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Ecology and Evolution Jun 2024Genetic diversity can modulate a population's response to a changing environment and plays a critical role in its ecological function. While multiple processes act to...
Genetic diversity can modulate a population's response to a changing environment and plays a critical role in its ecological function. While multiple processes act to maintain genetic diversity, sexual reproduction remains the primary driving force. Eelgrass () is an important habitat-forming species found in temperate coastal ecosystems across the globe. Recent increases in sea surface temperatures have resulted in shifts to a mixed-annual life-history strategy (i.e., displaying characteristics of both annual and perennial meadows) at its southern edge-of-range. Given that mating systems are intimately linked to standing levels of genetic variation, understanding the scope of sexual reproduction can illuminate the processes that shape genetic diversity. To characterize edge-of-range eelgrass mating systems, developing seeds on flowering shoots were genotyped from three meadows in Topsail, North Carolina. In all meadows, levels of multiple mating were high, with shoots pollinated by an average of eight sires (range: 3-16). The number of fertilized seeds (i.e., reproductive success) varied significantly across sires (range: 1-25) and was positively correlated with both individual heterozygosity and self-fertilization. Outcrossing rates were high (approx. 70%) and varied across spathes. No clones were detected, and kinship among sampled flowering shoots was low, supporting observed patterns of reproductive output. Given the role that genetic diversity plays in enhancing resistance to and resilience from ecological disturbance, disentangling the links between life history, sexual reproduction, and genetic variation will aid in informing the management and conservation of this key foundation species.
PubMed: 38919644
DOI: 10.1002/ece3.11608 -
Horticulture Research Jun 2024Accurately predicting flowering phenology in fruit tree orchards is crucial for timely pest and pathogen treatments and for the introduction of managed pollinators....
Accurately predicting flowering phenology in fruit tree orchards is crucial for timely pest and pathogen treatments and for the introduction of managed pollinators. Making predictions requires large datasets of flowering dates, which are often limited to single locations. Consequently, the resulting phenology predictions are not representative across larger geographic areas. Citizen science may offer a solution to this data gap, with millions of biological records across a wide range of taxa recorded annually. Here, a new citizen science platform called 'FruitWatch' is introduced, monitoring the flowering dates of fruit trees in Great Britain. The objectives of this study are to assess the suitability of FruitWatch submissions to (i) detect latitudinal variation in flowering onset dates, (ii) parameterize existing phenology modelling frameworks, and (iii) make predictions of flowering onset dates across Great Britain for a single year. Using data for four cultivars from 2022, linear models reveal significant latitudinal delays in flowering onset of as much as 1.49 ± 0.63 days per degree latitude further north (Pear 'Conference'), with significant delays also seen in Cherry 'Stella' (1.39 ± 0.48 days) and Plum 'Victoria' (1.22 ± 0.18 days). FruitWatch informed phenology modelling frameworks performed well for predicting flowering onset, with root mean square error values of predictions from validation datasets ranging between 4.6 ('Victoria') and 8.0 ('Conference') days. The parameterized models also provided realistic flowering onset predictions across Great Britain in 2022, with earlier flowering dates predicted in warmer areas. These findings demonstrate the potential of citizen science data to offer growers cultivar- and location-specific phenology predictions to help inform orchard management.
PubMed: 38919557
DOI: 10.1093/hr/uhae122 -
Plant Communications Jun 2024Genome-wide association study (GWAS) identifies trait-associated loci, but due in part to slow decay of linkage disequilibrium (LD), identifying the causal genes can be...
Genome-wide association study (GWAS) identifies trait-associated loci, but due in part to slow decay of linkage disequilibrium (LD), identifying the causal genes can be a bottleneck. Transcriptome-wide association study (TWAS) addresses this by identifying gene expression-phenotype associations or integrating gene expression quantitative trait loci (eQTLs) with GWAS results. Here, we used self-pollinated soybean (Glycine max [L.] Merr.) as a model to evaluate the application of TWAS in the genetic dissection of traits in plant species with slow LD decay. We generated RNA-Seq data of a soybean diversity panel, and identified the genetic expression regulation of 29,286 genes in soybean. Different TWAS solutions were less affected by LD and robust with source of expression that identified known genes related to traits from different development stages and tissues. A novel gene named pod color L2 was identified via TWAS and functionally validated by genome editing. By introducing the new exon proportion feature, we significantly improved the detection of expression variations resulting from structural variations and alternative splicing. As a result, the genes identified by our TWAS approach exhibited a diverse range of causal variations, including SNP, insertion/deletion, gene fusion, copy number variation, and alternative splicing. Using our TWAS approach, we identified genes associated with flowering time, including both previously known genes and novel genes that had not previously linked to this trait before, providing complementary insights with GWAS. In summary, this study supports the application of TWAS for candidate gene identification in species with low rates of LD decay.
PubMed: 38918950
DOI: 10.1016/j.xplc.2024.101010 -
Scientific Reports Jun 2024The decline of wild bee populations causes the decline of bee-pollinated plant populations through the deterioration of pollination services. Since high bee species...
The decline of wild bee populations causes the decline of bee-pollinated plant populations through the deterioration of pollination services. Since high bee species richness generally involves high functional group diversity, protecting areas of high bee species richness will help to maintain pollination services for plants. However, those areas do not always include the habitats of bee species with specialized functions that expand the range of plants being pollinated. To map important areas for protecting native bee species and their functions, we estimated the distributions and functional range of 13 bumble bee species and 1 honey bee species in Japan. The distributions were estimated from an ensemble of six species distribution models using bee occurrence data and environmental data. The functional range of bee species was estimated by combining the estimated distributions and proboscis length, which frequently corresponds to the floral shape of the plant species they pollinate. The estimated species richness was high in western Hokkaido and the estimated functional range was wide in central Honshu. Our method is useful to see whether areas important for high species richness of pollinators differ from those for rare species or their functions.
Topics: Bees; Animals; Pollination; Japan; Biodiversity; Ecosystem
PubMed: 38918494
DOI: 10.1038/s41598-024-61848-z -
Scientific Reports Jun 2024Although pesticide-free techniques have been developed in agriculture, pesticides are still routinely used against weeds, pests, and pathogens worldwide. These...
Although pesticide-free techniques have been developed in agriculture, pesticides are still routinely used against weeds, pests, and pathogens worldwide. These agrochemicals pollute the environment and can negatively impact human health, biodiversity and ecosystem services. Acetamiprid, an approved neonicotinoid pesticide in the EU, may exert sub-lethal effects on pollinators and other organisms. However, our knowledge on the scope and severity of such effects is still incomplete. Our experiments focused on the effects of the insecticide formulation Mospilan (active ingredient: 20% acetamiprid) on the peripheral olfactory detection of a synthetic floral blend and foraging behaviour of buff-tailed bumblebee (Bombus terrestris) workers. We found that the applied treatment did not affect the antennal detection of the floral blend; however, it induced alterations in their foraging behaviour. Pesticide-treated individuals started foraging later, and the probability of finding the floral blend was lower than that of the control bumblebees. However, exposed bumblebees found the scent source faster than the controls. These results suggest that acetamiprid-containing Mospilan may disrupt the activity and orientation of foraging bumblebees. We hypothesize that the observed effects of pesticide exposure on foraging behaviour could be mediated through neurophysiological and endocrine mechanisms. We propose that future investigations should clarify whether such sub-lethal effects can affect pollinators' population dynamics and their ecosystem services.
Topics: Animals; Bees; Insecticides; Flowers; Odorants; Neonicotinoids; Pollination
PubMed: 38918480
DOI: 10.1038/s41598-024-65388-4 -
Plant Physiology Jun 2024Pollen germination and pollen tube elongation require rapid phospholipid production and remodeling in membrane systems that involve both de novo synthesis and turnover....
Pollen germination and pollen tube elongation require rapid phospholipid production and remodeling in membrane systems that involve both de novo synthesis and turnover. Phosphatidic acid phosphohydrolase (PAH) and lysophosphatidylcholine acyltransferase (LPCAT) are two key enzymes in membrane lipid maintenance. PAH generates diacylglycerol (DAG), a necessary precursor for the de novo synthesis of phosphatidylcholine (PC), while LPCAT reacylates lysophosphatidylcholine (LPC) to PC and plays an essential role in the remodeling of membrane lipids. In this study, we investigated the synthetic defects of pah and lpcat mutations in sexual reproduction of Arabidopsis (Arabidopsis thaliana) and explored the prospect of pistil lipid provision to pollen tube growth. The combined deficiencies of lpcat and pah led to decreased pollen tube growth in the pistil and reduced male transmission. Interestingly, pistils of the lipid mutant dgat1 ameliorated the male transmission deficiencies of pah lpcat pollen. In contrast, pollination with a non-specific phospholipase C (NPC) mutant exacerbated the fertilization impairment of the pah lpcat pollen. Given the importance of DAG in lipid metabolism and its contrasting changes in the dgat1 and npc mutants, we further investigated whether DAG supplement in synthetic media could influence pollen performance. DAG was incorporated into phospholipids of germinating pollen and stimulated pollen tube growth. Our study provides evidence that pistil derived lipids contribute to membrane lipid synthesis in pollen tube growth, a hitherto unknown role in synergistic pollen-pistil interactions.
PubMed: 38917229
DOI: 10.1093/plphys/kiae276 -
PloS One 2024Land use change affects both pollinator and herbivore populations with consequences for crop production. Recent evidence also shows that land use change affects insect...
Land use change affects both pollinator and herbivore populations with consequences for crop production. Recent evidence also shows that land use change affects insect traits, with intraspecific body size of pollinators changing across landscape gradients. However, the consequences on crop production of trait changes in different plant interactors have not been well-studied. We hypothesized that changes in body size of key species can be enough to affect crop productivity, and therefore looked at how the field-realistic variation in body size of both an important pollinator, Bombus impatiens (Cresson), and a key pest herbivore, Lygus lineolaris (Palisot), can affect fruit size and damage in strawberry. First, we determined if pests vary in body size along land use gradients as prior studies have documented for pollinators; and second, we tested under controlled conditions how the individual and combined changes in size of an important pollinator and a key herbivore pest affect strawberry fruit production. The key herbivore pest was smaller in landscapes with more natural and semi-natural habitat, confirming that herbivore functional traits can vary along a land use gradient. Additionally, herbivore size, and not pollinator size, marginally affected fruit production-with plants exposed to larger pests producing smaller fruits. Our findings suggest that land use changes at the landscape level affect crop production not just through changes in the species diversity of insect communities that interact with the plant, but also through changes in body size traits.
Topics: Fragaria; Animals; Fruit; Body Size; Pollination; Herbivory; Bees
PubMed: 38917100
DOI: 10.1371/journal.pone.0305370 -
Annals of Botany Jun 2024Spatial variation in plant-pollinator interactions is a key driver of floral trait diversification. A so far overlooked qualitative aspect of this variation is the...
BACKGROUND AND AIMS
Spatial variation in plant-pollinator interactions is a key driver of floral trait diversification. A so far overlooked qualitative aspect of this variation is the behavioural component on flowers that relates to the pollinator fit. We tested the hypothesis that variation in pollinator behaviour influences the geographical pattern of phenotypic selection across the distribution range of the oil-producing Krameria grandiflora (Krameriaceae). This variation mainly involves the presence or absence of flag petal grasping, which is only performed by representatives of Centris (Centridini, Apidae), an oil-collecting bee group highly associated with Krameriaceae pollination.
METHODS
We quantified variation in floral traits and fitness and estimated pollinator-mediated selection in five populations at a large geographical scale comprising the entire species range. In each population, we sampled individual pollen arrival and germination as a fitness measure, indicating pollination success and pollination performance, which was then relativized and regressed on standardized flower-pollinator fit (flag-stigma distance), advertisement (sepal length) and reward (oil volume) traits. This generated mean-scaled selection gradients used to calculate geographical selection dispersion.
KEY RESULTS
Unexpectedly, stronger selection was detected on the flower-pollinator fit trait in populations highly associated to the absence of the flag petal grasping. Geographical variation in selection was mainly attributed to differential selection on the flag-stigma distance generating a selection mosaic. This may involve influences of a spatial variation in pollinator behaviour as well as composition and morphology.
CONCLUSIONS
Our results show the adaptive significance of the specialized "flag" petals of Krameria in the absence of the grasping behaviour and highlight the contribution of geographical variation in pollinator behaviour on flowers in driving selection mosaics, with implications for floral evolution, adaptation to pollinator fit and phenotypic diversity in specialized systems.
PubMed: 38916514
DOI: 10.1093/aob/mcae102 -
Plant Communications Jun 2024Transient heatwaves occur more frequently with climate warming, yet their impacts on crop yield are severely underestimated and even overlooked. Heatwaves spanning mere... (Review)
Review
Transient heatwaves occur more frequently with climate warming, yet their impacts on crop yield are severely underestimated and even overlooked. Heatwaves spanning mere days or even hours during sensitive stages (e.g., microgametogenesis and flowering) can significantly reduce crop yield by disrupting plant reproduction. Recently, advancements in multi-omics and GWAS analysis have shed light on specific organs (e.g., pollen, lodicule, and style), key metabolic pathways (sugar and reactive oxygen species (ROS) metabolisms, Ca homeostasis), and essential genes for transient heatwaves responses during the most sensitive stages in many crops. Based on this, this review places particular emphasis on the crop's heat-sensitive stages, using pollen development, floret opening, pollination, and fertilization as the central narrative thread. Complementing by key parts such as lodicule and tapetum, the multifaceted effects of transient heatwaves and their molecular basis are systematically demonstrated. A number of heat-tolerant genes for these processes have been identified in major crops such as maize and rice. The mechanisms and key heat-tolerant genes shared over different stages potentially facilitate the improvement of heat-tolerant crops more precisely.
PubMed: 38915200
DOI: 10.1016/j.xplc.2024.101009 -
Scientific Reports Jun 2024Haploid induction (HI) holds great promise in expediting the breeding process in onion, a biennial cross-pollinated crop. We used the CENH3-based genome elimination...
Haploid induction (HI) holds great promise in expediting the breeding process in onion, a biennial cross-pollinated crop. We used the CENH3-based genome elimination technique in producing a HI line in onion. Here, we downregulated AcCENH3 using the RNAi approach without complementation in five independent lines. Out of five events, only three could produce seeds upon selfing. The progenies showed poor seed set and segregation distortion, and we were unable to recover homozygous knockdown lines. The knockdown lines showed a decrease in accumulation of AcCENH3 transcript and protein in leaf tissue. The decrease in protein content in transgenic plants was correlated with poor seed set. When the heterozygous knockdown lines were crossed with wild-type plants, progenies showed HI by genome elimination of the parental chromosomes from AcCENH3 knockdown lines. The HI efficiency observed was between 0 and 4.63% in the three events, and it was the highest (4.63%) when E1 line was crossed with wildtype. Given the importance of doubled haploids in breeding programmes, the findings from our study are poised to significantly impact onion breeding.
Topics: Onions; RNA Interference; Plants, Genetically Modified; Haploidy; Plant Proteins; Gene Expression Regulation, Plant; Down-Regulation; Plant Breeding; Gene Knockdown Techniques
PubMed: 38914600
DOI: 10.1038/s41598-024-64432-7