Biology subjects

Moghadam, N. N.

Publications and source records attributed to Moghadam, N. N..

4 recordsLinked to original sources

bioRxiv2024

Genome-wide association for loci influencing thermal performance curves in Neurospora crassa

Temperature poses a unique challenge to ectothermic species, as it affects all biochemical reactions in the cell and causes physiological stress. The effect of temperature on an organism can be described by a thermal performance curve (TPC), which displays organismal performance, such as growth rate, as a function of temperature. Previous studies on thermal performance have revealed different amounts of genetic variation and trade-offs in TPC shape and position within species and populations. However, very little is known about the genetic architecture of TPCs on the level of individual loci and alleles. We asked what is the identity of loci contributing to genetic variation in TPCs, and do the alleles exhibit trade-offs or thermodynamic scaling across the temperature range? We used genome-wide association mapping to find loci influencing growth rate at different temperatures and TPC traits in the filamentous fungus Neurospora crassa. We also evaluated the directions and magnitudes of allelic effects to investigate possible trade-offs. We observed both unique associations at specific temperatures, as some loci affected growth rate only at low, intermediate, or high temperatures, and associations that were shared across multiple temperatures. However, only weak evidence of trade-offs was detected, indicating that the evolution of TPCs in N. crassa is not constrained by allelic effects in opposite directions at hot and cold temperatures. Our findings indicate that trade-offs contribute little to variation in TPCs.

genetics↗

bioRxiv2022

Parental effects in a filamentous fungus: phenotype, fitness, and mechanism

Adaptation to changing environments often requires meaningful phenotypic modifications to match the current conditions. However, obtaining information about the surroundings during an organisms own lifetime may only permit accommodating relatively late developmental modifications. Therefore, it may be advantageous to rely on inter-generational or trans-generational cues that provide information about the environment as early as possible to allow development along an optimal trajectory. Transfer of information or resources across generations, known as parental effects, is well documented in animals and plants but not in other eukaryotes, such as fungi. Understanding parental effects and their evolutionary consequences in fungi is of vital importance as they perform crucial ecosystem functions. In this study, we investigated whether parental effects are present in the filamentous fungus Neurospora crassa, how long do they last, are the effects adaptive, and what is their mechanism. We performed a fully factorial match / mismatch experiment for a good and poor quality environment, in which we measured mycelium size of strains that experienced either a matched or mismatched environment in their previous generation. We found a strong silver spoon effect in initial mycelium growth, which lasted for one generation, and increased fitness during competition experiments. By using deletion mutants that lacked key genes in epigenetic processes, we show that epigenetic mechanisms are not involved in this effect. Instead, we show that spore glycogen content, glucose availability and a radical transcription shift in spores are the main mechanisms behind this parental effect.

microbiology↗

bioRxiv2022

Host's genetic background determines the outcome of reciprocal faecal transplantation on life-history traits and microbiome composition

BackgroundMicrobes play a role in fundamental ecological, chemical, and physiological processes of their host. Host life-history traits from defence to growth are therefore determined not only by abiotic environment and genotype but also by microbiota composition. However, the relative importance and interactive effects of these factors may vary between organisms. Such connections remain particularly elusive in Lepidoptera, which have been argued to lack a permanent microbiome and have microbiota primarily determined by their diet and environment. We tested the microbiome specificity and its influence on life-history traits of two colour genotypes of the wood tiger moth (Arctia plantaginis) that differ in several traits, including growth. All individuals were grown in the laboratory for several generations with standardised conditions. We analysed the bacterial community of the genotypes before and after a reciprocal frass (i.e., larval faeces) transplantation and followed growth rate, pupal mass, and the production of defensive secretion. ResultsAfter transplantation, the fast-growing genotype grew at a significantly slower rate compared to the controls, but the slow-growing genotype did not change its growth rate. The frass transplant also increased the volume of defensive secretions in the fast-growing genotype but did not affect pupal mass. Overall, the fast-growing genotype appeared more susceptible to the transplantation than the slow-growing genotype. Microbiome differences between the genotypes strongly suggest genotype-based selective filtering of bacteria from the diet and environment. A novel cluster of insect-associated Erysipelotrichaceae was exclusive to the fast-growing genotype, and specific Enterococcaceae were characteristic to the slow-growing genotype. These Enterococcaceae became more prevalent in the fast-growing genotype after the transplant, which suggests that the slower growth rate was potentially related to their presence. ConclusionsWe show that some genotype-specific life-history traits in a lepidopteran host can be reversed by a reciprocal frass transplantation. The results indicate that genotype-specific selective filtering can fine-tune the bacterial community at specific life stages, particularly the larval gut, even against a background of a highly variable community with stochastic assembly. Altogether, our findings suggest that the genotype of the host can influence its susceptibility to be colonized by microbiota with impact on key life-history traits.

evolutionary biology↗

bioRxiv2020

Quantitative genetics of temperature performance curves of Neurospora crassa

Earths temperature is increasing due to anthropogenic CO2 emissions; and organisms need either to adapt to higher temperatures, migrate into colder areas, or face extinction. Temperature affects nearly all aspects of an organisms physiology via its influence on metabolic rate and protein structure, therefore genetic adaptation to increased temperature may be much harder to achieve compared to other abiotic stresses. There is still much to be learned about the evolutionary potential for adaptation to higher temperatures, therefore we studied the quantitative genetics of growth rates in different temperatures that make up the thermal performance curve of the fungal model system Neurospora crassa. We studied the amount of genetic variation for thermal performance curves and examined possible genetic constraints by estimating the G-matrix. We observed a substantial amount of genetic variation for growth in different temperatures, and most genetic variation was for performance curve elevation. Contrary to common theoretical assumptions, we did not find strong evidence for genetic trade-offs for growth between hotter and colder temperatures. We also simulated short term evolution of thermal performance curves of N. crassa, and suggest that they can have versatile responses to selection.

evolutionary biology↗