The reproductive strategy of a pollinator-limited Himalayan plant, Incarvillea mairei (Bignoniaceae)

BACKGROUND: Plants may adapt to alpine habitats by specialization in the reproductive strategy and functional aspects of their flowers and pollination systems. Alpine habitats reduce the opportunities for cross-pollination in a relatively high proportion of alpine plant species, and self-pollination may be favored in these adverse conditions. Here, we investigated the mating system and pollination of Incarvillea mairei, a perennial Himalayan herb typically found at altitudes between 3000 and 4500 m. RESULTS: Analyses of floral morphology, observation of plant-pollinator interactions, and hand pollination experiments were conducted in three natural populations. Outcrossing rates and effective numbers of pollen donors were assessed in 45 open-pollinated families by using progeny analysis based on seven microsatellite markers. Incarvillea mairei displayed a set of apparently specialized floral traits, the stigma is sensitive to touch and close immediately and its reopening allows a second opportunity for the receipt of pollen. The species is fully self-compatible but employs a predominantly outcrossing mating system according to parentage analysis (t(m) > 0.9). Fruit set was low (26.3%), whereas seed set was high (67.2%), indicating that this species suffers pollinator limitation. Its main effective pollinator was Halictus sp., and visitation frequency was low. CONCLUSIONS: Floral features such as having a sensitive stigma and anther-prongs, in conjunction with pollinator behavior, function together contributing to a set of unique reproductive adaptations that enhance outcrossing success. The increased floral longevity and high pollination efficiency operated as compensatory mechanisms to counteract low pollinator visitation frequency

Trait variation and functional diversity maintenance of understory herbaceous species coexisting along an elevational gradient in Yulong Mountain, Southwest China

Characterizing trait variation across different ecological scales in plant communities has been viewed as a way to gain insights into the mechanisms driving species coexistence. However, little is known about how changes in intraspecific and interspecific traits across sites influence species richness and community assembly, especially in understory herbaceous communities. Here we partitioned the variance of four functional traits (maximum height, leaf thickness, leaf area and specific leaf area) across four nested biological scales: individual, species, plot, and elevation to quantify the scale-dependent distributions of understory herbaceous trait variance. We also integrated the comparison of the trait variance ratios to null models to investigate the effects of different ecological processes on community assembly and functional diversity along a 1200-m elevational gradient in Yulong Mountain. We found interspecific trait variation was the main trait variation component for leaf traits, although intraspecific trait variation ranged from 10% to 28% of total variation. In particular, maximum height exhibited high plasticity, and intraspecific variation accounted for 44% of the total variation. Despite the fact that species composition varied across elevation and species richness decreased dramatically along the elevational gradient, there was little variance at our largest (elevation) scale in leaf traits and functional diversity remained constant along the elevational gradient, indicating that traits responded to smaller scale influences. External filtering was only observed at high elevations. However, strong internal filtering was detected along the entire elevational gradient in understory herbaceous communities, possibly due to competition. Our results provide evidence that species coexistence in understory herbaceous communities might be structured by differential niche-assembled processes. This approach –– integrating different biological scales of trait variation –– may provide a better understanding of the mechanisms involved in the structure of communities

Noxa inhibits oncogenesis through ZNF519 in gastric cancer and is suppressed by hsa-miR-200b-3p

Abstract While Phorbol-12-myristate-13-acetate-induced protein 1 (Noxa/PMAIP1) assumes a pivotal role in numerous tumors, its clinical implications and underlying mechanisms of gastric cancer (GC) are yet enigmatic. In this investigation, our primary objective was to scrutinize the clinical relevance and potential mechanisms of Noxa in gastric cancer. Immunohistochemical analysis was conducted on tissue microarrays comprising samples from a meticulously characterized cohort of 84 gastric cancer patients, accompanied by follow-up data, to assess the expression of Noxa. Additionally, Noxa expression levels in gastric cancer clinical samples and cell lines were measured through quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis. The effect of Noxa expression on the prognosis of patients with gastric cancer was evaluated using Kaplan–Meier survival. Further insight into the role of Noxa in driving gastric cancer progression was gained through an array of experimental techniques, including cell viability assays (CCK8), plate cloning assays, transwell assays, scratch assays, and real-time cell analysis (RTCA). Potential upstream microRNAs (miRNAs) that might modulate Noxa were identified through rigorous bioinformatics analysis, substantiated by luciferase reporter assays and Western blot experiments. Additionally, we utilized RNA sequencing, qRT-PCR, and Western blot to identify proteins binding to Noxa and potential downstream target. Finally, we utilized BALB/c nude mice to explore the role of Noxa in vivo. Our investigation unveiled a marked downregulation of Noxa expression in gastric cancer and underscored its significance as a pivotal prognostic factor influencing overall survival (OS). Noxa overexpression exerted a substantial inhibitory effect on the proliferation, migration and invasion of GC cells. Bioinformatic analysis and dual luciferase reporter assays unveiled the capacity of hsa-miR-200b-3p to interact with the 3′-UTR of Noxa mRNA, thereby orchestrating a downregulation of Noxa expression in vitro, consequently promoting tumor progression in GC. Our transcriptome analysis, coupled with mechanistic validation, elucidated a role for Noxa in modulating the expression of ZNF519 in the Mitophagy-animal pathway. The depletion of ZNF519 effectively reversed the oncogenic attributes induced by Noxa. Upregulation of Noxa expression suppressed the tumorigenesis of GC in vivo. The current investigation sheds light on the pivotal role of the hsa-miR-200b-3p/Noxa/ZNF519 axis in elucidating the pathogenesis of gastric cancer, offering a promising avenue for targeted therapeutic interventions in the management of this challenging malignancy