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Our findings uncover the molecule framework controlling the polyp-to-jellyfish transition in a basal metazoan and provide insights into the evolution of complex life cycles in the animal kingdom.

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Understanding evolutionary interactions among crops and weeds can facilitate effective weed management. For example, gene flow from crops to their wild or weedy relatives can lead to rapid evolution in recipient populations. In rice (Oryza sativa), transgenic herbicide resistance is expected to spread to conspecific weedy rice (Oryza sativa f. spontanea) via hybridization.Here, we studied fitness effects of transgenic over-expression of a native 5-enolpyruvoylshikimate-3-phosphate synthase (epsps) gene developed to confer glyphosate resistance in rice. Controlling for genetic background, we examined physiological traits and field performance of crop–weed hybrid lineages that segregated for the presence or absence of this novel epsps transgene.Surprisingly, we found that transgenic F2 crop–weed hybrids produced 48–125% more seeds per plant than nontransgenic controls in monoculture- and mixed-planting designs without glyphosate application. Transgenic plants also had greater EPSPS protein levels, tryptophan concentrations, photosynthetic rates, and per cent seed germination compared with nontransgenic controls.Our findings suggest that over-expression of a native rice epsps gene can lead to fitness advantages, even without exposure to glyphosate. We hypothesize that over-expressed epsps may be useful to breeders and, if deployed, could result in fitness benefits in weedy relatives following transgene introgression.

Whole-genome duplication (WGD) events have occurred repeatedly during flowering plant evolution, and there is growing evidence for predictable patterns of gene retention and loss following polyploidization. Despite these important insights, the rate and processes governing the earliest stages of diploidization remain poorly understood, and the relative importance of genetic drift, positive selection, and relaxed purifying selection in the process of gene degeneration and loss is unclear. Here, we conduct whole-genome resequencing in Capsella bursa-pastoris, a recently formed tetraploid with one of the most widespread species distributions of any angiosperm. Whole-genome data provide strong support for recent hybrid origins of the tetraploid species within the past 100,000-300,000 y from two diploid progenitors in the Capsella genus. Major-effect inactivating mutations are frequent, but many were inherited from the parental species and show no evidence of being fixed by positive selection. Despite a lack of large-scale gene loss, we observe a decrease in the efficacy of natural selection genome-wide due to the combined effects of demography, selfing, and genome redundancy from WGD. Our results suggest that the earliest stages of diploidization are associated with quantitative genome-wide decreases in the strength and efficacy of selection rather than rapid gene loss, and that nonfunctionalization can receive a "head start" through a legacy of deleterious variants and differential expression originating in parental diploid populations.polyploidy | population genomics | speciation | gene loss

Summary Identification of seed development regulatory genes is the key for the genetic improvement in rice grain quality. NF ‐Ys are the important transcription factors, but their roles in rice grain quality control and the underlying molecular mechanism remain largely unknown. Here, we report the functional characterization a rice NF ‐Y heterotrimer complex NF ‐ YB 1‐ YC 12‐ bHLH 144, which is formed by the binding of NF ‐ YB 1 to NF ‐ YC 12 and then bHLH 144 in a sequential order. Knock‐out of each of the complex genes resulted in alteration of grain qualities in all the mutants as well as reduced grain size in crnf‐yb1 and crnf‐yc12 . RNA ‐seq analysis identified 1496 genes that were commonly regulated by NF ‐ YB 1 and NF ‐ YC 12 , including the key granule‐bound starch synthase gene Wx . NF ‐ YC 12 and bHLH 144 maintain NF ‐ YB 1 stability from the degradation mediated by ubiquitin/26S proteasome, while NF ‐ YB 1 directly binds to the ‘G‐box’ domain of Wx promoter and activates Wx transcription, hence to regulate rice grain quality. Finally, we revealed a novel grain quality regulatory pathway controlled by NF ‐ YB 1‐ YC 12‐ bHLH 144 complex, which has great potential for rice genetic improvement.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases. For decades, the unilateral 6-hydroxydopamine (6-OHDA) rat model has been employed to investigate the pathogenesis and therapy of PD. However, the behavior and associated pathological features of the model long term have not previously been described dynamically. In the present study, the unilateral model was established by 6-OHDA injection in the striatum. The PD rat model was determined 2 weeks following surgery, according to the apomorphine (APO)-induced rotations, cylinder, rotarod and open field tests. TH-positive neurons and fibers in the substantia nigra pars compacta (SNpc) and striatum, respectively, and glial activation in the SNpc, determined by glial fibrillary acidic protein (GFAP) expression for astrocytes and CD11b (Mac1) expression for microglia, were detected by immunohistological staining. Correlation analysis was performed to understand the association between PD-associated behavior and pathology. The behavioral impairment progressively deteriorated during the process of experiment. In addition, the decrease in TH-positive neurons was associated with an increase in GFAP- and Mac1-positive cells in the SNpc. Linear regression analysis indicated the association between behavioral and pathological changes. The results of the present study indicate that the APO-induced rotation, cylinder and rotarod tests are all sensitive and reliable strategies to predict the loss of TH+ neurons. These results provide a potential intervention time-point and a comprehensive evaluation index system for assessment of PD therapeutic strategies using the hemiparkinsonian rat.

BackgroundThe metagenesis of sessile polyps into pelagic medusae in cnidarians represents one of the most ancient complex life cycles in animals. Interestingly, scyphozoans and hydrozoans generate medusae by apparently fundamentally different processes. It is therefore unclear whether medusa formation has evolved independently in different medusozoans. To this end, a thorough understanding of the correspondence of polyp and medusa is required.ResultsWe monitored the expression patterns of conserved developmental genes in developing medusae of Clytia hemisphaerica (Hydrozoa) and Aurelia aurita (Scyphozoa) and found that developing medusae and polyps share similarities in their morphology and developmental gene expression. Unexpectedly, however, polyp tentacle marker genes were consistently expressed in the developing medusa bell, suggesting that the bell of medusae corresponds to modified and fused polyp tentacle anlagen.ConclusionsOur data represent the first comparative gene expression analysis of developing medusae in two representatives of Scyphozoa and Hydrozoa. The results challenge prevailing views about polyp medusa body plan homology. We propose that the evolution of a new life stage may be facilitated by the adoption of existing developmental genes.Electronic supplementary materialThe online version of this article (doi:10.1186/s13227-015-0017-3) contains supplementary material, which is available to authorized users.