Genome-wide identification of Cymbidium sinense WRKY gene family and the importance of its Group III members in response to abiotic stress

Transcription factors (TFs) of the WRKY family play pivotal roles in defense responses and secondary metabolism of plants. Although WRKY TFs are well documented in numerous plant species, no study has performed a genome-wide investigation of the WRKY gene family in Cymbidium sinense. In the present work, we found 64 C. sinense WRKY (CsWRKY) TFs, and they were further divided into eight subgroups. Chromosomal distribution of CsWRKYs revealed that the majority of these genes were localized on 16 chromosomes, especially on Chromosome 2. Syntenic analysis implied that 13 (20.31%) genes were derived from segmental duplication events, and 17 orthologous gene pairs were identified between Arabidopsis thaliana WRKY (AtWRKY) and CsWRKY genes. Moreover, 55 of the 64 CsWRKYs were detectable in different plant tissues in response to exposure to plant hormones. Among them, Group III members were strongly induced in response to various hormone treatments, indicating their potential essential roles in hormone signaling. We subsequently analyzed the function of CsWRKY18 in Group III. The CsWRKY18 was localized in the nucleus. The constitutive expression of CsWRKY18 in Arabidopsis led to enhanced sensitivity to ABA-mediated seed germination and root growth and elevated plant tolerance to abiotic stress within the ABA-dependent pathway. Overall, our study represented the first genome-wide characterization and functional analysis of WRKY TFs in C. sinense, which could provide useful clues about the evolution and functional description of CsWRKY genes

The Cymbidium genome reveals the evolution of unique morphological traits

The marvelously diverse Orchidaceae constitutes the largest family of angiosperms. The genus Cymbidium in Orchidaceae is well known for its unique vegetation, floral morphology, and flower scent traits. Here, a chromosomescale assembly of the genome of Cymbidium ensifolium (Jianlan) is presented. Comparative genomic analysis showed that C. ensifolium has experienced two whole-genome duplication (WGD) events, the most recent of which was shared by all orchids, while the older event was the τ event shared by most monocots. The results of MADS-box genes analysis provided support for establishing a unique gene model of orchid flower development regulation, and flower shape mutations in C. ensifolium were shown to be associated with the abnormal expression of MADS-box genes. The most abundant floral scent components identified included methyl jasmonate, acacia alcohol and linalool, and the genes involved in the floral scent component network of C. ensifolium were determined. Furthermore, the decreased expression of photosynthesis-antennae and photosynthesis metabolic pathway genes in leaves was shown to result in colorful striped leaves, while the increased expression of MADS-box genes in leaves led to perianth-like leaves. Our results provide fundamental insights into orchid evolution and diversification.The National Key Research and Development Program of China, the National Natural Science Foundation of China, the Outstanding Young Scientific Research Talent Project of Fujian Agriculture and Forestry University, the Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization Construction Funds, and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program.https://www.nature.com/hortresam2022BiochemistryGeneticsMicrobiology and Plant Patholog

High-Density Genetic Linkage Map Construction and QTLs Identification Associated with Four Leaf-Related Traits in Lady’s Slipper Orchids (<i>Paphiopedilum concolor</i> × <i>Paphiopedilum hirsutissimum</i>)

Lady’s slipper orchids (Paphiopedilum spp.) are highly valuable within the flower industry. Recently, both Paphiopedilum concolor and Paphiopedilum hirsutissimum (2n = 2x = 26) have been widely used for hybrid parents, ornamental, and economic purposes. However, high-density genetic maps and leaf traits related to quantitative trait loci (QTLs) in these two Paphiopedilum species have been poorly studied. Herein, an interspecific F1 population of 95 individuals was developed from the cross between P. concolor and P. hirsutissimum with contrasting leaf length (LL), leaf width (LW), leaf thickness (LT), and leaf number (LN). RNA extracted from the F1 population and their parents was subjected to high-throughput RNA sequencing. Approximately 745.59 Gb of clean data were generated, and were assembled into 349,730 transcripts and 185,089 unigenes. In total, 165,196 high-resolution polymorphic single nucleotide polymorphism (SNP) markers were initially identified. Finally, 8410 SNP markers satisfied the requirements and were used to construct a genetic map. The integrated map contained 13 linkage groups (LGs) and spanned 1616.18 cM, with an average distance of 0.19 cM between adjacent markers. QTL analysis in the F1 population identified 12 QTLs linked to four leaf-related traits, including LL, LW, LT, and LN. These QTLs by composition interval mapping, explained 11.86% to 21.58% of the phenotypic variance, and were distributed on eight LGs, but not on LGs 4, 6, 8, 12, and 13. Furthermore, 25 unigenes were identified via BLAST searches between the SNP markers in the QTL regions and our assembled transcriptome, of which 11 unigenes were enriched with 59 gene ontology (GO) terms. The information generated in this study will be useful for candidate genes for further molecular regulation studies on leaf traits, future marker-assisted selection of leaf ornamental improvement breeding, genome assembly, and comparative genome analyses

Complete chloroplast genome of the plant Stahlianthus Involucratus (Zingiberaceae)

The first complete chloroplast genome of Stahlianthus involucratus (Zingiberaceae) was reported in this study. The S. involucratus chloroplast genome was 163,300 bp in length and consisted of one large single copy (LSC) region of 87,498 bp, one small single copy (SSC) region of 15,568 bp, and a pair of inverted repeat (IR) regions 30,117 bp. It encoded 141 genes, including 87 protein-coding genes (79 PCG species), 46 tRNA genes (28 tRNA species) and 8 rRNA genes (4 rRNA species). The phylogenetic analysis based on single nucleotide polymorphisms strongly supported that S. involucratus, Curcuma roscoeana and Curcuma longa formed a cluster in group CurcumaII within family Zingiberaceae

The complete chloroplast genome sequence of Spathiphyllum cannifolium

We reported and characterized the complete nucleotide sequence of the Spathiphyllum cannifolium chloroplast (cp) genome in this study. The circular molecule of the cp genome is 171,420 bp containing a pair of 31,460 bp IR regions, separated by a small single-copy region (SSC) of 16,331 bp and a large single-copy region (LSC) of 92,169 bp, respectively. A total of 132 genes were successfully annotated in the cp genome, including 87 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The G + C content of the whole cp genome is 35.62%, while the LSC, SSC, and IR region are 33.94, 28.02, and 40.05%, respectively

Complete chloroplast genome sequence of Hedychium coronarium

The first complete chloroplast genome of Hedychium coronarium (Zingiberaceae) was reported in this study. The H. coronarium chloroplast genome was 163,949 bp in length and comprised a pair of inverted repeat (IR) regions of 29,780 bp each, a large single-copy (LSC) region of 88,581 bp and a small single-copy (SSC) region of 15,808 bp. It encoded 141 genes, including 87 protein-coding genes (79 PCG species), 46 tRNA genes (28 tRNA species), and eight rRNA genes (four rRNA species). The nucleotide composition was asymmetric (31.68% A, 18.35% C, 17.74% G, 32.23% T) with an overall AT content of 63.92%. Phylogenetic analysis showed that H. coronarium was classified into a monophyletic group within the genus Hedychium in family Zingiberaceae

China's Energy Demand Scenario Analysis in 2030

AbstractIn order to forecast energy demand in China in the next 20 years, this paper firstly analyzes the current situation of China's energy consumption, and then apply LEAP model to simulate primary energy and final energy demand in 2020, 2030 under different scenario composition about economic development, energy efficiency and energy structure. The results show that: the total primary energy demand will reach 4840-5070 Mtce in 2020, 5580-5870 Mtce in 2030; the share of coal in primary energy will decrease, and that of oil, natural gas and non-fossil energy sources will increase. For all the three economic growth scenarios, 40-45% carbon emission intensity reduction target can be realized. If non-fossil energy can be further developed, carbon emission intensity can reduce more than 45% by 2020. The goal of the 15% share of non-fuel energy in primary energy is difficult to realize, unless the most development potentials of hydro power, nuclear power and wind power can be reached

Complete chloroplast genome sequence of Amomum villosum

The first complete chloroplast genome of Amomum villosum (Zingiberaceae) was reported in this study. The A. villosum genome was 163,608 bp in length, and comprised a pair of inverted repeat (IR) regions of 29,820 bp each, a large single-copy (LSC) region of 88,680 bp, and a small single-copy (SSC) region of 15,288 bp. It encoded 141 genes, including 87 protein-coding genes (79 PCG species), 46 tRNA genes (28 tRNA species), and 8 rRNA genes (4 rRNA species). The overall AT content was 63.92%. Phylogenetic analysis showed that A. villosum was closely related to two species Amomum kravanh and Amomum compactum within the genus Amomum in family Zingiberaceae

Complete chloroplast genomes of Zingiber montanum and Zingiber zerumbet: Genome structure, comparative and phylogenetic analyses.

Zingiber montanum (Z. montanum) and Zingiber zerumbet (Z. zerumbet) are important medicinal and ornamental herbs in the genus Zingiber and family Zingiberaceae. Chloroplast-derived markers are useful for species identification and phylogenetic studies, but further development is warranted for these two Zingiber species. In this study, we report the complete chloroplast genomes of Z. montanum and Z. zerumbet, which had lengths of 164,464 bp and 163,589 bp, respectively. These genomes had typical quadripartite structures with a large single copy (LSC, 87,856-89,161 bp), a small single copy (SSC, 15,803-15,642 bp), and a pair of inverted repeats (IRa and IRb, 29,393-30,449 bp). We identified 111 unique genes in each chloroplast genome, including 79 protein-coding genes, 28 tRNAs and 4 rRNA genes. We analyzed the molecular structures, gene information, amino acid frequencies, codon usage patterns, RNA editing sites, simple sequence repeats (SSRs) and long repeats from the two chloroplast genomes. A comparison of the Z. montanum and Z. zerumbet chloroplast genomes detected 489 single-nucleotide polymorphisms (SNPs) and 172 insertions/deletions (indels). Thirteen highly divergent regions, including ycf1, rps19, rps18-rpl20, accD-psaI, psaC-ndhE, psbA-trnK-UUU, trnfM-CAU-rps14, trnE-UUC-trnT-UGU, ccsA-ndhD, psbC-trnS-UGA, start-psbA, petA-psbJ, and rbcL-accD, were identified and might be useful for future species identification and phylogeny in the genus Zingiber. Positive selection was observed for ATP synthase (atpA and atpB), RNA polymerase (rpoA), small subunit ribosomal protein (rps3) and other protein-coding genes (accD, clpP, ycf1, and ycf2) based on the Ka/Ks ratios. Additionally, chloroplast SNP-based phylogeny analyses found that Zingiber was a monophyletic sister branch to Kaempferia and that chloroplast SNPs could be used to identify Zingiber species. The genome resources in our study provide valuable information for the identification and phylogenetic analysis of the genus Zingiber and family Zingiberaceae