Potato (
., family Solanaceae) is the most important noncereal food crop globally. It has over 100 wild relatives in the
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, which features species with both sexual and asexual reproduction and ...varying ploidy levels. A pangenome of
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composed of 296 accessions was constructed including diploids and polyploids compared via presence/absence variation (PAV). The
core (genes shared by at least 97% of the accessions) and shell genomes (shared by 3 to 97%) are enriched in basic molecular and cellular functions, while the cloud genome (genes present in less than 3% of the member accessions) showed enrichment in transposable elements (TEs). Comparison of PAV in domesticated vs. wild accessions was made, and a phylogenetic tree was constructed based on PAVs, grouping accessions into different clades, similar to previous phylogenies produced using DNA markers. A cladewise pangenome approach identified abiotic stress response among the core genes in clade 1+2 and clade 3, and flowering/tuberization among the core genes in clade 4. The TE content differed between the clades, with clade 1+2, which is composed of species from North and Central America with reproductive isolation from species in other clades, having much lower TE content compared to other clades. In contrast, accessions with in vitro propagation history were identified and found to have high levels of TEs. Results indicate a role for TEs in adaptation to new environments, both natural and artificial, for
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Numerous studies have assessed the detrimental effects of microplastics (MPs) on aquatic invertebrates due to their ubiquitous and persistent nature. In this study, the toxic effects of MPs were ...examined on the polyp and ephyrae of the marine hydrozoan Sanderia malayensis. The jellyfish were exposed to different sizes (1–6 μm) of non-functionalized polystyrene microbeads at a concentration of 1 × 104 particles mL−1. The MPs randomly attached to the external and internal parts of the jellyfish body, and the longest MP attachment was 52 days during the depuration after initial exposure (for 24 h). Consistent seventeen-day exposure to MPs significantly reduced the asexual reproduction of the S. malayensis polyps. To assess if the MPs can stimulate nematocyst discharge in polyp and ephyrae stages via direct contact, they were exposed to particle sizes up to 430 μm. None of the MPs or their aggregates, including the 430 μm particles, induced nematocyst discharge. These results suggest that prolonged exposure to relatively high MP concentrations affects the early stages of jellies and provides evidence for the no effect on nematocyst discharge.
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•MPs randomly attached to external and internal parts of the jellyfish body.•The longest MP attachment was 52 days during depuration after 24 h exposure.•17-Day exposure to MPs significantly reduced asexual reproduction of the polyps.•None of the MPs or their aggregates induced nematocyst discharge.
Flowering plants possess an unrivaled diversity of mechanisms for achieving sexual and asexual reproduction, often simultaneously. The commonest type of asexual reproduction is clonal growth ...(vegetative propagation) in which parental genotypes (genets) produce vegetative modules (ramets) that are capable of independent growth, reproduction, and often dispersal. Clonal growth leads to an expansion in the size of genets and increased fitness because large floral displays increase fertility and opportunities for outcrossing. Moreover, the clonal dispersal of vegetative propagules can assist “mate finding,” particularly in aquatic plants. However, there are ecological circumstances in which functional antagonism between sexual and asexual reproductive modes can negatively affect the fitness of clonal plants. Populations of heterostylous and dioecious species have a small number of mating groups (two or three), which should occur at equal frequency in equilibrium populations. Extensive clonal growth and vegetative dispersal can disrupt the functioning of these sexual polymorphisms, resulting in biased morph ratios and populations with a single mating group, with consequences for fertility and mating. In populations in which clonal propagation predominates, mutations reducing fertility may lead to sexual dysfunction and even the loss of sex. Recent evidence suggests that somatic mutations can play a significant role in influencing fitness in clonal plants and may also help explain the occurrence of genetic diversity in sterile clonal populations. Highly polymorphic genetic markers offer outstanding opportunities for gaining novel insights into functional interactions between sexual and clonal reproduction in flowering plants.
Inducing adventitious root (AR) formation in mature walnut species (Juglans L.) is challenging. However, the AR formation of mature trees can be improved by rejuvenation. In rejuvenated cuttings, ...exogenous indole-3-butyric acid (IBA) is essential for AR formation, and the underlying mechanism is still not well understood. Therefore, we utilized transcriptome sequencing to investigate the mechanism of IBA-induced AR formation. Our results revealed that, in comparison to the control group, IBA treatment (9 mM) significantly increased the endogenous indole-3-acetic acid (IAA) content, leading to an enhanced rooting rate. We performed RNA sequencing to identify differentially expressed genes (DEGs) between the IBA-treated and control (CK) groups at 1, 2, 3, and 5 days after cutting (DAC). The results showed that, compared to the control cuttings, there were 1 539, 889, 785, and 984 up-regulated genes and 2 791, 2 936, 3 017, and 1 752 down-regulated genes, at 1, 2, 3, and 5 DAC, respectively. Analysis of RNA-seq data revealed that G-type ATP-binding cassette 36/37 (ABCG36/37) and ATP-binding cassette subfamily D 1 (ABCD1), associated with IBA transport, were down-regulated in the rejuvenation cuttings. In contrast, PIN-FORMED (PIN) and PINOID (PID), associated with auxin efflux, were up-regulated. We identified 49 auxin/indole-3-acetic acid (AUX/IAA)-encoding genes, including IAA1, IAA3, IAA5, IAA6, IAA8, IAA11, IAA12, IAA19, and IAA20, which were up-regulated at 1–5 DAC in the rejuvenated cuttings. This study highlights that the overexpression of JrWOX5/11 in poplar significantly enhance AR growth, as evidenced by increased root length, surface area, volume, and quantity. Moreover, the co-expression network analysis involving JrWOX11 and JrWOX5 in walnut cuttings elucidates complex genetic interactions, underscoring their pivotal role in the formation of AR. Our data supported the following molecular mechanism of IBA-induced adventitious root formation. Firstly, IBA is converted to free IAA in peroxisomes. Then, the highly concentrated IAA in the procambium and parenchyma cells induces WUSCHEL-related homeobox 11 (WOX11) expression at 2 days. Finally, WOX11 acts redundantly to up-regulate WOX5, initiating the development of root primordia cells.
The histological origin of podocysts in scyphozoans has long been undetermined, with uncertainty whether they arise from mesenchymal amoebocytes or stalk and pedal disc ectoderm in polyps. ...Histological investigation on the pedal disc was difficult due to the settlement of polyps on hard substrates. In this study, we investigated the histological characteristics of polyps during podocyst production in Asian moon jelly (Aurelia coerulea) with utilizing those attached on thin polystyrene substrates. Fine histological features of the pedal disc became possible after the substrates were decomposed during histological processing. Our findings unequivocally demonstrate that the cell mass of podocysts originates from the ectoderm of the pedal disc and the stalk without the involvement of amoebocytes in the mesoglea. Preceding the podocyst formation, the pedal disc undergoes enlargement facilitated by the elongated stalk ectodermal cells, which attach to a substrate. Subsequently, the pedal disc ectoderm give rise to the primary podocyst cells with accumulating nutrient granules in the cytoplasm and forming the cyst capsule cooperatively with the invaginated pedal disc ectoderm. Direct transformation from the ectodermal cells to podocyst cells suggests that podocyst formation involves tissue dedifferentiation. Throughout the period of podocyst production, the gastrodermis of polyps is physically separated from the ectoderm by the mesoglea and shows no histological changes, and no amoebocytes appear in the mesoglea. These histological properties are totally different from those in other modes of asexual reproduction, which incorporate the endoderm of polyps, suggesting the developmental and evolutionary differences between these asexual reproductions and podocyst production in Scyphozoa.
The podocyst of Aurelia coerulea is derived exclusively from the ectoderm in the pedal disc and stalk of polyps. The pedal disc of the polyp expands with the involvement of stalk ectodermal cells, and the pedal disc ectoderm then invaginates to form a cyst capsule and nutrient granules and undergoes dedifferentiation. Finally, these cells are radially arranged with the formation of extracellular matrix and closure of the capsule to become a podocyst.
Abstract
The reproductive strategy of planktonic foraminifera, key pelagic calcifiers, has long remained elusive, hampering efforts to understand and model their population dynamics. This is ...particularly critical in polar oceans where their success relies on rapid population growth after the polar night. Here, we provide field and laboratory observations constraining the reproductive cycle of the dominant polar species Neogloboquadrina pachyderma in Antarctic and Arctic waters. We observe that asexual reproduction is a rare but persistent element of the reproductive strategy and that it is reflected in a dimorphism in proloculus and in the ratio of shell size versus the number of chambers between sexually and asexually produced individuals. This dimorphism in natural populations reveals that asexual reproduction supplies more than 75% of adult individuals. This indicates a multigenerational reproduction strategy, where the majority of the population releases gametes to facilitate recombination, while a minority persistently reproduces asexually, allowing rapid population growth as a prerequisite for success in the polar oceans.
•The POA algorithm mimics the sexual and asexual propagation mechanism of poplar.•The performance of POA is tested on two test suites with different features.•POA is used to find optimal thresholds ...for image segmentation.•The results indicate that POA is competitive and has its superiority in some cases.
A novel algorithm called Poplar Optimization Algorithm (POA) is developed in this paper to solve continuous optimization problems. The algorithm mimics the sexual and asexual propagation mechanism of poplar, where the basic philosophy of how to execute sexual and asexual propagation for individuals is detail designed in the algorithm. Mutation strategy of backtracking search algorithm is adopted in POA to maintain the diversity in a certain degree. The performance of POA algorithm is tested on 25 functions from the CEC2005 test suite and 30 functions from the CEC2017 test suite with different features. The results of POA are compared with some other population-based algorithms in terms of the quality and efficiency. Finally, the proposed algorithm is used to find the optimal threshold for image segmentation. The results indicate that the poplar optimization algorithm can obtain competitive or superior performance.
Cnidarians exhibit various patterns of asexual reproduction. Pedal lacerations have been reported in corallimorpharians and sea anemones. Here, I report the occurrence of pedal lacerations in two ...colonies of octocoral Sarcophyton sp. (order Alcyonacea). The lacerated conical pedal tissue gradually regenerated new buds in both the colonies. Two possible causes of pedal lacerations were considered. First, both the colonies may have moved to elevated positions to access light for photosynthesis. Second, both colonies were unstable owing to the movement of the rubble by the current pump and moved to a stable place.
•R. subcapitata present palmelloid-like phenotype in presence of pollutants.•Palmelloid phenotype is characterized by multinucleated cells and lipids accumulation.•Palmelloid formation is dependent ...on pollutant, its concentration and exposure time.•Palmelloid is a transitory state being reverted to a single-nucleus state after stress release.•Palmelloid phenotype is not a generalized defense response against stress.
This work focuses on the formation of palmelloid-like phenotype in the freshwater alga Raphidocelis subcapitata (formerly known as Pseudokirchneriella subcapitata and Selenastrum capricornutum), when exposed to adverse conditions generated by the presence of organic the antibiotic erythromycin (ERY) and the herbicide metolachlor (MET) or inorganic the heavy metals, cadmium (Cd) and zinc (Zn) pollutants, at environmentally relevant concentrations. This alga in absence of stress or when exposed to ERY or Zn, up to 200 µg/L, essentially showed a single-nucleus state, although algal growth was reduced or stopped. R. subcapitata “switched” to a multinucleated state (palmelloid-like morphology) and accumulated energy-reserve compounds (neutral lipids) when stressed by 100–200 µg/L MET or 200 µg/L Cd; at these concentrations of pollutants, growth was arrested, however, the majority of the algal population (≥83 %) was alive. The formation of palmelloid-like phenotype, at sub-lethal concentrations of pollutants, was dependent on the pollutant, its concentration and exposure time. The multinucleated structure is a transitory phenotype since R. subcapitata population was able to revert to a single-nucleus state, with normal cell size, within 24–96 h (depending on the impact of the toxic in the alga), after being transferred to fresh OECD medium, without pollutants. The obtained results indicate that the formation of a palmelloid-like phenotype in R. subcapitata is dependent on the mode of action of toxics and their concentration, not constituting a generalized defense mechanism against stress. The observations here shown contribute to understanding the different strategies used by the unicellular alga R. subcapitata to cope with severe stress imposed by organic and inorganic pollutants.
Endosymbiotic bacteria can induce parthenogenesis in many haplo-diploid species, but little is known about their role in asexual reproduction in diplodiploids. Bacteria are essential for reproduction ...in the asexual lineages of springtails and booklice, and possibly some weevils, but whether they are the causative agent of parthenogenesis remains to be proven. This would require comparing unisexual forms and their closely related bisexual species, but such model species are very rare. Empoasca leafhoppers from the Madeira Archipelago provide an excellent case to test whether bacterial infections can cause parthenogenesis. Here we examined the diversity of the sex-distorting bacteria, Wolbachia, Cardinium, Rickettsia, and Arsenophonus, in three apomictic morphotypes (A, B, C) and three bisexual relatives of Empoasca. Wolbachia of group B was present in all unisexual and bisexual species. Rickettsia were the only bacteria restricted to the three unisexual forms, suggesting an association between infection and asexual reproduction. In addition, we found Asaia for the third time in the Cicadellidae, although this may have little to do with the reproductive mode of its host. Adult females of morphotype C reared on plants watered with tetracycline solution did not result in the production of male offspring. To our knowledge, this is the first study to suggest a possible association between bacterial infection and parthenogenesis in apomictic XO/XX diplodiploid bisexual species based on a range of sex ratio-distorting bacteria.
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