Polar zooplankton are particularly sensitive to climate change, and have been used as rapid-responders to indicate climate-induced changes in the fragile Antarctic ecosystem. DNA barcoding provides an alternative appr...Polar zooplankton are particularly sensitive to climate change, and have been used as rapid-responders to indicate climate-induced changes in the fragile Antarctic ecosystem. DNA barcoding provides an alternative approach for rapid zooplankton species identification. Ninety-four specimens belonging to 32 Antarctic zooplankton species were barcoded to construct a compre- hensive reference library. An 830 to 1 050 base-pair region of the mitochondrial cytochrome c oxidase subunit I （mtCOI） gene was obtained as DNA barcodes. The intraspecific variation of the gene ranged from 0 to 2.6% （p-distance）, with an average of 0.67% （SD=0.67%）. The distance between species within the same genera ranged from 0.1% （Calanus） to 29.3%, with an average of 15.3% （SD=8.4%）. The morphological and genetic similarities between Calanus propinquus and C. simillimus raise new questions about the taxonomic status of C. simillimus. With the exception of the two Calanus species, the intraspecific genetic divergence was much smaller than the interspecific divergence among congeneric species, confirming the existence of a barcode gap for Ant- arctic zooplankton. In addition, species other than Calanus sp. formed a monophyletic group. Therefore, we have confirmed DNA barcoding as an accurate and efficient approach for zooplankton identification in the Antarctic area （except for Hydromedusa, Tu- nicata, and other gelatinous zooplankton）. Indicator vector analysis further confirmed this conclusion. The new primer sets issued here may facilitate the study of Antarctic marine zooplankton species composition by environmental metagenetic analysis.展开更多
Background： The SWEET （Sugars will eventually be exported transporters） gene family plays multiple roles in plant physiological activities and development process. It participates in reproductive development and in...Background： The SWEET （Sugars will eventually be exported transporters） gene family plays multiple roles in plant physiological activities and development process. It participates in reproductive development and in the process of sugar transport and absorption, plant senescence and stress responses and plant-pathogen interaction. However, thecomprehensive analysis of SWEET genes has not been reported in cotton. Results： In this study, we identified 22, 31, 55 and 60 SWEETgenes from the sequenced genomes of Gossypium orboreum, G. rairnondii, G. hirsutum and G. borbadense, respectively. Phylogenetic tree analysis showed that the SWEET genes could be divided into four groups, which were further classified into 14 sub-clades. Further analysis of chromosomal location, synteny analysis and gene duplication suggested that the orthologs showed a good collinearity and segmental duplication events played a crucial role in the expansion of the family in cotton. Specific MtN3_slv domains were highly conserved between Arabidopsis and cotton by exon-intron organization and motif analysis. In addition, the expression pattern in different tissues indicated that the duplicated genes in cotton might have acquired new functions as a result of sub-functionalization or neo-functionalization. The expression pattern of SWEET genes showed that the different genes were induced by diverse stresses. The identification and functional analysis of SWEET genes in cotton may provide more candidate genes for genetic modification. Conclusion： SWEET genes were classified into four clades in cotton. The expression patterns suggested that the duplicated genes might have experienced a functional divergence. This work provides insights into the evolution of SWEETgenes and more candidates for specific genetic modification, which will be useful in future research.展开更多
基金supported by the Chinese Polar Environment Comprehensive Investigation & Assessment Programmes (Grant no.CHINARE2013-01-05)the Institute of Oceanology,Chinese Academy of Sciences (IOCAS) Funding (Grant no.2012IO060102)
文摘Polar zooplankton are particularly sensitive to climate change, and have been used as rapid-responders to indicate climate-induced changes in the fragile Antarctic ecosystem. DNA barcoding provides an alternative approach for rapid zooplankton species identification. Ninety-four specimens belonging to 32 Antarctic zooplankton species were barcoded to construct a compre- hensive reference library. An 830 to 1 050 base-pair region of the mitochondrial cytochrome c oxidase subunit I （mtCOI） gene was obtained as DNA barcodes. The intraspecific variation of the gene ranged from 0 to 2.6% （p-distance）, with an average of 0.67% （SD=0.67%）. The distance between species within the same genera ranged from 0.1% （Calanus） to 29.3%, with an average of 15.3% （SD=8.4%）. The morphological and genetic similarities between Calanus propinquus and C. simillimus raise new questions about the taxonomic status of C. simillimus. With the exception of the two Calanus species, the intraspecific genetic divergence was much smaller than the interspecific divergence among congeneric species, confirming the existence of a barcode gap for Ant- arctic zooplankton. In addition, species other than Calanus sp. formed a monophyletic group. Therefore, we have confirmed DNA barcoding as an accurate and efficient approach for zooplankton identification in the Antarctic area （except for Hydromedusa, Tu- nicata, and other gelatinous zooplankton）. Indicator vector analysis further confirmed this conclusion. The new primer sets issued here may facilitate the study of Antarctic marine zooplankton species composition by environmental metagenetic analysis.
基金supported by the The National Key ResearchDevelopment Program of China(2016YFD0101400,2017YFD0101600)
文摘Background： The SWEET （Sugars will eventually be exported transporters） gene family plays multiple roles in plant physiological activities and development process. It participates in reproductive development and in the process of sugar transport and absorption, plant senescence and stress responses and plant-pathogen interaction. However, thecomprehensive analysis of SWEET genes has not been reported in cotton. Results： In this study, we identified 22, 31, 55 and 60 SWEETgenes from the sequenced genomes of Gossypium orboreum, G. rairnondii, G. hirsutum and G. borbadense, respectively. Phylogenetic tree analysis showed that the SWEET genes could be divided into four groups, which were further classified into 14 sub-clades. Further analysis of chromosomal location, synteny analysis and gene duplication suggested that the orthologs showed a good collinearity and segmental duplication events played a crucial role in the expansion of the family in cotton. Specific MtN3_slv domains were highly conserved between Arabidopsis and cotton by exon-intron organization and motif analysis. In addition, the expression pattern in different tissues indicated that the duplicated genes in cotton might have acquired new functions as a result of sub-functionalization or neo-functionalization. The expression pattern of SWEET genes showed that the different genes were induced by diverse stresses. The identification and functional analysis of SWEET genes in cotton may provide more candidate genes for genetic modification. Conclusion： SWEET genes were classified into four clades in cotton. The expression patterns suggested that the duplicated genes might have experienced a functional divergence. This work provides insights into the evolution of SWEETgenes and more candidates for specific genetic modification, which will be useful in future research.
