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25 May 2022, Volume 44 Issue 03
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  • Articles
    Diversity patterns of cushion plants on the Qinghai-Tibet Plateau: A basic study for future conservation efforts on alpine ecosystems
    Ya-Zhou Zhang, Li-Shen Qian, Xu-Fang Chen, Lu Sun, Hang Sun, Jian-Guo Chen
    2022, 44(03):  231-242.  doi:10.1016/j.pld.2021.09.001
    Abstract ( 46 )   HTML ( )   PDF (15341KB) ( 66 )   Save
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    The Qinghai-Tibet Plateau (QTP) is an important cushion plant hotspot. However, the distribution of cushion plants on the QTP is unknown, as are the factors that drive cushion plant distribution, limiting our understanding of the evolution of cushion species in the region. In this study, we assessed spatial patterns of total cushion plant diversity (including taxonomic and phylogenetic) over the entire QTP and compared patterns of diversity of cushion plants with different typologies (i.e., compact vs. loose). We also examined how these patterns were related to climatic features. Our results indicate that the southern QTP hosts the highest total cushion plant richness, especially in the south-central Hengduan Mountains subregion. The total number of cushion species declines from south to north and from southeast to northwest. Compact cushion plants exhibit similar patterns as the total cushion plant richness, whereas loose cushion plants show random distribution. Cushion plant phylogenetic diversity showed a similar pattern as that of the total cushion plant richness. In addition, cushion plant phylogenetic community structure was clustered in the eastern and southwestern QTP, whereas random or overdispersed in other areas. Climatic features represented by annual energy and water trends, seasonality and extreme environmental factors, had significant effects on cushion plant diversity patterns but limited effects on the phylogenetic community structure, suggesting that climatic features indeed promote the formation of cushion plants. Because cushion plants play vital roles in alpine ecosystems, our findings not only promote our understanding of the evolution and formation of alpine cushion plant diversity but also provide an indispensable foundation for future studies on cushion plant functions and thus alpine ecosystem sustainability in the entire QTP region.
    Assessing the effectiveness of community managed forests for plant diversity conservation in Meghalaya, Northeast India
    Aabid Hussain Mir, Kiranmay Sarma, Krishna Upadhaya
    2022, 44(03):  243-254.  doi:10.1016/j.pld.2021.11.010
    Abstract ( 18 )   HTML ( )   PDF (5703KB) ( 3 )   Save
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    In the state Meghalaya, northeast India, >80% of the forest lands are owned by local communities and managed by traditional institutions. These forests are under severe threats due to a number of human disturbances. The present study was conducted to assess the plant diversity and identify the community forests for priority conservation in Khasi Hills of Meghalaya. Floristic explorations carried out in the 87 forests reveals the presence of 1300 plant species of which 400 are either rare, endemic or threatened. Of the different forest categories, reserve forests had the highest number of species (1190), followed by sacred forests (987 species) and village forests (786 species). Majority of the forests (56) had high-species richness, irreplaceability level (42 forests) and vulnerability level (54). In terms of area, 13.8% (1666.8?ha) fall under low risk while 1855?ha under high risk zone. High risk zone was mostly represented by village forests. An area of 7661.56?ha of community forests falls under high priority category and hence calls for immediate conservation actions. The conservation priority map generated in the present study will help to concentrate the protection strategy to the demarcated and adjoining areas and help conservationists and planners to evolve effective strategies for conservation of the community forests.
    Distribution patterns and industry planning of commonly used traditional Chinese medicinal plants in China
    Zhang-Jian Shan, Jian-Fei Ye, Da-Cheng Hao, Pei-Gen Xiao, Zhi-Duan Chen, An-Ming Lu
    2022, 44(03):  255-261.  doi:10.1016/j.pld.2021.11.003
    Abstract ( 37 )   HTML ( )   PDF (3717KB) ( 20 )   Save
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    Medicinal plants are the primary material basis for disease prevention and treatment in traditional Chinese medicine (TCM). The conservation and sustainable utilization of these medicinal plants is critical for the development of the TCM industry. However, wild medicinal plant resources have sharply declined in recent decades. To ameliorate the shortage of medicinal plant resources, it is essential to explore the development potential of the TCM industry in different geographical regions. For this purpose, we examined the spatial distribution of commonly used medicinal plants in China, the number of Chinese medicinal material markets, and the number of TCM decoction piece enterprises. Specifically, multispecies superimposition analysis and Thiessen polygons were used to reveal the optimal range for planting bulk medicinal plants and the ideal regions for building Chinese medicinal material markets, respectively. Furthermore, we quantitatively analyzed mismatches between the spatial distribution of commonly used medicinal plant richness, Chinese medicinal material markets, and TCM decoction piece enterprises. We found that?the areas suitable for growing commonly used medicinal plants in China were mainly distributed in Hengduan Mountain, Nanling Mountain, Wuling Mountain, and Daba Mountain areas. The Thiessen polygon network based on Chinese medicinal material market localities showed there are currently fewer markets in southwestern, northwestern, and northeastern China than in central and southern China. TCM decoction piece enterprises are concentrated in a few provinces, such as Hebei and Jiangxi. We found that the distribution of commonly used medicinal plants, Chinese medicinal material markets and TCM decoction piece enterprises are mismatched in Henan, Shaanxi, Hunan, Hubei, Zhejiang, Fujian, Chongqing, and Xizang. We recommend strengthening development of the TCM industry in Henan, Hunan, Zhejiang, Shaanxi, Hubei, Chongqing, Fujian, and Xizang; building more Chinese medicinal material markets in southwestern, northwestern, and northeastern China; and establishing medicinal plant nurseries in resource-rich provinces to better protect and domesticate local medicinal plants.
    Lycophyte transcriptomes reveal two whole-genome duplications in Lycopodiaceae: Insights into the polyploidization of Phlegmariurus
    Zeng-Qiang Xia, Zuo-Ying Wei, Hui Shen, Jiang-Ping Shu, Ting Wang, Yu-Feng Gu, Amit Jaisi, Yue-Hong Yan
    2022, 44(03):  262-270.  doi:10.1016/j.pld.2021.08.004
    Abstract ( 26 )   HTML ( )   PDF (8607KB) ( 7 )   Save
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    Lycophytes are an ancient clade of the non-flowering vascular plants with chromosome numbers that vary from tens to hundreds. They are an excellent study system for examining whole-genome duplications (WGDs), or polyploidization, in spore-dispersed vascular plants. However, a lack of genome sequence data limits the reliable detection of very ancient WGDs, small-scale duplications (SSDs), and recent WGDs. Here, we integrated phylogenomic analysis and the distribution of synonymous substitutions per synonymous sites (Ks) of the transcriptomes of 13 species of lycophytes to identify, locate, and date multiple WGDs in the lycophyte family Lycopodiaceae. Additionally, we examined the genus Phlegmariurus for signs of genetic discordance, which can provide valuable insight into the underlying causes of such conflict (e.g., hybridization, incomplete lineage sorting, or horizontal gene transfer).We found strong evidence that two WGD events occurred along the phylogenetic backbone of Lycopodiaceae, with one occurring in the common ancestor of extant Phlegmariurus (Lycopodiaceae) approximately 22–23 million years ago (Mya) and the other occurring in the common ancestor of Lycopodiaceae around 206–214 Mya. Interestingly, we found significant genetic discordance in the genus Phlegmariurus, indicating that the genus has a complex evolutionary history. This study provides molecular evidence for multiple WGDs in Lycopodiaceae and offers phylogenetic clues to the evolutionary history of Lycopodiaceae.
    Adaptive genetic diversity of dominant species contributes to species co-existence and community assembly
    Qiao-Ming Li, Chao-Nan Cai, Wu-Mei Xu, Min Cao, Li-Qing Sha, Lu-Xiang Lin, Tian-Hua He
    2022, 44(03):  271-278.  doi:10.1016/j.pld.2021.11.002
    Abstract ( 23 )   HTML ( )   PDF (946KB) ( 8 )   Save
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    The synthesis of evolutionary biology and community ecology aims to understand how genetic variation within one species can shape community properties and how the ecological properties of a community can drive the evolution of a species. A rarely explored aspect is whether the interaction of genetic variation and community properties depends on the species' ecological role. Here we investigated the interactions among environmental factors, species diversity, and the within-species genetic diversity of species with different ecological roles. Using high-throughput DNA sequencing, we genotyped a canopy-dominant tree species, Parashorea chinensis, and an understory-abundant species, Pittosporopsis kerrii, from fifteen plots in Xishuangbanna tropical seasonal rainforest and estimated their adaptive, neutral and total genetic diversity; we also surveyed species diversity and assayed key soil nutrients. Structural equation modelling revealed that soil nitrogen availability created an opposing effect in species diversity and adaptive genetic diversity of the canopy-dominant Pa. chinensis. The increased adaptive genetic diversity of Pa. chinensis led to greater species diversity by promoting co-existence. Increased species diversity reduced the adaptive genetic diversity of the dominant understory species, Pi. kerrii, which was promoted by the adaptive genetic diversity of the canopy-dominant Pa. chinensis. However, such relationships were absent when neutral genetic diversity or total genetic diversity were used in the model. Our results demonstrated the important ecological interaction between adaptive genetic diversity and species diversity, but the pattern of the interaction depends on the identity of the species. Our results highlight the significant ecological role of dominant species in competitive interactions and regulation of community structure.
    Molecular phylogenetic analyses based on the complete plastid genomes and nuclear sequences reveal Daphne (Thymelaeaceae) to be non-monophyletic as current circumscription
    Shiou Yih Lee, Ke-Wang Xu, Cui-Ying Huang, Jung-Hyun Lee, Wen-Bo Liao, Yong-Hong Zhang, Qiang Fan
    2022, 44(03):  279-289.  doi:10.1016/j.pld.2021.11.001
    Abstract ( 29 )   HTML ( )   PDF (10468KB) ( 21 )   Save
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    The diverse members of the genus Daphne are prized for their fragrant flowers. Despite being promising ornamental plants in many countries, genetic information of Daphne is scarce. In this study, the plastomes of four species and one variety of Daphne were sequenced and analyzed. The plastomes were typical and contained a pair of inverted repeat (IR) regions that separated the large single-copy (LSC) region from the small single-copy (SSC) region. With a length ranging from 132,869 bp (D.?genkwa) to 174,773 bp (D. championii), 106 to 141 genes were predicted. Comparative plastome analysis of the newly sequenced plastomes with four publicly available Daphne plastomes identified an expansion of the IRs, sequence variations, and mutational hotspots. Phylogenetic analyses indicated that the genus Daphne in its current circumscription is polyphyletic. Daphne genkwa was nested within the genus Wikstroemia, while D.?championii was well resolved as sister to Edgeworthia. These findings concurred with results from our study that used nuclear ribosomal internal transcribed spacer sequence data. The conflicts on the molecular placement of D.?championii and D.?genkwa and the present taxonomic classification in Daphne suggest that a new intergeneric classification system of Daphneae warrants consideration.
    Multiple lines of evidence supports the two varieties of Halenia elliptica (Gentianaceae) as two species
    Jin-Feng Wu, Dong-Rui Jia, Rui-Juan Liu, Zhi-Li Zhou, Lin-Lin Wang, Min-Yu Chen, Li-Hua Meng, Yuan-Wen Duan
    2022, 44(03):  290-299.  doi:10.1016/j.pld.2021.09.004
    Abstract ( 25 )   HTML ( )   PDF (2441KB) ( 17 )   Save
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    Delimiting species requires multiple sources of evidence. Here, we delimited two varieties of Halenia elliptica (Gentianaceae) using several lines of evidence, including morphological traits and mating system in a sympatric population, phylogenetic relationships based on nrITS and cpDNA (rpl16) data, and complete chloroplast genome sequences. Comparative analysis of 21 morphological traits clearly separates the two varieties of H.?elliptica. Examination of the flowering process and pollination treatments indicate that H.?elliptica var. grandiflora produces seeds via outcrossing, whereas H.?elliptica var. elliptica produces seeds via mixed mating. Furthermore, hand-pollinated hybridization of the two varieties produced no seeds. Observations of pollinators showed that when bees began a pollination bout on H.?elliptica var. grandiflora they preferred to continue pollinating this variety; however, when they began a pollination bout on H.?elliptica var. elliptica, they showed no preference for either variety. Phylogenetic analysis confirmed the monophyly of H.?elliptica, which was further divided into two monophyletic clades corresponding to the two varieties. A large number of variants from the chloroplast genomes reflected remarkable genetic dissimilarities between the two varieties of H.?elliptica. We recommend that the two varieties of H.?elliptica should be revised as two species (H.?elliptica and H. grandiflora). Our findings indicate that H.?elliptica varieties may have split into two separate species due to a shift in mating system, changes in flowering phenology and/or post-pollination reproductive isolation.
    Short communication
    Ceratopteris chunii and Ceratopteris chingii (Pteridaceae), two new diploid species from China, based on morphological, cytological, and molecular data
    Jun-Hao Yu, Rui Zhang, Qiao-Ling Liu, Fa-Guo Wang, Xun-Lin Yu, Xi-Ling Dai, Yong-Bo Liu, Yue-Hong Yan
    2022, 44(03):  300-307.  doi:10.1016/j.pld.2021.10.002
    Abstract ( 24 )   HTML ( )   PDF (12203KB) ( 16 )   Save
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    Understanding how natural hybridization and polyploidizations originate in plants requires identifying potential diploid ancestors. However, cryptic plant species are widespread, particularly in Ceratopteris (Pteridaceae). Identifying Ceratopteris cryptic species with different polyploidy levels is a challenge because Ceratopteris spp. exhibit high degrees of phenotypic plasticity. Here, two new cryptic species of Ceratopteris, Ceratopteris chunii and Ceratopteris chingii, are described and illustrated. Phylogenetic analyses reveal that each of the new species form a well-supported clade. C.?chunii and C.?chingii are similar to Ceratopteris gaudichaudii var. vulgaris and C. pteridoides, respectively, but distinct from their relatives in the stipe, basal pinna of the sterile leaf or subelliptic shape of the fertile leaf, as well as the spore surface. In addition, chromosome studies indicate that C.?chunii and C.?chingii are both diploid. These findings will help us further understand the origin of Ceratopteris polyploids in Asia.
    Articles
    Germplasm resources of three wood plant species enriched with nervonic acid
    Xing He, Tian-Quan Lu, Jiang-Ying Li, Ping Mao, Li Zhang, Guo-Wei Zheng, Bo Tian
    2022, 44(03):  308-315.  doi:10.1016/j.pld.2022.01.004
    Abstract ( 24 )   HTML ( )   PDF (20965KB) ( 2 )   Save
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    Nervonic acid (NA) is a very-long-chain monounsaturated fatty acid with pharmaceutical and nutraceutical functions that plays an important role in treating several neurological disorders. One major source of NA is plant seed oil. Here we report fatty acid profiles of seeds and germplasm diversity of six plant species, including three woody plants with high amounts of NA-enriched seed oil, Malania oleifera, Macaranga adenantha, and M. indica. M. oleifera had the largest seed (average 7.40?g single seed), highest oil content (58.71%), and highest NA level (42.22%). The germplasm diversity of M. oleifera is associated with its habitat but not elevation. Seeds of M. adenantha contained higher NA levels (28.41%) than M.?indica (21.77%), but M.?indica contained a significantly higher oil content (29.22%) and seed yield. M.?adenantha germplasm varied among populations, with one population having seeds with high oil content (22.63%) and NA level (37.78%).Although M.?indica grow naturally at a range of elevations, no significant differences were detected between M.?indica populations. These results suggest that M. indica and M. oleifera have greater potential as a source of NA, which will contribute to constructing a germplasm resource nursery and establishing a selection and breeding program to improve the development of NA-enriched plants.
    Plastid RNA editing reduction accompanied with genetic variations in Cymbidium, a genus with diverse lifestyle modes
    Mengqing Zhe, Le Zhang, Fang Liu, Yiwei Huang, Weishu Fan, Junbo Yang, Andan Zhu
    2022, 44(03):  316-321.  doi:10.1016/j.pld.2021.07.002
    Abstract ( 19 )   HTML ( )   PDF (2028KB) ( 4 )   Save
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    Recent sequencing efforts have broadly uncovered the evolutionary trajectory of plastid genomes (plastomes) of flowering plants in diverse habitats, yet our knowledge of the evolution of plastid posttranscriptional modifications is limited. In this study, we generated 11 complete plastomes and performed ultra-deep transcriptome sequencing to investigate the co-evolution of plastid RNA editing and genetic variation in Cymbidium, a genus with diverse trophic lifestyles. Genome size and gene content is reduced in terrestrial and green mycoheterotrophic orchids relative to their epiphytic relatives. This could be partly due to extensive losses and pseudogenization of ndh genes for the plastid NADH dehydrogenase-like complex, but independent pseudogenization of ndh genes has also occurred in the epiphyte C.?mannii, which was reported to use strong crassulacean acid metabolism photosynthesis. RNA editing sites are abundant but variable in number among Cymbidium plastomes. The nearly twofold variation in editing abundance is mainly due to extensive reduction of ancestral editing sites in ndh transcripts of terrestrial, mycoheterotrophic, and C.?mannii plastomes. The co-occurrence of editing reduction and pseudogenization in ndh genes suggests functional constraints on editing machinery may be relaxed, leading to nonrandom loss of ancestral edited sites via reduced editing efficiency. This study represents the first systematic examination of RNA editing evolution linked to plastid genome variation in a single genus. We also propose an explanation for how genomic and posttranscriptional variations might be affected by lifestyle-associated ecological adaptation strategies in Cymbidium.
    Transcriptome and carotenoid profiling of different varieties of Coffea arabica provides insights into fruit color formation
    Faguang Hu, Xiaofei Bi, Hongming Liu, Xingfei Fu, Yanan Li, Yang Yang, Xiaofang Zhang, Ruirui Wu, Guiping Li, Yulan Lv, Jiaxiong Huang, Xinping Luo, Rui Shi
    2022, 44(03):  322-334.  doi:10.1016/j.pld.2021.11.005
    Abstract ( 13 )   HTML ( )   PDF (11291KB) ( 3 )   Save
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    The processability and ultimate quality of coffee (Coffea?arabica) are determined by the composition of the matured fruits. The basis of genetic variation in coffee fruit quality could be explained by studying color formation during fruit maturation. Transcriptome profiling was conducted on matured fruits of four C.?arabica varieties (orange colored fruits (ORF); purple colored fruits (PF); red colored fruits (RF) and yellow colored fruits (YF)) to identify key color-regulating genes, biosynthesis pathways and transcription factors implicated in fruit color formation. A total of 39,938 genes were identified in the transcriptomes of the four C.?arabica varieties. In all, 2745, 781 and 1224 differentially expressed genes (DEGs) were detected in YF_vs_PF, YF_vs_RF and YF_vs_ORF, respectively, with 1732 DEGs conserved among the three pairwise groups. Functional annotation of the DEGs led to the detection of 28 and 82 key genes involved in the biosynthesis of carotenoids and anthocyanins, respectively. Key transcription factors bHLH, MYB, NAC, MADS, and WRKY implicated in fruit color regulation were detected. The high expression levels of gene-LOC113688784 (PSY), gene-LOC113730013 (β-CHY), gene-LOC113728842 (CCD7), gene-LOC113689681 (NCED) and gene-LOC113729473 (ABA2) in YF may have accounted for the yellow coloration. The differential expression of several anthocyanin and carotenoid-specific genes in the fruits substantially account for the purple (PF), red (RF), and orange (ORF) colorations. This study provides important insights into fruit color formation and variations in C.?arabica and will help to develop coffee varieties with specific color and quality traits.