plant immune system, orchestrating a symphony of defense that challenges traditional notions of plant-pathogen interactions. The journey through the various mechanisms employed by these enigmatic endophytes to combat diseases, will lead to revelational understanding of sustainable agriculture. The review delves into cutting-edge research and promising prospects, shedding light on how fungal endophytes hold the key to biocontrol and the reduction of chemical inputs in agriculture. Their ecological significance, potential for bioprospecting and avenues for future research are also explored. This exploration of the biocontrol mechanisms of fungal endophytes promise not only to enrich our comprehension of plant-microbe relationships but also, to shape the future of sustainable and ecofriendly agricultural practices. In this intricate web of life, fungal endophytes are indeed the unsung heroes, silently guarding our crops and illuminating a path towards a greener, healthier tomorrow.

Endophytic Diaporthe as Promising Leads for the Development of Biopesticides and Biofertilizers for a Sustainable Agriculture

Plant pathogens are responsible for causing economic and production losses in several crops worldwide, thus reducing the quality and quantity of agricultural supplies. To reduce the usage of chemically synthesized pesticides, strategies and approaches using microorganisms are being used in plant disease management. Most of the studies concerning plant-growth promotion and biological agents to control plant diseases are mainly focused on bacteria. In addition, a great portion of registered and commercialized biopesticides are bacterial-based products. Despite fungal endophytes having been identified as promising candidates for their use in biological control, it is of the utmost importance to develop and improve the existing knowledge on this research field. The genus Diaporthe, encompasses plant pathogens, saprobes and endophytes that have been screened for secondary metabolite, mainly due to their production of polyketides and a variety of unique bioactive metabolites with agronomic importance. Some of these metabolites exhibit antifungal and antibacterial activity for controlling plant pathogens, and phytotoxic activity for the development of potential mycoherbicides. Moreover, species of Diaporthe are reported as promising agents in the development of biofertilizers. For this reason, in this review we summarize the potential of Diaporthe species to produce natural products with application in agriculture and describe the benefits of these fungi to promote their host plant's growth.

Plant associated endophytic fungi as potential bio-factories for extracellular enzymes: Progress, Challenges and Strain improvement with precision approaches

There is an intricate network of relations between endophytic fungi and their hosts that affects the production of various bioactive compounds. Plant-associated endophytic contain industrially important enzymes and have the potential to fulfill their rapid demand in the international market to boost business in technology. Being safe and metabolically active, they have replaced the usage of toxic and harmful chemicals and hold a credible application in biotransformation, bioremediation, and industrial processes. Despite these, there are limited reports on fungal endophytes that can directly cater to the demand and supply of industrially stable enzymes. The underlying reasons include low endogenous production and secretion of enzymes from fungal endophytes which have raised concern for widely accepted applications. Hence it is imperative to augment the biosynthetic and secretory potential of fungal endophytes. Modern state-of-the-art biotechnological technologies aiming at strain improvement using cell factory engineering as well as precise gene editing like Clustered Regularly Interspaced Palindromic Repeats (CRISPR) and its Associated proteins (Cas) systems which can provide a boost in fungal endophyte enzyme production. Additionally, it is vital to characterize optimum conditions to grow one strain with multiple enzymes (OSME). The present review encompasses various plants-derived endophytic fungal enzymes and their applications in various sectors. Further, we postulate the feasibility of new precision approaches with an aim for strain improvement and enhanced enzyme production.

Marine endophytic fungal metabolites: A whole new world of pharmaceutical therapy exploration

The growing threat arises due to diseases such as cancer and the infections around the world leading to a critical requirement for novel and constructive compounds with unique ways of action capable of combating these deadly diseases. At present, it is evident that endophytic fungi constitute an enormous as well as comparatively untapped source of great biodiversity that can be considered as a wellspring of effective novel natural products for medical, agricultural and industrial use. Marine endophytic fungi have been found in every marine plants (algae, seagrass, driftwood, mangrove plants), marine vertebrates (mainly, fish) or marine invertebrates (mainly, sponge and coral) inter- and intra-cellular without causing any palpable symptoms of illness. Since evolution of microbes and eukaryotes to a higher level, coevolution has resulted in specific interaction mechanisms. Endophytic fungi are known to influence the life cycle and are necessary for the homeostasis of their eukaryotic hosts and the chemical signals of their host have been shown to activate gene expression in endophytes to induce expression of endophytic secondary metabolites. Marine endophytic fungi are receiving increasing attention by chemists because of their varied and structurally unmatched compounds that have strong biological roles in life as lead pharmaceutical compounds, including anticancer, antiviral, insulin mimetic, antineurodegenerative, antimicrobial, antioxidant and immuno-suppressant compounds. Moreover, fungal endophytes proved to have different biological activities for exploitation in the environmental and agricultural sustainability.

Molecular Phylogeny of Endophytic Fungi from Rattan (Calamus castaneus Griff.) Spines and Their Antagonistic Activities against Plant Pathogenic Fungi

Calamus castaneus is a common rattan palm species in the tropical forests of Peninsular Malaysia and is noticeable by the yellow-based spines that cover the stems. This study aimed to determine the prevalence of fungal endophytes within C. castaneus spines and whether they inhibit the growth of fungal pathogens. Twenty-one genera with 40 species of fungal endophytes were isolated and identified from rattan palm spines. Based on molecular identification, the most common isolates recovered from the spines were Colletotrichum (n = 19) and Diaporthe spp. (n = 18), followed by Phyllosticta spp., Xylaria sp., Trichoderma spp., Helminthosporium spp., Penicillium spp., Fusarium spp., Neopestalotiopsis spp., Arthrinium sp., Cyphellophora sp., Cladosporium spp., Curvularia sp., Bionectria sp., and Acremonium spp. Non-sporulating fungi were also identified, namely Nemania primolutea, Pidoplitchkoviella terricola, Muyocopron laterale, Acrocalymma fici, Acrocalymma medicaginis, and Endomelanconiopsis endophytica. The isolation of these endophytes showed that the spines harbor endophytic fungi. Most of the fungal endophytes inhibited the growth of several plant pathogenic fungi, with 68% of the interactions resulting in mutual inhibition, producing a clear inhibition zone of <2 mm. Our findings demonstrate the potential of the fungal endophytes from C. castaneus spines as biocontrol agents.