26 research outputs found

    Commonness, rarity, and intraspecific variation in traits and performance in tropical tree seedlings

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    Abstract One of the few rules in ecology is that communities are composed of many rare and few common species. Trait-based investigations of abundance distributions have generally focused on speciesmean trait values with mixed success. Here, using large tropical tree seedling datasets in China and Puerto Rico, we take an alternative approach that considers the magnitude of intraspecific variation in traits and growth as it relates to species abundance. We find that common species are less variable in their traits and growth. Common species also occupy core positions within community trait space indicating that they are finely tuned for the available conditions. Rare species are functionally peripheral and are likely transients struggling for success in the given environment. The work highlights the importance of considering intraspecific variation in trait-based ecology and demonstrates asymmetry in the magnitude of intraspecific variation among species is critical for understanding of how traits are related to abundance

    Lack of phylogenetic signals within environmental niches of tropical tree species across life stages

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    The lasting imprint of phylogenetic history on current day ecological patterns has long intrigued biologists. Over the past decade ecologists have increasingly sought to quantify phylogenetic signals in environmental niche preferences and, especially, traits to help uncover the mechanisms driving plant community assembly. However, relatively little is known about how phylogenetic patterns in environmental niches and traits compare, leaving significant uncertainty about the ecological implications of trait-based analyses. We examined phylogenetic signals within known environmental niches of 64 species, at seedling and adult life stages, in a Chinese tropical forest, to test whether local environmental niches had consistent relationships with phylogenies. Our analyses show that local environmental niches are highly phylogenetically labile for both seedlings and adult trees, with closely related species occupying niches that are no more similar than expected by random chance. These findings contrast with previous trait-based studies in the same forest, suggesting that phylogenetic signals in traits might not a reliable guide to niche preferences or, therefore, to community assembly processes in some ecosystems, like the tropical seasonal rainforest in this study

    Meta-Analysis Results on the Association Between TP53 Codon 72 Polymorphism With the Susceptibility to Oral Cancer

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    Objectives: TP53 is an important tumor suppressor gene to maintain genomic integrity, and its mutations increase the susceptibility to oral carcinoma. Previous published studies have reported the relation of TP53 codon 72 polymorphism with the risk of oral carcinoma, but the results remain controversial and inconclusive.Methods: We therefore utilized meta-analysis based on a comprehensive search in PubMed, EMBASE, and Google of Scholar databases up to August 19, 2017.Results: Total 3,525 cases and 3,712 controls from 21 case-control studies were selected. We found no significant association between TP53 codon 72 polymorphism and oral carcinoma susceptibility in all genetic contrast models, including subgroup analysis based on control source and ethnicity. Furthermore, TP53 codon 72 polymorphism was not significant associated with oral carcinoma susceptibility in tobacco or alcohol use, and HPV infection status. Our results were confirmed by sensitivity analysis and no publication bias was found.Conclusions: Taken together, our data indicate that TP53 codon 72 polymorphism is not associated with the susceptibility to oral carcinoma

    Identification of the Genome-Wide Expression Patterns of Non-Coding RNAs Associated with Tanshinones Synthesis Pathway in Salvia miltiorrhiza

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    The red root of Salvia miltiorrhiza Bunge, a famous traditional Chinese medicine (TCM), was caused by tanshinone in epidermis cells. In order to study the biological function of ncRNAs in the tanshinone synthesis, the expression patterns of mRNA and ncRNAs were comprehensively analyzed in red (high tanshinone content) and white root (low tanshinone content) tissues derived from the same plant. A total of 731 differentially expressed genes (DEGs) were mainly enriched in primary metabolic pathways such as galactose and nitrogen, and some secondary metabolic pathways such as phenylpropanoid and terpenoids. A total of 70 miRNAs, 48 lncRNAs, and 26 circRNAs were identified as differentially expressed (DE) ones. The enrichment pathway of the targets of DE-lncRNA were mainly in ribosome, carbon metabolism, plant hormone signal transduction, and glycerophospholipid metabolism. The function of the targets genes of 59 miRNAs combined with DE-circRNAs was mainly involved in plant–pathogen interaction, endocytosis, phenylpropanoid biosynthesis, and sesquiterpenoid and triterpenoid biosynthesis pathways. Most genes of the tanshinone synthesis pathway had a higher expression. Some ncRNAs were predicted to regulate several key enzyme genes of the tanshinone synthesis pathway, such as SmDXS2, SmGGPPS1, SmKSL. Furthermore, most target genes were related to the resistance of pathogens. The present study exhibited the tissue-specific expression patterns of ncRNAs, which would provide a basis for further research into the regulation mechanism of ncRNAs in the tanshinone synthesis process

    Spatiotemporal and Transcriptional Characterization on Tanshinone Initial Synthesis in Salvia miltiorrhiza Roots

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    Tanshinones are the bioactive constituents of Danshen (Salvia miltiorrhiza Bunge), which is used in Traditional Chinese Medicine to treat cardiovascular and other diseases, and they synthesize and accumulate in the root periderm of S. miltiorrhiza. However, there is no relevant report on the initial stage of tanshinone synthesis, as well as the root structure and gene expression characteristics. The present study aims to provide new insights into how these bioactive principles begin to synthesize by characterizing possible differences in their biosynthesis and accumulation during early root development from both spatial and temporal aspects. The morphological characteristics and the content of tanshinones in roots of S. miltiorrhiza were investigated in detail by monitoring the seedlings within 65 days after germination (DAGs). The ONT transcriptome sequencing was applied to investigate gene expression patterns. The periderm of the S. miltiorrhiza storage taproot initially synthesized tanshinone on about 30 DAGs. Three critical stages of tanshinone synthesis were preliminarily determined: preparation, the initial synthesis, and the continuous rapid synthesis. The difference of taproots in the first two stages was the smallest, and the differentially expressed genes (DEGs) were mainly enriched in terpene synthesis. Most genes involved in tanshinone synthesis were up regulated during the gradual formation of the red taproot. Plant hormone signal transduction and ABC transport pathways were widely involved in S. miltiorrhiza taproot development. Five candidate genes that may participate in or regulate tanshinone synthesis were screened according to the co-expression pattern. Moreover, photosynthetic ferredoxin (FD), cytochrome P450 reductase (CPR), and CCAAT binding transcription factor (CBF) were predicted to interact with the known downstream essential enzyme genes directly. The above results provide a necessary basis for analyzing the initial synthesis and regulation mechanism of Tanshinones

    On the relative importance of buoyancy and lithospheric thickening in mantle upwelling and crustal production beneath global mid-ocean ridge system

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    <p>Source codes of ASPECT used to simulate ridge-like mantle upwelling and melting in manuscript "<strong>On the relative importance of buoyancy and lithospheric thickening in mantle upwelling and crustal production beneath global mid-ocean ridge system</strong>", which has been submit to Journal of Geophysical Research: Solid Earth.</p><p>Input model files *.prm can be found in the directory <i>models</i>.</p&gt

    Identification of the Genome-Wide Expression Patterns of Non-Coding RNAs Associated with Tanshinones Synthesis Pathway in <i>Salvia miltiorrhiza</i>

    No full text
    The red root of Salvia miltiorrhiza Bunge, a famous traditional Chinese medicine (TCM), was caused by tanshinone in epidermis cells. In order to study the biological function of ncRNAs in the tanshinone synthesis, the expression patterns of mRNA and ncRNAs were comprehensively analyzed in red (high tanshinone content) and white root (low tanshinone content) tissues derived from the same plant. A total of 731 differentially expressed genes (DEGs) were mainly enriched in primary metabolic pathways such as galactose and nitrogen, and some secondary metabolic pathways such as phenylpropanoid and terpenoids. A total of 70 miRNAs, 48 lncRNAs, and 26 circRNAs were identified as differentially expressed (DE) ones. The enrichment pathway of the targets of DE-lncRNA were mainly in ribosome, carbon metabolism, plant hormone signal transduction, and glycerophospholipid metabolism. The function of the targets genes of 59 miRNAs combined with DE-circRNAs was mainly involved in plantā€“pathogen interaction, endocytosis, phenylpropanoid biosynthesis, and sesquiterpenoid and triterpenoid biosynthesis pathways. Most genes of the tanshinone synthesis pathway had a higher expression. Some ncRNAs were predicted to regulate several key enzyme genes of the tanshinone synthesis pathway, such as SmDXS2, SmGGPPS1, SmKSL. Furthermore, most target genes were related to the resistance of pathogens. The present study exhibited the tissue-specific expression patterns of ncRNAs, which would provide a basis for further research into the regulation mechanism of ncRNAs in the tanshinone synthesis process

    Effects of hotspotā€induced longā€wavelength mantle melting variations on magmatic segmentation at the Reykjanes Ridge: insights from 3D geodynamic modeling

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    Author Posting. Ā© American Geophysical Union, 20222. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 127(3), (2022): e2021JB023244, https://doi.org/10.1029/2021jb023244.Spatial variations in mantle melting induced by the Iceland hotspot have strong effects on meso-scale mantle upwelling and crustal production along the slow-spreading Reykjanes Ridge. The ridge-hotspot interaction has been recorded by diachronous V-shaped ridges and troughs extending away from Iceland, as well as by changes in ridge segmentation since 37 Ma. The origins of V-shaped structures are widely debated, while the causes of the gradual erasion of ridge segments bounded by transform faults are rarely investigated. Through 3D time-dependent geodynamic modeling, this study investigates how the hotspot-induced regional mantle melting variations affect ridge segmentation. Periodic temperature perturbations were initially imposed beneath the melting zone to trigger buoyant upwelling cells, which corresponded to the offset ridge segments at the Reykjanes Ridge. Iceland hotspot-induced long-wavelength mantle melting variations were generated by applying a regional linear temperature gradient at the bottom of the model domain. Modeling reveals a two-stage evolution of the buoyant upwelling cells that characterizes the segmentation transition at the Reykjanes Ridge. In Stage 1, the regional mantle melting variations trigger along-axis pressure-driven mantle flow, which alters the segment-scale mantle upwelling and promotes the propagation of segment boundaries away from the region with relatively higher mantle temperature. In Stage 2, buoyant upwelling cells are destroyed progressively as along-axis mantle flow dominants, leaving V-shaped diachronous boundaries between the segmented and unsegmented crust. These results advance our understanding of the effects of long-wavelength mantle melting variations induced by regional mantle heterogeneities on ridge segment evolution at slow-spreading ridges.This work was supported by Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2019ZD0205); the National Science Foundation of China (41890813, 41976066, 91858207, 41976064, and 91628301); the Chinese Academy of Sciences (Y4SL021001, QYZDY-SSW-DQC005, 133244KYSB20180029, 131551KYSB20200021 and ISEE2021PY03); the Guangdong Basic and Applied Basic Research Foundation (2021A1515012227); the National Key Research and Development Program of China (2018YFC0309800 and 2018YFC0310105), and the Hainan Provincial Natural Science Foundation of China (421QN381). We thank the Computational Infrastructure for Geodynamics (geodynamics.org) which is funded by the National Science Foundation (EAR-0949446 and EAR-1550901) for supporting the development of ASPECT (https://geodynamics.org/cig/software/aspect/). The numerical simulation is supported by the High-Performance Computing Division in the South China Sea Institute of Oceanology. Figures were drawn using the GMT software of Wessel and Smith (1998)
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