Characterization of the Biosynthetic Gene Cluster for the Ribosomally Synthesized Cyclic Peptide Epichloëcyclins in .

The various grass-induced epichloëcyclins of the spp. are ribosomally synthesized and post-translationally modified peptides (RiPPs), produced as small, secreted cyclopeptides from a single gene, Here, four clustered and coregulated genes (, , , and ) with predicted roles in epichloëcyclin production in were evaluated through gene disruption. Subsequent chemical analysis indicates that GigB is a DUF3328 domain-containing protein associated with cyclization of epichloëcyclins; GigC is a methyltransferase enzyme responsible for N-methylation of desmethylepichloëcyclins; and KexB is a subtilisin-like enzyme, partly responsible for the propeptide cleavage of epichloëcyclin intermediates.

High-affinity iron uptake is required for optimal Epichloë festucae colonization of Lolium perenne and seed transmission.

Epichloë festucae uses a siderophore-mediated system to acquire iron, which is important to maintain endophyte-grass symbioses. Here we investigate the roles of the alternative iron acquisition system, reductive iron assimilation (RIA), via disruption of the fetC gene, which encodes a multicopper ferroxidase, either alone (i.e.

Survey of the Endophytic Bacteria Inhabiting Wild Seed Using 16S rRNA Gene Amplicon Sequencing.

We report a preliminary survey of the endophytic bacterial microbiota of seed from wild carrot (Daucus carota) using 16S rRNA gene amplicon sequencing. , , , and were the most abundant phyla detected, while , , , , Pseudomonas, , , and were the most abundant genera.

Dissection of the epoxyjanthitrem pathway in sp. TG-3 strain AR37 by CRISPR gene editing.

var. and sp. TG-3 are filamentous fungal endophytes of perennial ryegrass () that have a substantial impact on New Zealand's agricultural economy by conferring biotic advantages to the host grass.

Identification of Genetic Diversity, Pyrrocidine-Producing Strains and Transmission Modes of Endophytic Fungi from Crops.

Genotyping by sequencing (GBS) was used to reveal the inherent genetic variation within the haploid fungi isolated from diverse germplasm, including modern and its wild progenitors-the teosintes. In accordance with broad host relationship parameters, GBS analysis revealed significant host lineages of genetic diversity, indicating that genetic variation may associate with different evolutionary histories of host species or varieties. Based on a recently identified PKS-NRPS gene responsible for pyrrocidine biosynthesis in fungi, a novel PCR assay was developed to discriminate pyrrocidine-producing strains.

Factors controlling the effects of mutualistic bacteria on plants associated with fungi.

Plants interacting with mutualistic fungi (MF) or antagonistic fungi (AF) can form associations with bacteria. We assessed whether the performance gain conferred by mutualistic bacteria to fungal-associated plants is affected by the interaction between symbiont traits, type of bacterial-protective traits against AF and abiotic/biotic stresses. Results showed that (A) performance gain conferred by bacteria to MF-associated plants was greater when symbionts promoted distinct rather than similar plant functions, (B) bacterial-based alleviation of the AF's negative effect on plants was independent of the type of protective trait, (C) bacteria promoted a greater performance of symbiotic plants in presence of biotic, but not abiotic, stress compared to stress-free situations.

Soil Nitrogen Treatment Alters Microbiome Networks Across Farm Niches.

Agriculture is fundamental for food production, and microbiomes support agriculture through multiple essential ecosystem services. Despite the importance of individual (i.e.

Cross-species transcriptomics identifies core regulatory changes differentiating the asymptomatic asexual and virulent sexual life cycles of grass-symbiotic Epichloë fungi.

Fungi from the genus Epichloë form systemic endobiotic infections of cool season grasses, producing a range of host-protective natural products in return for access to nutrients. These infections are asymptomatic during vegetative host growth, with associations between asexual Epichloë spp. and their hosts considered mutualistic.

CRISPR-Cas9 gene editing and rapid detection of gene-edited mutants using high-resolution melting in the apple scab fungus, Venturia inaequalis.

Apple scab, caused by the fungal pathogen Venturia inaequalis, is the most economically important disease of apple (Malus x domestica) worldwide. To develop durable control strategies against this disease, a better understanding of the genetic mechanisms underlying the growth, reproduction, virulence and pathogenicity of V. inaequalis is required.

Regulation of host-infection ability in the grass-symbiotic fungus Epichloë festucae by histone H3K9 and H3K36 methyltransferases.

Recent studies have identified key genes that control the symbiotic interaction between Epichloë festucae and Lolium perenne. Here we report on the identification of specific E. festucae genes that control host infection.

Fungal Endophytes-From a Biological Curiosity in Wild Grasses to an Essential Component of Resilient High Performing Ryegrass and Fescue Pastures.

The relationship between endophytes found in a wide range of temperate grasses spans the continuum from antagonistic to mutualistic. The diversity of asexual mutualistic types can be characterised by the types of alkaloids they produce in planta. Some of these are responsible for detrimental health and welfare issues of ruminants when consumed, while others protect the host plant from insect pests and pathogens.

Complete Genome Sequence of sp. Strain E222, a Bacterial Symbiont of an Fungal Endophyte of Ryegrass.

We report on the whole-genome sequence of sp. strain E222, a bacterium isolated from a fresh culture of var. , a mutualistic fungal endophyte of perennial ryegrass.

Draft Genome Sequence of Simplicillium aogashimaense 72-15.1, a Putative Endophyte of Brachiaria brizantha.

Here, we report a 29-Mb draft genome sequence of strain 72-15.1 of (Cordycipitaceae, Hypocreales). Strain 72-15.

Symbiotic bacteria of plant-associated fungi: friends or foes?

Many bacteria form symbiotic associations with plant-associated fungi. The effects of these symbionts on host fitness usually depend on symbiont or host genotypes and environmental conditions. However, bacterial endosymbionts, that is those living within fungal cells, may positively regulate host performance as their survival is often heavily dependent on host fitness.

Regulation of subtelomeric fungal secondary metabolite genes by H3K4me3 regulators CclA and KdmB.

Studies on the regulation of fungal secondary metabolism highlight the importance of histone H3K4 methylation regulators Set1, CclA (Ash2) and KdmB (KDM5), but it remains unclear whether these proteins act by direct modulation of H3K4me3 at the target genes. In filamentous fungi, secondary metabolite genes are frequently located near telomeres, a site where H3K4 methylation is thought to have a repressive role. Here we analyzed the role of CclA, KdmB and H3K4me3 in regulating the subtelomeric EAS and LTM cluster genes in Epichloë festucae.

The Role of SreA-Mediated Iron Regulation in Maintaining - Symbioses.

In ascomycetes and basidiomycetes, iron-responsive GATA-type transcriptional repressors are involved in regulating iron homeostasis, notably to prevent iron toxicity through control of iron uptake. To date, it has been unknown whether this iron regulator contributes toward mutualistic endosymbiosis of microbes with plants, a system where the endophyte must function within the constraints of an in-host existence, including a dependency on the host for nutrient acquisition. Functional characterization of one such protein, SreA from , a fungal endosymbiont of cool-season grasses, indicates that regulation of iron homeostasis processes is important for symbiotic maintenance.

Complex epigenetic regulation of alkaloid biosynthesis and host interaction by heterochromatin protein I in a fungal endophyte-plant symbiosis.

Epichloë festucae forms mutualistic symbiotic interactions with grasses of the Lolium and Festuca genera. Protection from insect and mammalian herbivory are the best-documented host benefits of these associations. The two main classes of anti-mammalian alkaloids synthesized by E.

Seed Transmission of Endophytes in Is Heavily Influenced by Host Genetics.

Vertical transmission of symbiotic endophytes from host grasses into progeny seed is the primary mechanism by which the next generation of plants is colonized. This process is often imperfect, resulting in endophyte-free seedlings which may have poor ecological fitness if the endophyte confers protective benefits to its host. In this study, we investigated the influence of host genetics and environment on the vertical transmission of var.

Epichloë hybrida, sp. nov., an emerging model system for investigating fungal allopolyploidy.

Endophytes of the genus Epichloë (Clavicipitaceae, Ascomycota) frequently occur within cool-season grasses and form interactions with their hosts that range from mutualistic to antagonistic. Many Epichloë species have arisen via interspecific hybridization, resulting in species with two or three subgenomes that retain all or nearly all of their original parental genomes, a process termed allopolyploidization. Here, we characterize Epichloë hybrida, sp.

Contrasting roles of fungal siderophores in maintaining iron homeostasis in Epichloë festucae.

The symbiosis between Epichloë festucae and its host perennial ryegrass (Lolium perenne) is a model system for mutualistic interactions in which the fungal endophyte grows between plant shoot cells and acquires host nutrients to survive. E. festucae synthesises the siderophore epichloënin A (EA) via SidN, a non-ribosomal peptide synthetase (NRPS).

cAMP Signaling Regulates Synchronised Growth of Symbiotic Fungi with the Host Grass .

The seed-transmitted fungal symbiont, , colonizes grasses by infecting host tissues as they form on the shoot apical meristem (SAM) of the seedling. How this fungus accommodates the complexities of plant development to successfully colonize the leaves and inflorescences is unclear. Since adenosine 3', 5'-cyclic monophosphate (cAMP)-dependent signaling is often essential for host colonization by fungal pathogens, we disrupted the cAMP cascade by insertional mutagenesis of the adenylate cyclase gene ().

Fungal endophytes for sustainable crop production.

This minireview highlights the importance of endophytic fungi for sustainable agriculture and horticulture production. Fungal endophytes play a key role in habitat adaptation of plants resulting in improved plant performance and plant protection against biotic and abiotic stresses. They encode a vast variety of novel secondary metabolites including volatile organic compounds.

A novel family of cyclic oligopeptides derived from ribosomal peptide synthesis of an in planta-induced gene, gigA, in Epichloë endophytes of grasses.

Fungal endophytes belonging to the genus Epichloë form associations with temperate grasses belonging to the sub-family Poöideae that range from mutualistic through to pathogenic. We previously identified a novel endophyte gene (designated gigA for grass induced gene) that is one of the most abundantly expressed fungal transcripts in endophyte-infected grasses and which is distributed and highly expressed in a wide range of Epichloë grass associations. Molecular and biochemical analyses indicate that gigA encodes a small secreted protein containing an imperfect 27 amino acid repeat that includes a kexin protease cleavage site.

An extracellular siderophore is required to maintain the mutualistic interaction of Epichloë festucae with Lolium perenne.

We have identified from the mutualistic grass endophyte Epichloë festucae a non-ribosomal peptide synthetase gene (sidN) encoding a siderophore synthetase. The enzymatic product of SidN is shown to be a novel extracellular siderophore designated as epichloënin A, related to ferrirubin from the ferrichrome family. Targeted gene disruption of sidN eliminated biosynthesis of epichloënin A in vitro and in planta.