Disparate independent genetic events disrupt the secondary metabolism gene perA in certain symbiotic Epichloë species.
نویسندگان
چکیده
Peramine is an insect-feeding deterrent produced by Epichloë species in symbiotic association with C3 grasses. The perA gene responsible for peramine synthesis encodes a two-module nonribosomal peptide synthetase. Alleles of perA are found in most Epichloë species; however, peramine is not produced by many perA-containing Epichloë isolates. The genetic basis of these peramine-negative chemotypes is often unknown. Using PCR and DNA sequencing, we analyzed the perA genes from 72 Epichloë isolates and identified causative mutations of perA null alleles. We found nonfunctional perA-ΔR* alleles, which contain a transposon-associated deletion of the perA region encoding the C-terminal reductase domain, are widespread within the Epichloë genus and represent a prevalent mutation found in nonhybrid species. Disparate phylogenies of adjacent A2 and T2 domains indicated that the deletion of the reductase domain (R*) likely occurred once and early in the evolution of the genus, and subsequently there have been several recombinations between those domains. A number of novel point, deletion, and insertion mutations responsible for abolishing peramine production in full-length perA alleles were also identified. The regions encoding the first and second adenylation domains (A1 and A2, respectively) were common sites for such mutations. Using this information, a method was developed to predict peramine chemotypes by combining PCR product size polymorphism analysis with sequencing of the perA adenylation domains.
منابع مشابه
Disparate Independent Genetic Events Disrupt the Secondary Metabolism Gene <em>perA</em> in Certain Symbiotic <em>Epichloë</em> Species
متن کامل
A novel test for significant codivergence between cool-season grasses and their symbiotic fungal endophytes
Symbioses of grasses and fungal endophytes constitute an interesting model for evolution of mutualism and parasitism. Grasses of all subfamilies can harbor systemic infections by fungi of the family Clavicipitaceae. Subfamily Poöideae is specifically associated with epichloë endophytes (species of Epichloë and their asexual derivatives, the Neotyphodium species) in intimate symbioses often char...
متن کاملTwo distinct Epichloë species symbiotic with Achnatherum inebrians, drunken horse grass.
Achnatherum inebrians, colloquially known as drunken horse grass, is associated with livestock toxicity in northern China. Epichloë gansuensis (Eg) was described from endophyte isolates from A. inebrians in Sunan County, Gansu Province, whereas a morphologically distinct variety, E. gansuensis var. inebrians (Ei), was described based on two isolates from A. inebrians seeds collected in Urumqi C...
متن کاملAnalysis of simple sequence repeat (SSR) structure and sequence within Epichloë endophyte genomes reveals impacts on gene structure and insights into ancestral hybridization events
Epichloë grass endophytes comprise a group of filamentous fungi of both sexual and asexual species. Known for the beneficial characteristics they endow upon their grass hosts, the identification of these endophyte species has been of great interest agronomically and scientifically. The use of simple sequence repeat loci and the variation in repeat elements has been used to rapidly identify endo...
متن کاملVegetative Hyphal Fusion and Subsequent Nuclear Behavior in Epichloë Grass Endophytes
Epichloë species (including the former genus Neotyphodium) are fungal symbionts of many agronomically important forage grasses, and provide their grass hosts with protection from a wide range of biotic and abiotic stresses. Epichloë species include many interspecific hybrids with allodiploid-like genomes, which may provide the potential for combined traits or recombination to generate new trait...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Applied and environmental microbiology
دوره 81 8 شماره
صفحات -
تاریخ انتشار 2015