121 research outputs found

    AaABF3, an Abscisic Acid–Responsive Transcription Factor, Positively Regulates Artemisinin Biosynthesis in Artemisia annua

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    Artemisinin is well known for its irreplaceable curative effect on the devastating parasitic disease, Malaria. This sesquiterpenoid is specifically produced in Chinese traditional herbal plant Artemisia annua. Earlier studies have shown that phytohormone abscisic acid (ABA) plays an important role in increasing the artemisinin content, but how ABA regulates artemisinin biosynthesis is still poorly understood. In this study, we identified that AaABF3 encoded an ABRE (ABA-responsive elements) binding factor. qRT-PCR analysis showed that AaABF3 was induced by ABA and expressed much higher in trichomes where artemisinin is synthesized and accumulated. To further investigate the mechanism of AaABF3 regulating the artemisinin biosynthesis, we carried out dual-luciferase analysis, yeast one-hybrid assay and electrophoretic mobility shift assay. The results revealed that AaABF3 could directly bind to the promoter of ALDH1 gene, which is a key gene in artemisinin biosynthesis, and activate the expression of ALDH1. Functional analysis revealed that overexpression of AaABF3 in A. annua enhanced the production of artemisinin, while RNA interference of AaABF3 resulted in decreased artemisinin content. Taken together, our results demonstrated that AaABF3 played an important role in ABA-regulated artemisinin biosynthesis through direct regulation of artemisinin biosynthesis gene, ALDH1

    The water lily genome and the early evolution of flowering plants

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    Water lilies belong to the angiosperm order Nymphaeales. Amborellales, Nymphaeales and Austrobaileyales together form the so-called ANA-grade of angiosperms, which are extant representatives of lineages that diverged the earliest from the lineage leading to the extant mesangiosperms1–3. Here we report the 409-megabase genome sequence of the blue-petal water lily (Nymphaea colorata). Our phylogenomic analyses support Amborellales and Nymphaeales as successive sister lineages to all other extant angiosperms. The N. colorata genome and 19 other water lily transcriptomes reveal a Nymphaealean whole-genome duplication event, which is shared by Nymphaeaceae and possibly Cabombaceae. Among the genes retained from this whole-genome duplication are homologues of genes that regulate flowering transition and flower development. The broad expression of homologues of floral ABCE genes in N. colorata might support a similarly broadly active ancestral ABCE model of floral organ determination in early angiosperms. Water lilies have evolved attractive floral scents and colours, which are features shared with mesangiosperms, and we identified their putative biosynthetic genes in N. colorata. The chemical compounds and biosynthetic genes behind floral scents suggest that they have evolved in parallel to those in mesangiosperms. Because of its unique phylogenetic position, the N. colorata genome sheds light on the early evolution of angiosperms.Supplementary Tables: This file contains Supplementary Tables 1-21.National Natural Science Foundation of China, the open funds of the State Key Laboratory of Crop Genetics and Germplasm Enhancement (ZW201909) and State Key Laboratory of Tree Genetics and Breeding, the Fujian provincial government in China, the European Union Seventh Framework Programme (FP7/2007-2013) under European Research Council Advanced Grant Agreement and the Special Research Fund of Ghent University.http://www.nature.com/naturecommunicationsam2021BiochemistryGeneticsMicrobiology and Plant Patholog

    An ultimatum game with probabilistic role swapping : an experimental analysis

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    The proposers’ and recipients’ behaviors in the ultimatum game can be affected by various factors, such as participation cost, time constraint, stake size, etc. Another possible element can be role swapping which involves the change of dominant/non-dominant positions between two subjects. An experiment conducted by Weg and Smith (1993) suggested that the proposers proposed higher offer when role swapping was involved. However, no experiment to date has been done to formally study its influence. This study investigated the effect of role swapping probability in a modified standard ultimatum game and three “discrete” ultimatum games where proposers were subject to two splits only. The experiment results indicate that with higher role swapping probability, proposers will increase the offer amount and recipients will also demand more, which implies fairer outcomes for both sides.Bachelor of Art

    Effect of Flavonoid Dynamic Changes on Flower Coloration of <i>Tulipa gesneiana</i> ‘Queen of Night’ during Flower Development

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    Tulipa gesneriana has rich cultivars with abundant flower colors; among them, black tulips have become precious cultivars for their rareness in nature. It is of great significance to understand its color formation mechanism for breeding new cultivars with a blackish flower color in the future. In this present study, petals at five developmental stages of Tulipa gesneriana ‘Queen of Night’ (shorted for ‘QN’), a typical black tulip cultivar, were collected to identity the flavonoid composition and compare the accumulation along with the flower development process, aiming to explore the metabolic mechanism of its flower coloration. By using UPLC-Q-TOF-MS, three anthocyanins and nineteen anthoxanthins (including eighteen flavonols and one flavone) were detected in the petals of ‘QN’. The anthocyanins were identified as delphinidin 3-o-rutinoside, cyanidin 3-o-rutinoside and pelargonidin 3-o-rutinoside, respectively. The main flavonols were identified as quercetin, kaempferol, isorhamnetin, naringin and their glycosides. The only one flavone substance was identified as an apigenin derivative. By comparing the content, anthocyanins were the most abundant substance in the petals of ‘QN’, and showed obvious regularity in the development process. With the flower opening, the anthocyanin content accumulated continuously, and reached the highest level at 3575.9 ÎŒg·g−1·FW at S5, accounting for 80% of the total flavonoids. Among them, delphinidin 3-o-rutinoside and cyanidin 3-o-rutinoside made the main contribution to the coloration of ‘QN’. The content of anthoxanthins increased first and then decreased, reaching the highest to 1114.8 ÎŒg·g−1·FW at S3. Quercetin and its glycosides were the most important flavonol substances in the petals of ‘QN’, accounting for more than 60% of the total anthoxanthins in the five stages. The content of a flavone identified was extremely low, suggesting a limited role in the flower color of ‘QN’. Taken together, the flower color presentation of ‘QN’ was closely related to the composition and accumulation of anthocyanins and flavonols; anthocyanins were the main substances that determine the petal coloration of ‘QN’, and the high content of flavonols played a role of co-pigmentation with these anthocyanins

    Lignosulfonate-Assisted Synthesis of Porous Carbon-Supported MnO<sub>2</sub> Composites with Reinforced Interface Bonding for High-Performance Asymmetric Supercapacitors

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    Carbon/transition metal oxide composites exhibit promising potential as electrode materials for energy storage, but regulating their interfacial composite structures remains a formidable challenge. In this work, we develop a lignosulfonate-assisted synthesis strategy to fabricate a porous carbon-supported MnO2 composite (LSC/MnO2-2) with a robust interface for asymmetric supercapacitors (ASCs). The functionalized lignin porous carbon, achieved through π–π interactions with lignosulfonate, exhibited improved dispersibility, thereby facilitating the deposition of MnO2 onto the carbon matrix. Consequently, LSC/MnO2-2 demonstrates uniform MnO2 loading and enhanced interfacial bonding. The robust interaction between Mn sites and the lignosulfonate-functionalized carbon substrate can promote electron transfer and ion transfer kinetics, effectively activating the electrochemical activity of MnO2. The as-prepared LSC/MnO2-2 demonstrates high specific capacitances of 750 F/g at 0.5 A/g and 400 F/g at 10.0 A/g in a 1 M KOH electrolyte. Furthermore, the assembled ASC exhibits an outstanding energy density of 54.4 Wh/kg at 998.2 W/kg and excellent cyclic stability (94.7% retention over 10,000 cycles at 2.0 A/g). This study presents an alternative method to precisely control the deposition of metal oxides onto carbon materials, aiming to enhance the performance of carbon composites

    Demystifying and Mitigating Code-Dependent Switching Distortions in Current-Steering DACs

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    Attention-Based Deep Multiple-Instance Learning for Classifying Circular RNA and Other Long Non-Coding RNA

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    Circular RNA (circRNA) is a distinguishable circular formed long non-coding RNA (lncRNA), which has specific roles in transcriptional regulation, multiple biological processes. The identification of circRNA from other lncRNA is necessary for relevant research. In this study, we designed attention-based multi-instance learning (MIL) network architecture fed with a raw sequence, to learn the sparse features of RNA sequences and to accomplish the circRNAs identification task. The model outperformed the state-of-art models. Moreover, following the validation of the attention mechanism effectiveness by the handwritten digit dataset, the key sequence loci underlying circRNA’s recognition were obtained based on the corresponding attention score. Then, motif enrichment analysis identified some of the key motifs for circRNA formation. In conclusion, we designed deep learning network architecture suitable for learning gene sequences with sparse features and implemented it for the circRNA identification task, and the model has strong representation capability in the indication of some key loci

    Roles of MPBQ-MT in Promoting α/γ-Tocopherol Production and Photosynthesis under High Light in Lettuce

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    <div><p>2-methyl-6-phytyl-1, 4-benzoquinol methyltransferase (MPBQ-MT) is a vital enzyme catalyzing a key methylation step in both α/Îł-tocopherol and plastoquinone biosynthetic pathway. In this study, the gene encoding MPBQ-MT was isolated from lettuce (<i>Lactuca sativa</i>) by rapid amplification of cDNA ends (RACE), named <i>LsMT</i>. Overexpression of <i>LsMT</i> in lettuce brought about a significant increase of α- and Îł-tocopherol contents with a reduction of phylloquinone (vitamin K1) content, suggesting a competition for a common substrate phytyl diphosphate (PDP) between the two biosynthetic pathways. Besides, overexpression of <i>LsMT</i> significantly increased plastoquinone (PQ) level. The increase of tocopherol and plastoquinone levels by <i>LsMT</i> overexpression conduced to the improvement of plants’ tolerance and photosynthesis under high light stress, by directing excessive light energy toward photosynthetic production rather than toward generation of more photooxidative damage. These findings suggest that the role and function of <i>MPBQ-MT</i> can be further explored for enhancing vitamin E value, strengthening photosynthesis and phototolerance under high light in plants.</p></div
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