of Botany,Chinese Academy Of Sciences
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New evidence of the emergence of the East Asian monsoon in the early Palaeogene
No full textPrevious palaeoenvironmental reconstructions have implied that East Asia was dominated by a zonal climate pattern during the Eocene, with an almost latitudinal arid/semiarid band at similar to 30 degrees N. However, this long-standing model has recently been challenged by growing body of multidisciplinary evidence. Some studies indicated that central China was characterized by climatic fluctuations between humid and drier conditions during the Early Eocene, akin to the present East Asian monsoon (EAM) regime. Using palynological assemblages in the Tantou Basin, central China, we quantitatively reconstructed climate changes from the Late Palaeocene to Early Eocene to better understand climate change in central China. Palynological assemblages revealed that the coniferous and broad-leaved mixed forest in this area received no less than 800 mm of annual precipitation and experienced a climate change from warm and wet to relatively cool and dry. According to palaeoclimate curves, a sudden climate change occurred in the Early Eocene, with the mean annual temperature and precipitation decreasing by 5.1 degrees C and 214.8 mm, respectively, and the climate became very similar to the present climate, which is controlled by the monsoon. Therefore, this significant climate change during the Early Eocene may signal the emergence of the EAM in East Asia
Chromosome-level and haplotype-resolved genome provides insight into the tetraploid hybrid origin of patchouli
No full textThe ploidy level of patchouli, an aromatic plant in the Lamiaceae family, remain unclear. Here, the authors assemble a chromosome-level and haplotype-resolved genome for patchouli and reveal that it is tetraploid hybrid as well as compensated aneuploidy. Patchouli (Pogostemon cablin (Blanco) Benth.), a member of the Lamiaceae family, is an important aromatic plant that has been widely used in medicine and perfumery. Here, we report a 1.94 Gb chromosome-scale assembly of the patchouli genome (contig N50 = 7.97 Mb). The gene annotation reveals that tandem duplication of sesquiterpene biosynthetic genes may be a major contributor to the biosynthesis of patchouli bioactivity components. We further phase the genome into two distinct subgenomes (A and B), and identify a chromosome substitution event that have occurred between them. Further investigations show that a burst of universal LTR-RTs in the A subgenome lead to the divergence between two subgenomes. However, no significant subgenome dominance is detected. Finally, we track the evolutionary scenario of patchouli including whole genome tetraploidization, subgenome divergency, hybridization, and chromosome substitution, which are the key forces to determine the complexity of patchouli genome. Our work sheds light on the evolutionary history of patchouli and offers unprecedented genomic resources for fundamental patchouli research and elite germplasm development
Multidimensional exploration of essential oils generated via eight oregano cultivars: Compositions, chemodiversities, and antibacterial capacities
No full textNumerous species of Origanum (Lamiaceae) have been widely used as spices to extend the shelf life of foods. Essential oils extracted from this genus have attracted much attention owing to their potential applications as bactericides. Here, we evaluated the chemical compositions of eight oregano essential oils (OEOs) using gas chromatography-mass spectrometry and assessed their antibacterial activities. The chemical compositions of OEOs were affected by the cultivar factor, and seven common compounds, including carvacrol, were identified among eight OEOs. Partial least squares discriminant analysis enabled the distinction of three groups among these OEOs, as characterized by the proportions of carvacrol, thymol, and sesquiterpenes. OEOs effectively inhibited Escherichia coli and Staphylococcus aureus with varying antibacterial activities. Spearman correlation network highlighted core antibacterial contributors in the chemical profiles of OEOs. Our results revealed that the bacteriostatic effects of OEOs could be explained by core compounds and their synergistic effects
Making sense of multivariate community responses in global change experiments
No full textEcological communities are being impacted by global change worldwide. Experiments are a powerful tool to understand how global change will impact communities by comparing control and treatment replicates. Communities consist of multiple species, and their associated abundances make multivariate methods an effective approach to study community compositional differences between control and treated replicates. Dissimilarity metrics are a commonly employed multivariate measure of compositional differences; however, while highly informative, dissimilarity metrics do not elucidate the specific ways in which communities differ. Integrating two multivariate methods, dissimilarity metrics and rank abundance curves (RACs), have the potential to detect complex differences based on dissimilarity metrics and detail the how these differences came about through differences in richness, evenness, species ranks, or species identity. Here we use a database of 106 global change experiments located in herbaceous ecosystems and explore how patterns of ordinations based on dissimilarity metrics relate to RAC-based differences. We find that combining dissimilarity metrics alongside RAC-based measures clarifies how global change treatments are altering communities. We find that when there is no difference in community composition (no distance between centroids of control and treated replicates), there are rarely differences in species ranks or species identities and more often differences in richness or evenness alone. In contrast, when there are differences between centroids of control and treated replicates, this is most often associated with differences in ranks either alone or co-occurring with differences in richness, evenness, or species identities. We suggest that integrating these two multivariate measures of community composition results in a deeper understanding of how global change impacts communities
Solanum lycopersicum, a Model Plant for the Studies in Developmental Biology, Stress Biology and Food Science
No full textFruits, vegetables and other plant-derived foods contribute important ingredients for human diets, and are thus favored by consumers worldwide. Among these horticultural crops, tomato belongs to the Solanaceae family, ranks only secondary to potato (S. tuberosum L.) in yields and is widely cultivated for fresh fruit and processed foods owing to its abundant nutritional constituents (including vitamins, dietary fibers, antioxidants and pigments). Aside from its important economic and nutritional values, tomato is also well received as a model species for the studies on many fundamental biological events, including regulations on flowering, shoot apical meristem maintenance, fruit ripening, as well as responses to abiotic and biotic stresses (such as light, salinity, temperature and various pathogens). Moreover, tomato also provides abundant health-promoting secondary metabolites (flavonoids, phenolics, alkaloids, etc.), making it an excellent source and experimental system for investigating nutrient biosynthesis and availability in food science. Here, we summarize some latest results on these aspects, which may provide some references for further investigations on developmental biology, stress signaling and food science
Transcriptomic comparison sheds new light on regulatory networks for dimorphic flower development in response to photoperiod in Viola prionantha
No full textBackground Chasmogamous (CH)-cleistogamous (CL) dimorphic flowers are developed in Viola prionantha. However, the environmental and genetic factors necessary for the CH-CL transition are unknown. Results In the present work, short-day (SD) conditions induced CH flowers, whereas long days (LDs) triggered CL flowers in V. prionantha. Compared to fully developed CH flowers, CL flowers had less mature stamens, no nectar glands, and immature petals. Comparative transcriptomics revealed differentially expressed genes (DEGs) during CL and CH development. Core genes in the photoperiod pathway, such as V. prionantha orthologs of GIGANTEA (GI), CONSTANS (CO), and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1), which promote floral induction, were highly expressed in CL flowers, whereas UNUSUAL FLORAL ORGANS (UFO) and B-class MADS-box genes for floral organ identity and development showed an opposite alteration. Moreover, genes in the glycolytic process, sucrose metabolic process, and fatty acid biosynthetic process were all highly expressed in CH flowers. Interestingly, V. prionantha orthologs of the B-class MADS-box genes APETALA3 (AP3) and PISTILLATA (PI) might relate to these sugar-fatty acid processes and were co-expressed with GAIP-B-like and YABBY5 (YAB5), which regulate the development of the petal, stamen, and nectary. Compared to CH flowers, DEGs and hub genes in the most significantly correlated modules of the gene co-expression network, which are involved in abiotic and biotic responses, were upregulated in CL flowers. Conclusions We proposed an integrative model for transcription regulation of genes in the photoperiod pathway, floral organ development, stress response, and sugar-fatty acid processes to determine CH-CL flower development in V. prionantha. Particularly, under LDs, activated GI may induce genes involved in the stress-response pathways, and then downregulated AP3 and PI or UFO to inhibit the sugar-fatty acid metabolic processes, together forming CL flowers. In contrast, CH flowers were produced under SDs. This work provides novel insights into the developmental evolution of dimorphic flowers in Viola
Identification and Investigation of the Genetic Variations and Candidate Genes Responsible for Seed Weight via GWAS in Paper Mulberry
No full textSeeds directly determine the survival and population size of woody plants, but the genetic basis of seed weight in woody plants remain poorly explored. To identify genetic variations and candidate genes responsible for seed weight in natural woody populations, we investigated the hundred-seed weight of 198 paper mulberry individuals from different areas. Our results showed that the hundred-seed weight of paper mulberry was significantly associated with the bioclimatic variables of sampling sites, which increased from south to north along the latitudinal-temperature gradient. Using 2,414,978 high-quality SNPs from re-sequencing data, the genome-wide association analysis of the hundred-seed weight was performed under three models, which identified 148, 19 and 12 associated genes, respectively. Among them, 25 candidate genes were directly hit by the significant SNPs, including the WRKY transcription factor, fatty acid desaturase, F-box protein, etc. Most importantly, we identified three crucial genetic variations in the coding regions of candidate genes (Bp02g2123, Bp01g3291 and Bp10g1642), and significant differences in the hundred-seed weight were detected among the individuals carrying different genotypes. Further analysis revealed that Bp02g2123 encoding a fatty acid desaturase (FAD) might be a key factor affecting the seed weight and local climate adaptation of woody plants. Furthermore, the genome-wide investigation and expression analysis of FAD genes were performed, and the results suggested that BpFADs widely expressed in various tissues and responded to multiple phytohormone and stress treatments. Overall, our study identifies valuable genetic variations and candidate genes, and provides a better understanding of the genetic basis of seed weight in woody plants
Dynamic biotic controls of leaf thermoregulation across the diel timescale
No full textLeaf thermoregulation and consequent leaf-to-air temperature difference (Delta T) are tightly linked to plant metabolic rates and health. Current knowledge mainly focus on the regulation of environmental conditions on Delta T, while an accurate assessment of biotic regulations with field data remains lacking. Here, we used a trait-based model that integrates a coupled photosynthesis-stomatal conductance model with a leaf energy balance model to explore how six leaf traits (i.e. leaf width, emissivity, visible and near-infrared light absorptance, photosynthetic capacity-Vc,max25, and stomatal slope-g1) regulate Delta T variability across the diel timescale. We evaluated the model with field observations collected from temperate to tropical forests. Our results show that: (1) leaf traits mediate large Delta T variability, with the noon-time trait-mediated Delta T variability reaching c. 15.0 degrees C; (2) leaf width, Vc,max25, and g1 are the three most important traits and their relative importance in Delta T regulation varies strongly across the diel timescale; and (3) model-derived trait-Delta T relationships match field observations that were collected close to either midday or midnight. These findings advance our understanding of biotic controls of leaf-level Delta T variability, highlighting a trait-based representation of leaf energy balance that can improve simulations of diverse leaf thermoregulation strategies across species and physiological responses to climate change
