Reproductive Progeny Research Articles

Resistance to both aphids and nematodes in tobacco plants expressing a Bacillus thuringiensis crystal protein.

Bacillus thuringiensis (Bt) and its crystal toxin or δ-endotoxins (Cry) offer great potential for the efficient control of crop pests. A vast number of pests can potentially infect the same host plant, either simultaneously or sequentially. However, no effective Bt-Cry protein has been reported to control both aphids and plant parasitic nematodes due to its highly specific activity. Our study indicated that the Cry5Ba2 protein was toxic to the green peach aphid Myzus persicae, which had a median lethal concentration (LC50) of 9.7 ng μL-1 and fiducial limits of 3.1-34.6 ng μL-1. Immunohistochemical localization of Cry5Ba2 revealed that it could bind to the apical tip of microvilli in midgut regions. Moreover, transgenic tobacco plants expressing Cry5Ba2 exhibited significant resistance to Myzus persicae, as evidenced by reduced insect survival and impaired fecundity, and also intoxicated the Meloidogyne incognita as indicated by a decrease in galls and progeny reproduction. In sum, we identified a new aphicidal Bt toxin resource that could simultaneously control both aboveground and belowground pests, thus extending the application range of Bt-based strategy for crop protection. © 2024 Society of Chemical Industry.

Viral community-wide auxiliary metabolic genes differ by lifestyles, habitats, and hosts

BackgroundViral-encoded auxiliary metabolic genes (AMGs) are important toolkits for modulating their hosts’ metabolisms and the microbial-driven biogeochemical cycles. Although the functions of AMGs have been extensively reported in numerous environments, we still know little about the drivers that shape the viral community-wide AMG compositions in natural ecosystems. Exploring the drivers of viral community-wide AMG compositions is critical for a deeper understanding of the complex interplays among viruses, hosts, and the environments.ResultsHere, we investigated the impact of viral lifestyles (i.e., lytic and lysogenic), habitats (i.e., water, particle, and sediment), and prokaryotic hosts on viral AMG profiles by utilizing metagenomic and metatranscriptomic techniques. We found that viral lifestyles were the most important drivers, followed by habitats and host identities. Specifically, irrespective of what habitats viruses came from, lytic viruses exhibited greater AMG diversity and tended to encode AMGs for chaperone biosynthesis, signaling proteins, and lipid metabolism, which could boost progeny reproduction, whereas temperate viruses were apt to encode AMGs for host survivability. Moreover, the lytic and temperate viral communities tended to mediate the microbial-driven biogeochemical cycles, especially nitrogen metabolism, in different manners via AMGs. When focusing on each lifestyle, we further found clear dissimilarity in AMG compositions between water and sediment, as well the divergent AMGs encoded by viruses infecting different host orders.ConclusionsOverall, our study provides a first systematic characterization of the drivers of viral community-wide AMG compositions and further expands our knowledge of the distinct interactions of lytic and temperate viruses with their prokaryotic hosts from an AMG perspective, which is critical for understanding virus-host-environment interactions in natural conditions.-i-eSMHy56EjkBsNfneT5sVideo

Optimizing RNAi-Target by Nicotiana benthamiana-Soybean Mosaic Virus System Drives Broad Resistance to Soybean Mosaic Virus in Soybean.

Soybean mosaic virus (SMV) is a prevalent pathogen of soybean (Glycine max). Pyramiding multiple SMV-resistance genes into one individual is tedious and difficult, and even if successful, the obtained multiple resistance might be broken by pathogen mutation, while targeting viral genome via host-induced gene silencing (HIGS) has potential to explore broad-spectrum resistance (BSR) to SMV. We identified five conserved target fragments (CTFs) from S1 to S5 using multiple sequence alignment of 30 SMV genome sequences and assembled the corresponding target-inverted-repeat constructs (TIRs) from S1-TIR to S5-TIR. Since the inefficiency of soybean genetic transformation hinders the function verification of batch TIRs in SMV-resistance, the Nicotiana benthamiana-chimeric-SMV and N. benthamiana-pSMV-GUS pathosystems combined with Agrobacterium-mediated transient expression assays were invented and used to test the efficacy of these TIRs. From that, S1-TIR assembled from 462 bp CTF-S1 with 92% conservation rate performed its best on inhibiting SMV multiplication. Accordingly, S1-TIR was transformed into SMV-susceptible soybean NN1138-2, the resistant-healthy transgenic T1-plants were then picked out via detached-leaf inoculation assay with the stock-plants continued for progeny reproduction (T1 dual-utilization). All the four T3 transgenic progenies showed immunity to all the inoculated 11 SMV strains under individual or mixed inoculation, achieving a strong BSR. Thus, optimizing target for HIGS via transient N. benthamiana-chimeric-SMV and N. benthamiana-pSMV-GUS assays is crucial to drive robust resistance to SMV in soybean and the transgenic S1-TIR-lines will be a potential breeding source for SMV control in field.

The results of cherry species (Prunus L.) alien pollination in connection with the possibility of agamosperm reproduction

Agamosperm (asexual) reproduction, along with conventional sexual reproduction, is quite widespread inthe Rosaceae Juss. family. It provides several advantages for successful seed progeny reproduction in unfavorable natural conditions. Remote hybridization and polyploidy are genetic mechanisms, which favor to the development of seedswithout fertilization. For species of stone plants, in the phylogeny of which these two factors play a decisive role, it is important to assess the possibility of the presence of a pseudogamous type of apomixes, which requires the obligatory pollenapplication on the stigma for seed development. The aim of the investigation was to study the results of alien pollinationfor 4 wild and cultivated cherries (Prunus pensylvanica L., P. maackii Rupr., P. fruticosa Pall., P. cerasus L.) in connection with the prospect of including the agamosperm genotypes in breeding crosses. The possibility of pseudogamous reproduction was revealed only for wild P. fruticosa.

Quantitative analysis of PAH compounds in DWH crude oil and their effects on Caenorhabditis elegans germ cell apoptosis, associated with CYP450s upregulation

The Deepwater Horizon (DWH) oil spill marked the largest environmental oil spill in human history, where it was estimated a large amount of the polycyclic aromatic hydrocarbons (PAHs) were released with crude oil into the environment. In this study, common PAH compounds were quantitatively determined in crude oil from the DWH spill by gas chromatography-mass spectroscopy (GC–MS). Twelve PAH compounds were identified and quantified from a 100× dilution of DWH crude oil: naphthalene (7800 ng/mL), acenaphthylene (590 ng/mL), acenaphtehen (540 ng/mL), fluorene (2550 ng/mL), phenanthrene (2910 ng/mL), anthracene (840 ng/mL), fluoranthene (490 ng/mL), pyrene (290 ng/mL), benzo(k) fluoranthene (1050 ng/mL), benzo(b)fluoranthene (1360 ng/mL), dibenz(a,h)anthracene (2560 ng/mL), and benzo(g, h, i) perylene (630 ng/mL). Toxicity assays using the nematode, Caenorhabditis elegans (C. elegans), indicated a single PAH compound naphthalene, exposure increased C. elegans germ cell apoptosis which may adversely affect progeny reproduction. The number of apoptotic germ cells significantly increased from 1.4 to 2.5 when worms were treated with 10 μg/mL of naphthalene and from 1.3 to 2.5 and 3.5 cells in presence of 1 μg/mL and 5 μg/mL of benzo(a)pyrene, respectively. Five CYP450 genes (CYP14A3, CYP35A1, CYP35A2, CYP35A5, and CYP35C1) were significantly upregulated following 500× dilution of dispersed crude oil exposure (p < 0.05). These results suggest that CYP450s may play a role in bioactivation of PAHs in crude oil, resulting in DNA damage related germ cell apoptosis.

Влияние экзогенного 20-гидроксиэкдизона и S-аденозилметионина на транскрипционную активность гена рецептора экдизона EcR у комнатной мухи Musca domestica L.

Steroid hormone 20-hydroxyecdysone (20E) initiates larval molting start and metamorphosis and regulates reproduction. Its basic receptor is heterodimer including proteins EcR and USP. Ecdysone receptor gene EcR coding protein EcR is a key regulatory element of gene circuits cover considerable part of genes, implicated in growth and development as well as in reproduction of progeny and reactions of organisms to unfavorable factors of environment. The source of methyl groups S-adenosylmethionine (SAM) is in use for biosynthesis of juvenile hormone (JH), methylation of histone proteins and DNA. The main aim of our investigation was evaluation of transcriptional activity of housefly Musca domestica ecdysone receptor gene EcR under adding into ration of 20E and SAM in non-lethal concentrations. Experiments were carried out with larvae and adults of housefly from laboratory strains Shgen and Lgen differ in life span of adults. Change of gene EcR transcripts content in common pool of mRNA in the cells of muscles and gonads, as well as DNA methylation level in 5’-terminal site registered by quantitative real time PCR (RT-PCR). The results of our investigations allow us to suggest existence of mechanism for regulating expression of the EcR gene in M. domestica which is sensitive to exogenic20E and heat stress action as well as to presence of SAM in food. Variations in the mRNA quantitative ratios of EcR gene 5’-and 3’-terminal regions depending on tissue type, gender and age support the hypothesis that this gene can encode several isoforms of the protein EcR. The detected changes in the status of DNA methylation in the 5'-terminal region of the gene and fluctuations in the representation of different mRNA sites after SAM processing suggest the involvement of DNA methylation/demethylation processes in the regulation of EcR gene expression in M. domestica.

Assessing fitness parameters of hybrids between weed beets and transgenic sugar beets

AbstractHerbicide resistance is a desired trait for sugar beet (Beta vulgaris L.) production because it is a low‐competitor crop that requires careful weed management. However, gene flow to weed beet (also B. vulgaris) could jeopardize the weed control strategy by causing the emergence of resistant weed beets; it could also lead to further adaptation of weed beet as a troublesome weed for other crops by selecting more competitive plants. To evaluate the hazard that such a selection process represents, apart the herbicide resistance, we investigated the morphology and reproduction of progeny of weed beets having inherited a herbicide resistance gene. First‐generation resistant weed beet exhibited traits likely counter‐selected. But such crop traits rapidly disappeared with backcrossing to weedy relatives: no biologically relevant difference was noted between resistant and susceptible near‐isogenic siblings in the various experiments. In the absence of resistance selection, our data indicate low chances for weed beet to evolve more competitive forms than present weed beet populations. However, they also suggest that there is no fitness cost limiting transgenes spread.

Fitness consequences of short‐ and long‐distance pollinations in Phlox hirsuta, an endangered species

The persistence of rare and endangered plant species may depend on the distance pollinators travel when dispersing pollen. Pollinations between adjacent plants, which are often genetically similar, can decrease seed set, germination, and/or progeny vigor due to shared S-alleles or inbreeding depression. Interpopulation pollen dispersal is often suggested as a management tool to increase genetic diversity; however, long-distance pollinations also have the potential to decrease fitness. We performed experimental hand pollinations in the field and germination experiments in a growth chamber to determine the effect of intrapopulation pollination distance (1 m, 10 m, and 100 m) on seed set, seed germination, progeny growth, and progeny reproduction in Phlox hirsuta. In addition, we included interpopulation pollinations (6740 m) to determine whether artificial gene flow is a viable management option for this endangered species. Although pollination distance did not affect the number of healthy seeds produced or the likelihood of radicle emergence, it did significantly affect the ability of germinating seeds to successfully produce cotyledons. Outbreeding depression was observed during seed germination and early seedling development. Seedlings resulting from interpopulation pollinations developed more slowly and were less likely to survive to produce cotyledons than seedlings resulting from all three intrapopulation pollination distances. Our results suggest that the success of P. hirsuta does not depend on the distance pollinators travel within populations and that conservation strategies that involve transporting genes between populations can be counterproductive.

All eggs are not equal: the maternal environment affects progeny reproduction and developmental fate in Caenorhabditis elegans.

BackgroundMaternal effects on progeny traits are common and these can profoundly alter progeny life history. Maternal effects can be adaptive, representing attempts to appropriately match offspring phenotype to the expected environment and are often mediated via trade-offs between progeny number and quality. Here we have investigated the effect of maternal food availability on progeny life history in the free-living nematode Caenorhabditis elegans.Methodology/Principal FindingsThe maternal environment affects both reproductive traits and progeny development. Comparisons of the progeny of worms from high and low maternal food environments indicates that low maternal food availability reduces progeny reproduction in good environments, increases progeny reproduction in poor environments and decreases the likelihood that progeny will develop as dauer larvae. These analyses also indicate that the effects on progeny are not a simple consequence of changes in maternal body size, but are associated with an increase in the size of eggs produced by worms at low maternal food availabilities.Conclusions/SignificanceThese results indicate that the maternal environment affects both progeny reproduction and development in C. elegans and therefore that all progeny are not equal. The observed effects are consistent with changes to egg provisioning, which are beneficial in harsh environments, and of changes to progeny development, which are beneficial in harsh environments and detrimental in benign environments. These changes in progeny life history suggest that mothers in poor quality environments may be producing larger eggs that are better suited to poor conditions.

Reproductive Potential of Overwintering, F&lt;SUB&gt;1&lt;/SUB&gt;, and F&lt;SUB&gt;2&lt;/SUB&gt; Female Boll Weevils (Coleoptera: Curculionidae) in the Lower Rio Grande Valley of Texas

The feeding and oviposition activity of overwintering boll weevils, Anthonomus grandis grandis (Boheman), and seasonal fluctuations in development, survival, and reproduction of progeny of overwintering and first- and second-generation boll weevil females were determined in the laboratory at 27 degrees C, 65% RH, and a photoperiod of 12:12 (L:D) h. During the cotton-free period in the Lower Rio Grande Valley, female boll weevils without access to cotton resorb their unlaid eggs and enter reproductive diapause. However, when they were provided daily with greenhouse-grown cotton squares, commencement of oviposition began after 7, 15, or 20 d, depending on when they were captured. Females captured later in the winter fed longer before laying eggs than those captured in the early fall, suggesting that it may take females longer to terminate diapause the longer they have been dormant. The rate of feeding by females was significantly less during the winter months, and this may have affected the rate of diet-mediated termination of dormancy. Females of the first and second generations after the overwintering generation produced a significantly higher percentage of progeny surviving to adulthood and a higher proportion of these progeny were females. Offspring development time from overwintering female parents was significantly longer than that from first and second generations under the same laboratory conditions. The total number of lifetime eggs produced by females of the second generation during the cotton-growing season were approximately 9.9-fold higher than for overwintering females and 1.5-fold higher than for first-generation females. Life table calculations indicated that the population of second-generation boll weevils increased an average of 1.5-fold higher each generation than for females of the first generation and 22.6-fold higher than for overwintering females. Our data showed variation in boll weevil survival, development, and reproductive potential among the overwintering and first- and second-generation females, suggesting inherent seasonal fluctuations in these parameters.

A NEW SPECIES OF METAPOLYBIA DUCKE FROM CENTRAL AMERICA (HYMENOPTERA: VESPIDAE; POLISTINAE)

A new species of the paper wasp genus Metapolybia Ducke is described, and its similarities to other species of the genus are discussed. Metapolybia Ducke is a small genus of neotropical paper wasps in the tribe Epi- ponini of the subfamily Polistinae, The tribe is of interest for its behavior of founding colonies by swarms of multiple queens accompanied by workers, and the genus is of interest because the phenomenon of cyclical oligogyny. West-Eberhard (1978), studying Metapolybia aztecoides Richards, observed that, although the swarm initi- ating a colony began with multiple egg-layers, only one egg-layer remained by the time that reproductive progeny were produced. This type of colony cycle, termed cyclical oligogyny by Strassmann et al. (1991), is considered to be important in the maintenance of eusociality in swarm-founding wasps, by raising relatedness among queens.

Apomixix in tropical fodder crops: cytological and functional aspects

The development of new approaches to improve breeding efficiency of tropical forage grasses is of great importance. The most recently developed techniques to study the type of apomixis and to establish the modes of reproduction in progeny of apomictic plants i.e.: callose deposition test, clearling methods, intact embryo sac analysis, flow cytometry, molecular approaches and the methods of classiacal light and transmission electron microscopy are described and discussed. Cytological and functional aspects of apospory with following aposporous parthenogenesis, and diplospory in grasses are highlighted.

Effects of Maternal Nutrient Pulse on Reproduction of Two Colonizing Plantago Species

Plantago major and P. rugelii maternal plants were grown at two background nutrient levels and received nutrient pulses given at different times during their life—span. The influences of these maternal treatments on the reproduction of progeny were examined in four different progeny environments represented by two treatments: with and without competition, and with and without a nutrient pulse. We found that the effects of maternal nutrient pulses on the two species were related to the environments of both parents and progeny. When grown without competition, progeny from parent P. major plants maintained at the low background nutrient level and given a nutrient pulse had a higher spike biomass and a higher proportional allocation to spikes than did progeny from parents that did not receive a nutrient pulse. In contrast, the progeny of parents that were maintained at the high nutrient level showed no response to a nutrient pulse. In P. rugelii the effect of maternal nutrient pulses on the total and leaf biomass of the progeny was related to both maternal background nutrient levels and nutrient pulse treatments to the progeny. For both species, the timing of maternal nutrient pulses had no significant effect on the characters studied. In competition, for P. major, the progeny from parents given a nutrient pulse during fruit maturation consistently produced a greater amount of spike biomass relative to their neighboring plants from parents that did not receive nutrient pulses, regardless of both the maternal background nutrients and progeny pulse treatments. However, for the progeny from parents given a nutrient pulse during the vegetative and flowering stages, their competitive ability relative to their neighbors depended on both the timing of maternal pulse and the progeny pulse treatment. For P. rugelii, the performance (leaf biomass) of the two neighboring progeny depended on maternal background nutrient levels. These results show that maternal nutrient, conditions can influence competitive interactions in the progeny generation. The effects may have ecological and evolutionary implications particularly for initial colonization of infertile sites and for the ability of natural selection to act on phenotypic variation. The strength of these maternal effects depends on both the maternal environment and the progeny environment.

Evolution of sex ratios in social hymenoptera: Consequences of finite brood size

Evolutionarily stable sex ratios are determined for social hymenoptera under local mate competition (LMC) and when the brood size is finite. LMC is modelled by the parameterd. Of the reproductive progeny from a single foundress nest, a fractiond disperses (outbreeding), while (l-d) mate amongst themselves (sibmating). When the brood size is finite,d is taken to be the probability of an offspring dispersing, and similarly,r, the proportion of male offspring, the probability of a haploid egg being laid. Under the joint influence of these two stochastic processes, there is a nonzero probability that some females remain unmated in the nest. As a result, the optimal proportion of males (corresponding to the evolutionarily stable strategy, ESS) is higher than that obtained when the brood size is infinite. When the queen controls the sex ratio, the ESS becomes more female biased under increased inbreeding (lowerd). However, the ESS under worker control shows an unexpected pattern, including anincrease in the proportion ofmales withincreased inbreeding. This effect is traced to the complex interaction between inbreeding and local mate competition.

Survival, Growth, and Reproduction of Progeny Isolated from High and Low Density Populations of Microtus montanus

The demographic consequences of lactational deficiency, which has been hypothesized to occur during periods of physiological stress in mammals, were assessed in Microtus montanus populations under field conditions. Comparisons are made among progeny of animals in an expanding population (= U cohort), juvenile progeny removed from high-density populations and introduced with (= M cohort) and without (= I cohort) previously crowded adults, and offspring (= F1 cohort) of voles of the I cohort. Survival rate of the I cohort was higher than the M cohort. Furthermore, males of the I cohort had a significantly higher instantaneous growth rate than the M cohort. The growth rates of females in the M and I cohorts were uniformly low. Sexual maturity was delayed in males of the M and I cohorts, though the delays were not sufficient to reduce the reproductive output. There was no significant difference in the proportions of either pregnant females or reproductive activity among cohorts. Early juvenile survival was high in the populations in which the U and I cohorts resided, whereas no juveniles survived in the M cohort's population. The observed changes in demographic parameters among the cohorts do not conform to the predictions of the lactational deficiency hypothesis. Survival and age at sexual maturity were primarily affected by seasonality, whereas individual growth, early juvenile survival, and population growth were primarily affected by adult-progeny social interactions.