Variation In Reproduction Research Articles

Sex expression and floral diversity in Jatropha curcas: a population study in its center of origin.

Sex expression and floral morphology studies are central to understand breeding behavior and to define the productive potential of plant genotypes. In particular, the new bioenergy crop Jatropha curcas L. has been classified as a monoecious species. Nonetheless, there is no information about its reproductive diversity in the Mesoamerican region, which is considered its center of origin and diversification. Thus, we determined sex expression and floral morphology in J. curcas populations from southern Mexico and Guatemala. Our results showed that most of J. curcas specimens had typical inflorescences with separate sexes (monoecious); meanwhile, the rest were atypical (gynoecious, androecious, andromonoecious, androgynomonoecious). The most important variables to group these populations, based on a discriminant analysis, were: male flower diameter, female petal length and male nectary length. From southern Mexico “Guerrero” was the most diverse population, and “Centro” had the highest variability among the populations from Chiapas. A cluster analysis showed that the accessions from southern Mexico were grouped without showing any correlation with the geographical origin, while those accessions with atypical sexuality were grouped together. To answer the question of how informative are floral morphological traits compared to molecular markers, we perform a Mantel correlation test between the distance matrix generated in this study and the genetic distance matrix (AFLP) previously reported for the same accessions. We found significant correlation between data at the level of accessions. Our results contribute to design genetic improvement programs by using sexually and morphologically contrasting plants from the center of origin.

Microbial variability in growth and heat resistance of a pathogen and a spoiler: All variabilities are equal but some are more equal than others

Quantitative microbiology is used in risk assessment studies, microbial shelf life studies, product development, and experimental design. Realistic prediction is, however, complicated by different sources of variability. The final concentration of microorganisms at the moment of consumption is affected by different sources of variability: variability in the storage times and temperatures, variability in product characteristics, variability in process characteristics, variability in the initial contamination of the raw materials, and last but not least, microbiological variability.This article compares different sources of microbiological variability in growth and inactivation kinetics of a pathogen and a spoiler, namely experimental variability, reproduction variability (within strain variability), strain variability (between strain variability) and variability between individual cells within a population (population heterogeneity). Comparison of the different sources of microbiological variability also allows to prioritize their importance. In addition, the microbiological variability is compared to other variability factors encountered in a model food chain to evaluate the impact of different variability factors on the variability in microbial levels encountered in the final product.

The population ecology of male gametophytes: the link between pollination and seed production.

The fate of male gametophytes after pollen reaches stigmas links pollination to ovule fertilisation, governing subsequent siring success and seed production. Although male gametophyte performance primarily involves cellular processes, an ecological analogy may expose insights into the nature and implications of male gametophyte success. We elaborate this analogy theoretically and present empirical examples that illustrate associated insights. Specifically, we consider pollen loads on stigmas as localised populations subject to density-independent mortality and density-dependent processes as they traverse complex stylar environments. Different combinations of the timing of pollen-tube access to limiting stylar resources (simultaneous or sequential), the tube distribution among resources (repulsed or random) and the timing of density-independent mortality relative to competition (before or after) create signature relations of mean pollen-tube success and its variation among pistils to pollen receipt. Using novel nonlinear regression analyses (two-moment regression), we illustrate contrasting relations for two species, demonstrating that variety in these relations is a feature of reproductive diversity among angiosperms, rather than merely a theoretical curiosity. Thus, the details of male gametophyte ecology should shape sporophyte reproductive success and hence the dynamics and structure of angiosperm populations.

Diverse ecological relations of male gametophyte populations in stylar environments.

Pollen on a stigma represents a local population of male gametophytes vying for access to female gametophytes in the associated ovary. As in most populations, density-independent and density-dependent survival depend on intrinsic characteristics of male gametophytes and environmental (pistil) conditions. These characteristics and conditions could differ among flowers, plants, populations, and species, creating diverse male-gametophyte population dynamics, which can influence seed siring and production. For nine species, we characterized the relations of both the mean and standard deviation of pollen-tube number at the style base to pollen receipt with nonlinear regression. Models represented asymptotic or peaked relations, providing information about the incidence and magnitude of facilitation and competition, the spatial and temporal characteristics of competition, and the intensity and relative timing of density-independent mortality. We infer that pollen tubes of most species competed sequentially, their tips ceasing growth if earlier tubes had depleted stylar space/resources; although two species experienced simultaneous competition. Tube success of three species revealed positive density dependence (facilitation) at low density. For at least four species, density-independent mortality preceded competition. Tube success varied mostly within plants, rather than among plants or conspecific populations. Pollen quality influenced tube success for two of three species; affecting density-independent survival in one and density-dependent performance in the other. The diverse relations of pollen-tube success to pollen receipt evident among just nine species indicate significant contributions of the processes governing pollen germination and tube growth to the reproductive diversity of angiosperms.

The remarkable reproductive diversity of teleost fishes

AbstractTeleosts display the most striking reproductive diversity of all vertebrates. However, no convincing hypothesis has yet been proposed to explain why they have evolved this remarkable variability in their modes of reproduction. Some of the features of the reproductive biology of teleosts are briefly reviewed, and unique characteristics of the group that may have made possible the evolution of their remarkable reproductive diversity are considered. These include whole‐genome duplication, the mode of differentiation of the gonads and the organization of the brain–pituitary relationship.

The genome of an Encephalitozoon cuniculi type III strain reveals insights into the genetic diversity and mode of reproduction of a ubiquitous vertebrate pathogen.

Encephalitozoon cuniculi is a model microsporidian species with a mononucleate nucleus and a genome that has been extensively studied. To date, analyses of genome diversity have revealed the existence of four genotypes in E. cuniculi (EcI, II, III and IV). Genome sequences are available for EcI, II and III, and are all very divergent, possibly diploid and genetically homogeneous. The mechanisms that cause low genetic diversity in E. cuniculi (for example, selfing, inbreeding or a combination of both), as well as the degree of genetic variation in their natural populations, have been hard to assess because genome data have been so far gathered from laboratory-propagated strains. In this study, we aim to tackle this issue by analyzing the complete genome sequence of a natural strain of E. cuniculi isolated in 2013 from a steppe lemming. The strain belongs to the EcIII genotype and has been designated EcIII-L. The EcIII-L genome sequence harbors genomic features intermediate to known genomes of II and III lab strains, and we provide primers that differentiate the three E. cuniculi genotypes using a single PCR. Surprisingly, the EcIII-L genome is also highly homogeneous, harbors signatures of heterozygosity and also one strain-specific single-nucleotide polymorphism (SNP) that introduces a stop codon in a key meiosis gene, Spo11. Functional analyses using a heterologous system demonstrate that this SNP leads to a deficient meiosis in a model fungus. This indicates that EcIII-L meiotic machinery may be presently broken. Overall, our findings reveal previously unsuspected genome diversity in E. cuniculi, some of which appears to affect genes of primary importance for the biology of this pathogen.

Local variability in growth and reproduction of Salix arctica in the High Arctic

Arctic terrestrial ecosystems are heterogeneous because of the strong influences of microtopography, soil moisture and snow accumulation on vegetation distribution. The interaction between local biotic and abiotic factors and global climate patterns will influence species responses to climate change. Salix arctica (Arctic willow) is a structuring species, ubiquitous and widespread, and as such is one of the most important shrub species in the High Arctic. In this study, we measured S. arctica reproductive effort, early establishment, survival and growth in the Zackenberg valley, north-east Greenland. We sampled four plant communities that varied with respect to snow conditions, soil moisture, nutrient content and plant composition. We found large variability in reproductive effort and success with total catkin density ranging from 0.6 to 66 catkins/m 2 and seedling density from <1 to 101 seedlings/m 2 . There were also major differences in crown area increment (4–23 cm 2 /year) and stem radial growth (40–74 µm/year). The snowbed community, which experienced a recent reduction in snow cover, supported young populations with high reproductive effort, establishment and growth. Soil nutrient content and herbivore activity apparently did not strongly constrain plant reproduction and growth, but competition by Cassiope tetragona and low soil moisture may inhibit performance. Our results show that local environmental factors, such as snow accumulation, have a significant impact on tundra plant response to climate change and will affect the understanding of regional vegetation response to climate change. Keywords: Herbivory; nutrient; plant colonization; vegetation; shrub; water availability. (Published: 27 June 2016) To access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools). Citation: Polar Research 2016, 35 , 24126, http://dx.doi.org/10.3402/polar.v35.24126

Cultural and Reproductive Variability of Corynespora cassiicola from Different Host Plants

Natural rubber industry plays an important role in the economy of Sri Lanka. Therefore, improvement of productivity levels has become important. Corynespora leaf fall disease (CLFD) is the most destructive disease of rubber caused by Corynespora cassiicola. In Sri Lanka two epidemics occurred in 1986 and 1995. C. cassiicola has a wide host range including vegetables, ornamentals, weeds, yams, medicinal and other cash crops. Hence, there is a high risk of cross infection possibilities. The objective of this study was to examine the diversity of the pathogen isolates from several host plants; rubber-RRISL202 (A), RRISL 110 (B), RRISL201 (C), Eggplant (D), Papaya (E), Tomato (F). Diseased leaf samples were collected and isolated on potato dextrose agar (PDA). Single spore isolates were obtained and the cultural variations were studied. Except flat textured D and E, all the other isolates showed puffy growth. Colony appearance varied from olivaceous green colour to different shades of grey. Except A, B and C all the other isolates showed concentric rings on lower surface. Except A and B, the other isolates showed uneven margins. In microscopic view, all rubber isolates showed thread like hyphae with a width of (3.20-3.58) μm. However, in the isolates of alternative hosts, hyphae were wider (6.00-7.80 μm). Generally mycelia were branched and septate with conidiophores at the tips of hyphae. Isolates A, B and C were fast growers, D and E were moderate while F was slow. In reproductive studies, generally conidia of C. cassiicola were segmented and showed characteristic hilum at the pointed tips. There was no significant variation in the dimensions of spores among the isolates. The conidial length varied from (15-275 μm) and width varied from (3.75-12.50 μm). Straight, curved, cylindrical and obclavate shapes were observed. Mostly slender, straight conidia were observed in rubber isolates. Rubber isolates were poor sporulators compared to the alternative host isolates. Present study revealed that there is a significant variation in the morphology and reproductive characteristics among the selected C. cassiicola isolates. Further investigations will be carried out to examine the genetic and pathogenicity variations among the isolates. Keywords: Corynespora cassiicola, Alternative hosts, Morphology and reproductive Characteristics

Assessing the potential for intrinsic recovery in a Collembola two-generation study: possible implementation in a tiered soil risk assessment approach for plant protection products

Collembola are soil dwelling organisms that provide important ecosystem services within soils. To increase realism in evaluating potential effects of plant protection products a Collembola two-generation study was developed. This test assesses the potential for recovery of Collembola when exposed to plant protection products. Juvenile individuals of Folsomia candida (Willem, Ann Soc Entomol Belg 46:275-283, 1902) which hatched under conditions of exposure to a test substance in a modified OECD 232 bioassay were introduced into a second consecutive bioassay containing the same test substance aged in soil. This test system determines whether a population which was initially impacted by a substance in a 1st bioassay shows normal reproduction or survival in a 2nd bioassay after aging of the test substance in soil. An intermediate period for juvenile growth is included between the 1st and 2nd bioassay in order to reduce the control treatment variability in reproduction and mortality to fulfill the validity criteria according to the OECD 232 guideline. The Collembola two-generation study is able to differentiate between substances showing either a potential long-term risk or comprising a low risk. Comparing the results of this two generation study with data from semi-field or field studies indicates a high degree of conservatism when this test is considered within a tiered risk assessment scheme. This approach represents a valuable tool which makes the risk assessment more efficient by providing an alternative refinement option for highly conservative tier 1 Collembola risk assessment.

Toward Selective Breeding of a Hermaphroditic OysterOstrea chilensis: Roles of Nutrition and Temperature in Improving Fecundity and Synchrony of Gamete Release

ABSTRACT Physiological characteristics of gametogenesis, fertilization, and early larval development in Ostrea chilensis (Philippi, 1845) pose a number of challenges for selective breeding, despite strong commercial potential. In wild populations, this larviparous protandric hermaphrodite exhibits asynchronous gonadal maturation and relatively low fecundity. Reproductive success and genetic diversity in a hatchery population are primarily determined by female fecundity and fertility, as well as synchrony of female gonad development. Better hatchery control of the reproductive cycle can lead to more cost-effective and reliable breeding. This study examined factors such as feed and temperature in an attempt to increase reproductive rates and female sex ratios in brood stock. Oysters held under two different hatchery conditioning regimes—flow-through outdoor nursery ponds and temperature-controlled indoor tanks—spawned earlier and had higher reproductive rates than natural or farmed populations. Oysters were...

The biogeography of fertilization mode in the sea

AbstractAimKnowledge of the biogeography of life histories is central to understanding and predicting the impacts of global change on key functional traits that shape species distributions and transcend taxonomic boundaries. Whether species are internal or external fertilizers is a fundamental aspect of reproductive diversity in the sea, and has profound ecological and evolutionary consequences. However, geographic variation in this trait and the factors that potentially drive it (e.g. transitions in associated life‐history traits, ecological conditions that favour one mode over the other or the evolutionary history of species) remain poorly characterized.LocationOceans world‐wide.MethodsWe collated life‐history data (modes of fertilization and development), geographic data and biophysical data (sea‐surface temperatures and food availability) for 1532 marine species spanning 17 invertebrate phyla. We used standard and phylogenetic logistic regressions to evaluate latitudinal gradients in fertilization mode, plus their interactions with development (transitions from planktonic to aplanktonic development, or from feeding to non‐feeding larvae) and taxonomy. We also explored the dependence of fertilization mode on biophysical variables to understand how ecology potentially contributes to geographic variation in this trait.ResultsFertilization mode often varies predictably with latitude, but the exact nature of this relationship depends on developmental mode and the phylum under consideration. Some commonalities were evident, however, with the likelihood of internal fertilization declining at higher latitudes for Annelida and Echinodermata with aplanktonic development, but increasing at higher latitudes for Cnidaria and Porifera with non‐feeding, planktonic larvae. Synergistic effects of temperature and food availability may potentially shape some of these patterns.Main conclusionsThere are latitudinal gradients in fertilization mode in the sea. The variation among phyla and developmental modes, however, is a complexity that is unexplained by existing theory. Combined effects of recent adaptation and deeper phylogenetic history have probably shaped this systematic variation in the reproductive ecology of marine organisms.

Determinants of male floating behaviour and floater reproduction in a threatened population of the hihi (Notiomystis cincta).

Floating males are usually thought of as nonbreeders. However, some floating individuals are able to reproduce through extra-pair copulations. Floater reproductive success can impact breeders’ sex ratio, reproductive variance, multiple paternity and inbreeding, particularly in small populations. Changes in reproductive variance alter the rate of genetic drift and loss of genetic diversity. Therefore, genetic management of threatened species requires an understanding of floater reproduction and determinants of floating behaviour to effectively conserve species. Here, we used a pedigreed, free-living population of the endangered New Zealand hihi (Notiomystis cincta) to assess variance in male reproductive success and test the genetic (inbreeding and heritability) and conditional (age and size) factors that influence floater behaviour and reproduction. Floater reproduction is common in this species. However, floater individuals have lower reproductive success and variance in reproductive success than territorial males (total and extra-pair fledglings), so their relative impact on the population's reproductive performance is low. Whether an individual becomes a floater, and if so then how successful they are, is determined mainly by individual age (young and old) and to lesser extents male size (small) and inbreeding level (inbred). Floating males have a small, but important role in population reproduction and persistence of threatened populations.

Evolution of dosage compensation under sexual selection differs between X and Z chromosomes

Complete sex chromosome dosage compensation has more often been observed in XY than ZW species. In this study, using a population genetic model and the chicken transcriptome, we assess whether sexual conflict can account for this difference. Sexual conflict over expression is inevitable when mutation effects are correlated across the sexes, as compensatory mutations in the heterogametic sex lead to hyperexpression in the homogametic sex. Coupled with stronger selection and greater reproductive variance in males, this results in slower and less complete evolution of Z compared with X dosage compensation. Using expression variance as a measure of selection strength, we find that, as predicted by the model, dosage compensation in the chicken is most pronounced in genes that are under strong selection biased towards females. Our study explains the pattern of weak dosage compensation in ZW systems, and suggests that sexual selection plays a major role in shaping sex chromosome dosage compensation.

Assessment of census (N) and effective population size (N e ) reveals consistency of N e single-sample estimators and a high N e /N ratio in an urban and isolated population of fire salamanders

Amphibians are the most threatened vertebrates on Earth, and one of the main factors involved in their decline is the loss and fragmentation of their natural habitats. Contemporary urban development is a major cause of habitat fragmentation, and populations trapped within urban environments offer a unique opportunity to study effects of fragmentation. Here, we compared, for the first time in fire salamanders (Salamandra salamandra), estimates of census (N) and effective population size (N e ) in a small urban population in the city of Oviedo (Spain). We performed a 4 year capture-mark-recapture study and used three single-sample N e estimators based on 58 individuals genotyped for 15 polymorphic microsatellite loci. Our study showed a small ( $$\hat{N} = 113$$ salamanders; 95 % CI 100–142) but dense population (mean 0.45 individuals per m2), while single-sample estimators provided congruent N e estimates. A high N e /N population size ratio (range 0.50–0.84) obtained in this small and isolated population suggests the existence of mechanisms of genetic compensation (low reproductive variance and multiple paternity) in fire salamanders.

Quantifying strain variability in modeling growth of Listeria monocytogenes

Prediction of microbial growth kinetics can differ from the actual behavior of the target microorganisms. In the present study, the impact of strain variability on maximum specific growth rate (μmax) (h−1) was quantified using twenty Listeria monocytogenes strains. The μmax was determined as function of four different variables, namely pH, water activity (aw)/NaCl concentration [NaCl], undissociated lactic acid concentration ([HA]), and temperature (T). The strain variability was compared to biological and experimental variabilities to determine their importance. The experiment was done in duplicate at the same time to quantify experimental variability and reproduced at least twice on different experimental days to quantify biological (reproduction) variability. For all variables, experimental variability was clearly lower than biological variability and strain variability; and remarkably, biological variability was similar to strain variability. Strain variability in cardinal growth parameters, namely pHmin, [NaCl]max, [HA]max, and Tmin was further investigated by fitting secondary growth models to the μmax data, including a modified secondary pH model. The fitting results showed that L. monocytogenes had an average pHmin of 4.5 (5–95% prediction interval (PI) 4.4–4.7), [NaCl]max of 2.0mM (PI 1.8–2.1), [HA]max of 5.1mM (PI 4.2–5.9), and Tmin of −2.2°C (PI (−3.3)–(−1.1)). The strain variability in cardinal growth parameters was benchmarked to available literature data, showing that the effect of strain variability explained around 1/3 or less of the variability found in literature. The cardinal growth parameters and their prediction intervals were used as input to illustrate the effect of strain variability on the growth of L. monocytogenes in food products with various characteristics, resulting in 2–4 logCFU/ml(g) difference in growth prediction between the most and least robust strains, depending on the type of food product. This underlined the importance to obtain quantitative knowledge on variability factors to realistically predict the microbial growth kinetics.

Age and sex-specific mortality of wild and captive populations of a monogamous pair-bonded primate (Aotus azarae).

In polygynous primates, a greater reproductive variance in males have been linked to their reduced life expectancy relative to females. The mortality patterns of monogamous pair-bonded primates, however, are less clear. We analyzed the sex differences in mortality within wild (NMales = 70, NFemales = 73) and captive (NMales = 25, NFemales = 29) populations of Azara's owl monkeys (Aotus azarae), a socially and genetically monogamous primate exhibiting biparental care. We used Bayesian Survival Trajectory Analysis (BaSTA) to test age-dependent models of mortality. The wild and captive populations were best fit by the logistic and Gompertz models, respectively, implying greater heterogeneity in the wild environment likely due to harsher conditions. We found that age patterns of mortality were similar between the sexes in both populations. We calculated life expectancy and disparity, the latter a measure of the steepness of senescence, for both sexes in each population. Males and females had similar life expectancies in both populations; the wild population overall having a shorter life expectancy than the captive one. Furthermore, captive females had a reduced life disparity relative to captive males and to both sexes in the wild. We interpret this pattern in light of the hazards associated with reproduction. In captivity, where reproduction is intensely managed, the risks associated with gestation and birth are tempered so that there is a reduction in the likelihood of captive females dying prematurely, decreasing their overall life disparity.

Characterization of Brazilian populations of Pratylenchus brachyurus using morphological and molecular analyses

In Brazil, Pratylenchus brachyurus damages economic important crops and it is managed with non-chemical methods such as crop rotation or resistant cultivars. However, the variability in reproduction and damaging effects observed among P. brachyurus populations could limit the efficacy and long lasting effect of nematode control practices. Twelve populations of P. brachyurus from different geographical areas of Brazil were analyzed morphologically and molecularly. The morphological and morphometric characters of the populations studied were variable, but fitted those of P. brachyurus. Assemblages of populations with different host preferences and reproductive capabilities were revealed by PCA of these populations using selected morphological characters. Phylogenetic analysis using ITS-rDNA sequences distinguished statistically supported groups of sequences that matched those of other populations of P. brachyurus deposited in the GenBank, confirming the identity of populations here studied. Intraspecific sequence diversity was observed among the populations. These variant sequences suggest the presence of microheterogeneity between ITS-1 copies in individuals. The findings of this study did not provide evidence of cryptic species in the P. brachyurus populations studied. The variability within and among populations of P. brachyurus observed in this work must be taken into consideration in breeding programs for resistance to this nematode.

The impact of environmental variability on Atlantic mackerel Scomber scombrus larval abundance to the west of the British Isles

The value of the Continuous Plankton Recorder (CPR) fish larvae dataset, with its extensive spatio-temporal coverage, has been recently demonstrated with studies on long-term changes over decadal scales in the abundance and distribution of fish larvae in relation to physical and biological factors in the North Sea. We used a similar approach in the west and southwest area of the UK shelf and applied a principal component analysis (PCA) using 7 biotic and abiotic parameters, combined with Hierarchical Cluster Analysis (HCA), to investigate the impact of environmental changes in the west and southwest area of the UK shelf on mackerel larvae during the period 1960–2004. The analysis revealed 3 main periods of time (1960–1968; 1969–1994; 1995–2004) reflecting 3 different ecosystem states. The results suggest a transition from an ecosystem characterized by low temperature, high salinity, high abundances of zooplankton and the larger phytoplankton groups, to a system characterized by higher temperature, lower salinities, lower abundances of zooplankton and larger phytoplankton and higher abundances of the small phytoplankton species. Analysis revealed a very weak positive correlation between the Second principal component and mackerel larvae yearly abundance, attributed to the North Atlantic Oscillation (NAO). The results presented here are in broad accord with recent investigations that link climatic variability and dynamics of mackerel reproduction. However, the growing body of literature that documents statistical correlations between environment and mackerel needs to be supplemented by local process studies, to gain more insight and to be able to predict mackerel response to climate change scenarios. Utilising the strength of the CPR dataset, namely its unique temporal coverage, in an analysis where other data (such as egg surveys) are drawn in to compensate for the spatial issues could prove to be the way forward.

Reward quality predicts effects of bird-pollinators on the reproduction of African Protea shrubs

Pollination syndromes predict the principal animal pollinators of plant species from floral traits. However, the existence of discrete pollination syndromes and the relevance of these syndromes for the effects of animal pollinators on plant reproduction are controversial and a quantitative, trait-based approach may refine the concept of pollination syndromes. Thus far, however, very few studies have simultaneously analysed the importance of signalling, accessibility and reward traits of flowers for the effects of animal pollinators on plant reproduction of multiple species. The genus Protea is an ideal study system because the members of this genus exhibit remarkable variation in functional traits and Protea species are visited by several guilds of animal pollinators, such as birds and insects. We experimentally investigated seven Protea species from the South African fynbos to assess variability in reproduction (seed set, seed mass, germination) in response to pollinator exclusion (full-exclusion, bird-exclusion) and hand-pollination (self-pollen, cross-pollen). To generalise the findings of the experiment, we conducted a meta-analysis of the effects of bird-exclusion on seed set of 14 Protea species, associating effect sizes of bird-pollination with signalling (inflorescence length and diameter), accessibility (inflorescence and style length) and reward traits (length of pollen presenter, nectar volume and sugar concentration). All Protea species were self-compatible, but only two species were to a small degree capable of autonomous selfing. Protea species varied in their dependence on animal pollinators, including species depending exclusively on birds, insects, or both for seed production. Protea species exhibited continuous variation in the effects of bird-pollinators on reproduction, challenging the accuracy of categorical pollination syndromes for predicting pollinator effects on plant reproduction. The meta-analysis showed that the quality of floral rewards, especially nectar sugar concentration, predicts the dependence of Protea reproduction on bird pollinators, whereas the signalling and accessibility traits tested in this study were not important. Beyond revealing new insights into the pollination biology of Protea species, our findings underscore the usefulness of experimental approaches on multiple plant species to test the effects of pollinator guilds on plant reproduction and contribute to a trait-based understanding of the functional determinants of plant–pollinator interactions.

Asexual propagation of a virulent clone complex in a human and feline outbreak of sporotrichosis.

Sporotrichosis is one of the most frequent subcutaneous fungal infections in humans and animals caused by members of the plant-associated, dimorphic genus Sporothrix. Three of the four medically important Sporothrix species found in Brazil have been considered asexual as no sexual stage has ever been reported in Sporothrix schenckii, Sporothrix brasiliensis, or Sporothrix globosa. We have identified the mating type (MAT) loci in the S. schenckii (strain 1099-18/ATCC MYA-4821) and S. brasiliensis (strain 5110/ATCC MYA-4823) genomes by using comparative genomic approaches to determine the mating type ratio in these pathogen populations. Our analysis revealed the presence of a MAT1-1 locus in S. schenckii while a MAT1-2 locus was found in S. brasiliensis representing genomic synteny to other Sordariomycetes. Furthermore, the components of the mitogen-activated protein kinase (MAPK)-pheromone pathway, pheromone processing enzymes, and meiotic regulators have also been identified in the two pathogens, suggesting the potential for sexual reproduction. The ratio of MAT1-1 to MAT1-2 was not significantly different from 1:1 for all three Sporothrix species, but the population of S. brasiliensis in the outbreaks originated from a single mating type. We also explored the population genetic structure of these pathogens using sequence data of two loci to improve our knowledge of the pattern of geographic distribution, genetic variation, and virulence phenotypes. Population genetics data showed significant population differentiation and clonality with a low level of haplotype diversity in S. brasiliensis isolates from different regions of sporotrichosis outbreaks in Brazil. In contrast, S. schenckii isolates demonstrated a high degree of genetic variability without significant geographic differentiation, indicating the presence of recombination. This study demonstrated that two species causing the same disease have contrasting reproductive strategies and genetic variability patterns.