of Botany,Chinese Academy Of Sciences
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ERF49 mediates brassinosteroid regulation of heat stress tolerance in Arabidopsis thaliana
No full textBackground Heat stress is a major abiotic stress affecting the growth and development of plants, including crop species. Plants have evolved various adaptive strategies to help them survive heat stress, including maintaining membrane stability, encoding heat shock proteins (HSPs) and ROS-scavenging enzymes, and inducing molecular chaperone signaling. Brassinosteroids (BRs) are phytohormones that regulate various aspects of plant development, which have been implicated also in plant responses to heat stress, and resistance to heat in Arabidopsis thaliana is enhanced by adding exogenous BR. Brassinazole resistant 1 (BZR1), a transcription factor and positive regulator of BR signal, controls plant growth and development by directly regulating downstream target genes. However, the molecular mechanism at the basis of BR-mediated heat stress response is poorly understood. Here, we report the identification of a new factor critical for BR-regulated heat stress tolerance. Results We identified ERF49 in a genetic screen for proteins required for BR-regulated gene expression. We found that ERF49 is the direct target gene of BZR1 and that overexpressing ERF49 enhanced sensitivity of transgenic plants to heat stress. The transcription levels of heat shock factor HSFA2, heat stress-inducible gene DREB2A, and three heat shock protein (HSP) were significantly reduced under heat stress in ERF49-overexpressed transgenic plants. Transcriptional activity analysis in protoplast revealed that BZR1 inhibits ERF49 expression by binding to the promoter of ERF49. Our genetic analysis showed that dominant gain-of-function brassinazole resistant 1-1D mutant (bzr1-1D) exhibited lower sensitivity to heat stress compared with wild-type. Expressing ERF49-SRDX (a dominant repressor reporter of ERF49) in bzr1-1D significantly decreased the sensitivity of ERF49-SRDX/bzr1-1D transgenic plants to heat stress compared to bzr1-1D. Conclusions Our data provide clear evidence that BR increases thermotolerance of plants by repressing the expression of ERF49 through BZR1, and this process is dependent on the expression of downstream heat stress-inducible genes. Taken together, our work reveals a novel molecular mechanism mediating plant response to high temperature stress
Human-Climate Coupled Changes in Vegetation Community Complexity of China Since 1980s
No full textVegetation community complexity is a critical factor influencing terrestrial ecosystem stability. China, the country leading the world in vegetation greening resulting from human activities, has experienced dramatic changes in vegetation community composition during the past 30 years. However, how China's vegetation community complexity varies spatially and temporally remains unclear. Here, we examined the spatial pattern of China's vegetation community complexity and its temporal changes from the 1980s to 2015 using two vegetation maps of China as well as more than half a million field samples. Spatially, China's vegetation community complexity distribution is primarily dominated by elevation, although temperature and precipitation can be locally more influential than elevation when they become the factors limiting plant growth. Temporally, China's vegetation community complexity shows a significant decreasing trend during the past 30 years, despite the observed vegetation greening trend. Prevailing climate warming across China exhibits a significant negative correlation with the decrease in vegetation community complexity, but this correlation varies with biogeographical regions. The intensity of human activities have an overall negative influence on vegetation community complexity, but vegetation conservation and restoration efforts can have a positive effect on maintaining vegetation composition complexity, informing the critical role of vegetation management policies in achieving the sustainable development goal
Climate Sensitivities of Carbon Turnover Times in Soil and Vegetation: Understanding Their Effects on Forest Carbon Sequestration
No full textThe high uncertainty associated with the response of terrestrial carbon (C) cycle to climate is dominated by ecosystem C turnover time (tau(eco)). Although the relationship between tau(eco) and climate has been extensively studied, significant knowledge gaps remain regarding the differential climate sensitivities of turnover time in major biomass (tau(veg)) and soil (tau(soil)) pools, and their effects on vegetation and soil C sequestration under climate change are poorly understood. Here, we collected multiple time series observations on soil and vegetation C from permanent plots in 10 Chinese forests and used model-data fusion to retrieve key C cycle process parameters that regulate tau(soil) and tau(veg). Our analysis showed that tau(veg) and tau(soil) both decreased with increasing temperature and precipitation, and tau(soil) was more than twice as sensitive (1.27 years/degrees C, 1.70 years/100 mm) than tau(veg) (0.53 years/degrees C, 0.40 years/100 mm). The higher climate sensitivity of tau(soil) caused a more rapid decrease in tau(soil) than in tau(veg) with increasing temperature and precipitation, thereby significantly reducing the difference between tau(soil) and tau(veg) (tau(diff)) under warm and humid conditions. tau(diff), an indicator of the balance between the soil C input and exit rate, was strongly responsible for the variation (more than 50%) in soil C sequestration. Therefore, a smaller tau(diff) under warm and humid conditions suggests a relatively lower contribution from soil C sequestration. This information has strong implications for understanding forest C-climate feedback, predicting forest C sink distributions in soil and vegetation under climate change, and implementing C mitigation policies in forest plantations or soil conservation
Forbs dominate plant nutrient resorption of plant community along a 34-year grazing exclusion gradient in a semiarid grassland
No full textGrazing exclusion has been commonly used to restore degraded grasslands and has shown positive effects on plant community structure, productivity, and soil properties. Nutrient resorption affects key ecosystem processes such as nutrient uptake and carbon cycling, and plays a key role in plants' nutrient conservation in nutrient-poor environments. However, how plant nutrient resorption varying with grazing exclusion duration remains unclear. In this study, leaf nitrogen (N) and phosphorus (P) resorption efficiencies were examined at plant functional group and community levels in grasslands along a 34-year grazing exclusion gradient. Along the grazing exclusion gradient, N resorption efficiency (NRE) of plant community remained unchanged, while P resorption efficiency (PRE) increased, accompanied with increased community biomass, the proportion of grasses and soil fertility. Nutrient concentrations and resorption efficiencies, as well as their responses to grazing exclusion, varied among plant functional groups. Both NRE and PRE were higher in grasses than in sedges or forbs, while forbs had higher N and P concentrations in both green and senesced leaves. NRE and PRE of grasses and sedges changed little along the grazing exclusion gradient except the decreased NRE of grasses after 34 years of grazing exclusion, while both NRE and PRE of forbs increased with the duration of grazing exclusion. Variation in community nutrient resorption efficiencies was largely driven by forbs, and nutrient resorption efficiencies were negatively correlated with senesced leaf nutrient concentrations. Nutrient concentrations and resorption efficiencies of different plant functional groups and plant communities varied in their relationships with soil properties. Overall, our study highlights the importance of forbs in plant nutrient use pattern of grassland communities along the grazing exclusion gradient, and offer insights for grassland management to boost ecosystem nutrient cycling
Chromosome-level assembly and analysis of the Thymus genome provide insights into glandular secretory trichome formation and monoterpenoid biosynthesis in thyme
No full textThyme hasmedicinal and aromatic value because of its potent antimicrobial and antioxidant properties. However, the absence of a fully sequenced thyme genome limits functional genomic studies of Chinese native thymes. Thymus quinquecostatus Celak., which contains large amounts of bioactive monoterpenes such as thymol and carvacrol, is an important wild medicinal and aromatic plant in China. Monoterpenoids are abundant in glandular secretory trichomes. Here, high-fidelity and chromatin conformation capture technologies were used to assemble and annotate the T. quinquecostatus genome at the chromosome level. The 13 chromosomes of T. quinquecostatus had a total length of 528.66 Mb, a contig N50 of 8.06 Mb, and a BUSCO score of 97.34%. We found that T. quinquecostatus had experienced two whole-genome duplications, with the most recent event occurring similar to 4.34 million years ago. Deep analyses of the genome, in conjunction with comparative genomic, phylogenetic, transcriptomic, and metabonomic studies, uncovered many regulatory factors and genes related to monoterpenoids and glandular secretory trichome development. Genes encoding terpene synthase (TPS), cytochrome P450 monooxygenases (CYPs), short-chain dehydrogenase/reductase (SDR), R2R3-MYB, and homeodomain-leucine zipper (HD-ZIP) IV were among those present in the T. quinquecostatus genome. Notably, Tq02G002290.1 (TqTPS1) was shown to encode the terpene synthase responsible for catalyzing production of the main monoterpene product gamma-terpinene from geranyl diphosphate (GPP). Our study provides significant insight into themechanisms of glandular secretory trichome formation and monoterpenoid biosynthesis in thyme. This work will facilitate the development of molecular breeding tools to enhance the production of bioactive secondary metabolites in Lamiaceae
Proximal and remote sensing in plant phenomics: 20 years of progress, challenges, and perspectives
No full textPlant phenomics (PP) has been recognized as a bottleneck in studying the interactions of genomics and environment on plants, limiting the progress of smart breeding and precise cultivation. High-throughput plant phenotyping is challenging owing to the spatio-temporal dynamics of traits. Proximal and remote sensing (PRS) techniques are increasingly used for plant phenotyping because of their advantages in multi-dimensional data acquisition and analysis. Substantial progress of PRS applications in PP has been observed over the last two decades and is analyzed here from an interdisciplinary perspective based on 2972 publications. This progress covers most aspects of PRS application in PP, including patterns of global spatial distribution and temporal dynamics, specific PRS technologies, phenotypic research fields, working environments, species, and traits. Subsequently, we demonstrate how to link PRS to multi-omics studies, including how to achieve multi-dimensional PRS data acquisition and processing, how to systematically integrate all kinds of phenotypic information and derive phenotypic knowledge with biological significance, and how to link PP to multi-omics association analysis. Finally, we identify three future perspectives for PRS-based PP: (1) strengthening the spatial and temporal consistency of PRS data, (2) exploring novel phenotypic traits, and (3) facilitating multi- omics communication
The uplift of the Hengduan Mountains contributed to the speciation of three Rhododendron species
No full textPlant speciation in mountain systems is crucial for shaping plant biodiversity, particularly for those endemic species with small populations. The mountain-geobiodiversity hypothesis (MGH) is among the possible mechanisms underlying mountain biodiversity. To test the MGH, we selected three Rhododendron species occupying the Hengduan Mountains (HDM) as focal species and then genotyped 12 populations using Restriction-site Associated DNA sequencing (RAD-seq) to reveal their speciation and divergence history. We found that there was high interspecific differentia-tion, low gene flow, and a high genetic drift among three Rhododendron species, suggesting that founder effects might play a key role in their differentiation. Historical gene flow occurred from R. brachypodum to R. calophytum var. pauciflorum. The effective population size of three Rhodo-dendron species declined about 1 Kya ago. Rhododendron brachypodum experienced a bottleneck event during the Last Glacial Maximum (15-20 Kya). Three Rhododendron species diverged be-tween 15.5 Mya and 3.13 Mya, which might be associated with the uplift of the HDM. These findings suggest that the speciation of three Rhododendron may be partly attributable to geological processes and climate fluctuations, strongly supporting the MGH. Additionally, our results provide new insights into the speciation patterns of endemic species and the protection of narrow-ranged species in mountain systems
Disentangling the effects of the surrounding environment on street-side greenery: Evidence from Hangzhou
No full textHuman-scale greenery has been heavily featured in the development of planning-related theories and research. Daily exposure to street greenery is proportionately greater than exposure to parks. Several case studies have estimated the green view index (GVI), which quantifies daily exposure to street-side greenery, at the city-scale. However, the street-side greenery distribution is uneven. The relationship between the GVI and the surrounding environment has rarely been discussed. Here, we investigate the differentiation of street greenery from the physical features of a street and examine how the surrounding environment affects the physical appearance of eye-level greenery. In this work, we analyzed the GVI using the internet data crawling approach and obtained 12,232 panoramic street view images from Baidu Map for the urban zones of Hangzhou, China. A range of 17 surrounding environmental characteristics are integrated with multisource geographic data to analyze their relationship with the GVI at the microscale. Spatial econometric models are explored to provide insights into the underlying mechanisms associated with the GVI. The results showed that the surrounding environment exhibited a strong role in the physical appearance of eye-level greenness. There are two pathways through which surrounding environmental characteristics (the nature of land use and the enclosure of the street) affect the distribution of GVI. Four factors proved to be important: scenic protection policies and ecological renewal projects, vertical and horizontal green characteristics of different land uses, and facade designs dominated by enclosed exterior walls or railing walls. Interesting approaches are presented to rationally implement activities related to these factors. The urban green design process should be facilitated in terms of the trade-off between greenery and optimum land use. These findings can be useful in drafting appropriate policies and increasing eye-level greenery in cities
Unraveling the Glucosylation of Astringency Compounds of Horse Chestnut via Integrative Sensory Evaluation, Flavonoid Metabolism, Differential Transcriptome, and Phylogenetic Analysis
No full textThe seeds of Chinese horse chestnut are used as a source of starch and escin, whereas the potential use of whole plant has been ignored. The astringency and bitterness of tea produced from the leaves and flowers were found to be significantly better than those of green tea, suggesting that the enriched flavonoids maybe sensory determinates. During 47 flavonoids identified in leaves and flowers, seven flavonol glycosides in the top 10 including astragalin and isoquercitrin were significantly higher content in flowers than in leaves. The crude proteins of flowers could catalyze flavonol glucosides' formation, in which three glycosyltransferases contributed to the flavonol glucosylation were screened out by multi-dimensional integration of transcriptome, evolutionary analyses, recombinant enzymatic analysis and molecular docking. The deep exploration for flavonol profile and glycosylation provides theoretical and experimental basis for utilization of flowers and leaves of Aesculus chinensis as additives and dietary supplements
Unveiling ochratoxin a controlling and biodetoxification molecular mechanisms: Opportunities to secure foodstuffs from OTA contamination
No full textAnarchic growth of ochratoxin A (OTA) producing fungi during crop production, prolonged storage, and processing results in OTA contamination in foodstuffs. OTA in food exacerbates the risk of health and economic problems for consumers and farmers worldwide. Although the toxic effects of OTA on human health have not been well established, comprehensive preventive and remedial measures will be essential to eliminate OTA from foodstuffs. Strict regulations, controlling OTA at pre-or post-harvest stage, and decontamination of OTA have been adopted to prevent human and animal OTA exposure. Biological control of OTA and bio-decontamination are the most promising strategies due to their safety, specificity and nutritional value. This review addresses the current understanding of OTA biodegradation mechanisms and recent developments in OTA control and bio-decontamination strategies. Additionally, this review analyses the strength and weaknesses of different OTA control methods and the contemporary approaches to enhance the efficiency of biocontrol agents. Overall, this review will support the implementation of new strategies to effectively control OTA in food sectors. Further studies on efficacy-related issues, production issues and cost-effectiveness of OTA biocontrol are to be carried out to improve the knowledge, develop improved delivery technologies and safeguard the durability of OTA biocontrol approaches