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Rosa1, a Transposable Element-Like Insertion, Produces Red Petal Coloration in Rose Through Altering RcMYB114 Transcription
No full textRose (Rosa sp.) flowers have a rich diversity of colors resulting from the differential accumulation of anthocyanins, flavonols, and carotenoids. However, the genetic and molecular determinants of the red-petal trait in roses remains poorly understood. Here we report that a transposable element-like insertion (Rosa1) into RcMYB114, a R2R3-MYB transcription factor's promoter region causes its transcription, resulting in red petals. In red-petal varieties, RcMYB114 is expressed specifically in flower organs, but is absent from non-red varieties. Sequencing, yeast two-hybrid, transient transformation, and promoter activity assays of RcMYB114 independently confirmed the role of Rosa1 in altering RcMYB114's transcription and downstream effects on flower color. Genetic and molecular evidence confirmed that the Rosa1 transposable element-like insertion, which is a previously unknown DNA transposable element, is different from those in other plants and is a reliable molecular marker to screen red-petal roses
We Must Stop Fossil Fuel Emissions to Protect Permafrost Ecosystems
No full textClimate change is an existential threat to the vast global permafrost domain. The diverse human cultures, ecological communities, and biogeochemical cycles of this tenth of the planet depend on the persistence of frozen conditions. The complexity, immensity, and remoteness of permafrost ecosystems make it difficult to grasp how quickly things are changing and what can be done about it. Here, we summarize terrestrial and marine changes in the permafrost domain with an eye toward global policy. While many questions remain, we know that continued fossil fuel burning is incompatible with the continued existence of the permafrost domain as we know it. If we fail to protect permafrost ecosystems, the consequences for human rights, biosphere integrity, and global climate will be severe. The policy implications are clear: the faster we reduce human emissions and draw down atmospheric CO2, the more of the permafrost domain we can save. Emissions reduction targets must be strengthened and accompanied by support for local peoples to protect intact ecological communities and natural carbon sinks within the permafrost domain. Some proposed geoengineering interventions such as solar shading, surface albedo modification, and vegetation manipulations are unproven and may exacerbate environmental injustice without providing lasting protection. Conversely, astounding advances in renewable energy have reopened viable pathways to halve human greenhouse gas emissions by 2030 and effectively stop them well before 2050. We call on leaders, corporations, researchers, and citizens everywhere to acknowledge the global importance of the permafrost domain and work towards climate restoration and empowerment of Indigenous and immigrant communities in these regions
Analysis of edible characteristics, antioxidant capacities, and phenolic pigment monomers in Lilium bulbs native to China
No full textLilium is cherished for its health-promoting properties in China. The bulbs of Lilium are rich in phenolic compounds, which are associated with antioxidant capacity. However, no systematic evaluation on phenolic compositions and antioxidant capacities for the edible Lilium native to China has been conducted. Herein, bulbs of 56 wild populations and three cultivars were collected. Their edible characteristics, antioxidant capacities, and pigments have been investigated and analyzed. The results showed that phenolic compounds contributed to the major colors (red, yellow and white) in Lilium bulbs. The seven phenolic pigment monomers responsible for the color of bulbs-cyanidin-3-O-rutinoside, isoquercitrin, regaloside B, regaloside C, regaloside H, regaloside A and regaloside D-were identified by the combination of HPLC-MS and NMR analysis. The population Lilium regale E. H. Wilson (Maoxian County, Sichuan Province) had the highest antioxidant capacity. According to the quantification results, Lilium bulbs with darker and redder colors possessed larger biomass, better nutrient compositions, significantly higher bioactive constituents, and higher antioxidant capacities than the three currently consumed cultivars of edible lily bulbs. Overall, these findings suggest that the mountainous area of southwest China could be the fourth source of edible lilies with the bulb-colored Lilium species
Tree-ring evidence of ecological stress memory
No full textPlants experiencing stress could develop the ability to reshape their response toward present stress based on past stress experience, called 'ecological stress memory' (ESM), which is important for plant acclimation to repeated stresses. Although ESM has been largely reported, it remains unclear whether ESM could improve tree resistance to recurrent stress in subsequent decades. Here, we explore it from a tree-ring network of 1491 trees from 50 long-living juniper forests on the Tibetan Plateau. Through comparing performances of tree radial growth in past sequential growth stresses, we found that trees could obtain ESM under antecedent stresses and elevate resistance to subsequent stress after several years or even decades. Such positive effects of ESM are associated with post-stress recovery. Trees with slow recovery trajectories after antecedent stress show significantly improved resistance to subsequent stress, while trees with extremely fast post-stress recovery showed decreased resistance to subsequent stress. These results imply that temporary depressive tree radial growth after antecedent stress might be a trigger of long storage of ESM. Incorporating positive effects of ESM and relationship between ESM activation and post-stress recovery into future Earth system models could advance our capacity to predict forest dynamics and forest ecosystem stabilization under future stress conditions
Tree diversity depending on environmental gradients promotes biomass stability via species asynchrony in China?s forest ecosystems
No full textThere is mounting evidence that biodiversity promotes ecological stability in changing environments. However, understanding diversity-stability relationships and their underlying mechanisms across large-scale tree diversity and natural environmental gradients are still controversial and largely lacking. We used thirty-nine 0.12 ha longterm permanent forest plots spanning China's various forest types to test the effects of multiple abiotic (climate, soil, age and topography) and biotic factors (taxonomic and structural diversity, functional diversity and community-mean traits, and species asynchrony) on biomass stability and its components (mean biomass and biomass variability) over time. We used multiple analytical methods to identify the best explanatory variables and complicated causal relationships for community biomass stability. Our results showed that species richness increased biomass stability by promoting species asynchrony. Structural and functional diversity had a weaker effect on biomass stability. Forest age and structural diversity increased mean biomass and biomass variability significantly and simultaneously. Communities dominated by tree species with high wood density had high biomass stability. Soil nitrogen enhanced biomass stability directly and indirectly through its effects on mean biomass. Soil nitrogen to phosphorus ratio increased biomass stability via increasing species asynchrony. Precipitation indirectly increased biomass stability by affecting tree diversity. Moreover, the direct and indirect effects of soil nutrients on biomass stability were greater than that of climate variables. Our results suggest that species asynchrony is the main mechanism proposed to explain the stabilizing effect of diversity on community biomass, supporting two mechanisms, namely, the biodiversity insurance hypothesis and complementary dynamics. Soil and climate factors also play an important role in shaping diversity-stability relationships. Our results provide a new insight into how tree diversity affects ecosystem stability across diverse community types and large-scale environmental gradients
Plastid phylogenomic analyses of the Selaginella sanguinolenta group (Selaginellaceae) reveal conflict signatures resulting from sequence types, outlier genes, and pervasive RNA editing
No full textDifferent from the generally conserved plastomes (plastid genomes) of most land plants, the Selaginellaceae plastomes exhibit dynamic structure, high GC content and high substitution rates. Previous plastome analyses identified strong conflict on several clades in Selaginella, however the factors causing the conflictions and the impact on the phylogenetic inference have not been sufficiently investigated. Here, we dissect the distribution of phylogenetic signals and conflicts in Selaginella sanguinolenta group, the plastome of which is DR (direct repeats) structure and with genome-wide RNA editing. We analyzed the data sets including 22 plastomes representing all species of the S. sanguinolenta group, covering the entire geographical distribution from the Himalayas to Siberia and the Russian Far East regions. We recovered four different topologies by applying multispecies coalescent (ASTRAL) and concatenation methods (IQ-TREE and RAxML) on four data sets of PC (protein-coding genes), NC (non-coding sequences), PCN (the concatenated PC and NC), and RC (predicted RNA editing sites C were corrected by T ), respectively. Six monophyletic clades, S. nummularifolia clade, S. rossii clade, S. sajanensis clade, S. sanguinolenta I clade, S. sanguinolenta II clade, and S. sanguinolenta III clade, were consistently resolved and supported by the characteristics of GC content, RNA editing frequency, and gene content. However, the relationships among these clades varied across the four topologies. To explore the underlying causes of the uncertainty, we compared the phylogenetic signals of the four topologies. We identified that the sequence types (coding versus non-coding), outlier genes (genes with extremely high |delta GLS| values), and C-to-U RNA editing frequency in the protein-coding genes were responsible for the unstable phylogenomic relationship. We further revealed a significant positive correlation between the |delta GLS| values and the variation coefficient of the RNA editing number. Our results demonstrated that the coalescent method performed better than the concatenation method in overcoming the problems caused by outlier genes and extreme RNA editing events. Our study particularly focused on the importance of exploring the plastid phylogenomic conflicts and suggested conducting concatenated analyses cautiously when adopting organelle genome data
Patterns of daily stem growth in different tree species in a warm-temperate forest in northern China
No full textRadial growth in trees responds to environmental changes in various ways ranging from immediate to hysteretic responses. However, species-specific tree radial growth patterns and their responses to short-term weather changes are not fully understood. Here, the daily stem radial changes (SRCs) in four common tree species, linden (Tilia mongolica), birch (Betula dahurica), oak (Quercus wutaishanica) and larch (Larix principis-rupprechtii), were monitored with high-resolution point dendrometers during the main growing seasons in 2017-2019 on Dongling Mountain, northern China. The SRC was differentiated into tree water deficit-induced stem shrinkage (TWD) and growth-induced irreversible stem expansion (GRO) to evaluate species-specific responses to weather variables and short-term drought events. We found that the TWD and GRO of the four species were significantly different. The TWD was influenced primarily by the vapor pressure deficit (VPD), whereas the GRO was influenced primarily by precipitation (P). In linden and birch, a larger proportion of the GRO occurred at higher air temperature (T-mean) and VPD values; in contrast, the range of these changes was lower in oak and larch. With the increased durations of drought periods, oak and larch experienced large and rapid increases in TWD, whereas birch and linden showed small and slow increases. These results indicate that oak and larch would be sensitive to warmer and drier weather conditions predicted for the future, while linden and birch would have a conservative growth strategy. Our results provide further insights into the physiology of these four tree species and allow us to better predict the growth response of forest dynamics under climate change
PHYLOGENETIC EXPLORATION OF TRADITIONAL CHINESE MEDICINAL PLANTS: A CASE STUDY ON LAMIACEAE
No full textLamiaceae (Labiatae) are one of the most important medicinal plant families having a wide variety of plants with traditional medicinal uses. The medicinal species of Lamiaceae are mainly used for musculoskeletal, skin, circulatory and digestive disorders in traditional Chinese medicines (TCMs). The purpose of this study was to provide a phylogenetic exploration of traditionally used medicinal taxa of Lamiaceae as a roadmap to predict potential medicinal plants from this family for future bioprospecting. We collected data of Lamiaceae TCM plants from local pharmacopeias with traditional medicinal uses and phytochemical information. The data were examined through phylogenetic approaches i.e. nearest taxon index (NTI) and net related index (NRI) to find clustering and overdispersion of TCM plants of Lamiaceae. In addition, we used hot node analysis to identify overrepresentation among lineages against different disorders that possess high priority for further phytochemical and pharmacological investigation. The phylogenetic patterns were examined for the traditional uses of 345 species belonging to 77 Lamiaceae genera in nine medicinal categories. Overall, most of the medicinal uses showed clustered structure on the phylogeny of TCM plants of Lamiaceae (NRI and NTI 1). Of all the nine medicinal usage categories, the NRI matrix identified only two significant clusterings with p<0.05 for urinary and reproductive disorders. In total of 488 hot nodes that are significantly overabundant in species are used to treat different disorders. The highest number of hot nodes recovered was 191 for reproductive disorder, of these 138 species were reported to be potential novel species. The majority of new potential species were reported from Ajuga, Elsholtzia and Salvia. These results strongly indicate the independent discovery of plant usages in the light of phylogenetic exploration. We concluded that phylogenetic approaches could focus on screening efforts of taxonomic groups containing traditionally used species with abundant therapeutic compounds for the discovery of alternative/complementary medicines. The phylogeny-based study, after further refinement, will expand the horizon of medicinal plant exploration of plant-based bioactive compounds
Differences in the functional properties and starch structures of early/late season rice between the early and late seasons
No full textIn the double rice cropping system, early/late season rice cultivars can be grown in both early and late seasons. However, the functional properties and starch structures of early/late-season rice between the early and late seasons are still unclear. Here, we conducted a field experiment with two typical early/late season rice cultivars. Compared to early rice, late rice had higher hardness and stickiness and lower peak viscosity, breakdown, and pasting temperature. The higher hardness, lower peak viscosity and breakdown of late rice were dominated by its higher amylose content (i.e., the proportion of amylose chains, DP 100-10000). The lower crystallinity and ratio of 1045/1022 cm-1 of late rice was due to its long and very long amylopectin branch chains (DP 25-70), resulting in a lower pasting temperature. We considered that the higher stickiness of late rice was due to a higher proportion of short and medium amylopectin branch chains (DP 6-24). Furthermore, the setback (short-term retrogradation) showed a significant difference between cultivars, which might be related to the difference in long amylopectin branch chains (DP 37-70) and their intermolecular interactions with amylose molecules. These findings are expected to provide important information for improving rice palatability and developing the rice industry of early/late season rice in the double rice cropping system
Sustained increases in soil respiration accompany increased carbon input under long-term warming across global grasslands
No full textRespiratory effluxes of carbon (C) from the soil to the atmosphere are expected to rise with temperature, potentially intensifying future climate warming. However, whether and how this increase would be sustained under long-term warming is not well understood. Here, we combined a manipulation experiment in an alpine meadow with a global meta-analysis to explore the mechanisms underlying the long-term responses of soil respiration to climate warming. The results from the experiment in the alpine meadow showed that the warming-induced increase in net primary productivity (NPP, 23.6 %) explained 52 % of the increase in soil respiration across 6 years. In contrast, the warming-induced changes in soil moisture, soil temperature, microbial biomass C or nitrogen were not significantly correlated with soil respiration responses. Consistently, in the global meta- analysis, both soil respiration and NPP continually increased over the years by an average of 9.5 % and 15.9 %, respectively. The increases in soil respiration were also primarily correlated with the continued increases in NPP over this period. Notably, the sustained increase in soil respiration was mainly contributed by the response of autotrophic respiration, which was closely correlated with the sustained increase in belowground NPP under warming. The results from both our field experiment and meta-analysis suggest that the increased soil respiration under climate warming was at least partly from the stimulation of C input in grasslands. The simultaneous in-creases in soil respiration and NPP may counteract the expected positive terrestrial C-climate feedback and should be considered in land models to more accurately predict future climate change