In the field of phylogenetic analyses, the rbcL gene encoded large subunit Ribulose-1,5-biphosphate carboxylase/oxygenase （Rubisco, EC4.1.1.39）, which plays a crucial role in the process of photosynthesis for most ...In the field of phylogenetic analyses, the rbcL gene encoded large subunit Ribulose-1,5-biphosphate carboxylase/oxygenase （Rubisco, EC4.1.1.39）, which plays a crucial role in the process of photosynthesis for most terrestrial plants, has been considered to be conserved; however, recent controversy regarding rbcL conservation has appeared since it was proposed to be under natural selection within all principal lineages of land plants. In this study, by examining the variation of DNA and protein sequences among 17 species in the family Tamaricaceae, three nonsynonymous mutations were identified to be under positive selection. The favored sites were located in the alph-helix domains of Rubisco, with decreased hydrophobicity and increased entropy, which could facilitate C〇 2 penetration into the active site of Rubisco. We also found that the expression level of rbcL in different genotypes of Reaumuria soongarica shifted in response to various stresses such as drought, temperature, salt, and light. This study not only sheds light on the functional/structural features of Rubisco in the evolution scenarios from 〇 3-like into C4 in Tamaricaceae but also provides useful information on directing genetic performance to enhance photosynthesis efficiency of desert plants for sustaining fragile desert ecosystems; fur-thermore, it promotes the ability to cope with desert aridification and global warming.展开更多
Tamarix species are small trees that grow in various natural habitats and have a wide geographic distribution.Microfungal species previously found on Tamarix and recently collected in Italy and Russia were identified ...Tamarix species are small trees that grow in various natural habitats and have a wide geographic distribution.Microfungal species previously found on Tamarix and recently collected in Italy and Russia were identified based on morphological characters and analyses of gene sequence data.The sexual morph of the coelomycetous genus Homortomyces was collected for the first time and is described and illustrated.A new family,Homortomycetaceae(Dothideomycetes,families incertae sedis)is introduced to accommodate Homortomyces.Two new genera Neomicrosphaeropsis(Didymellaceae)and Tamaricicola(Pleosporaceae)are introduced in this paper.Phoma tamaricicola was recollected and is placed in Neomicrosphaeropsis based on morphology and molecular data.Ten new species,Cytospora italica,C.unilocularis,Diaporthe ravennica,Eutypella tamaricis,Neomicrosphaeropsis italica,N.novorossica,N.rossica,Keissleriella tamaricicola,Paracamarosporium tamaricis and Tamaricicola muriformis are introduced,while Alternaria tenuissima,Dothiorella sarmentorum,Neofusicoccum luteum,Paraepicoccum amazonense,Pleospora herbarum and Pseudocamarosporium propinquum are reported for the first time on Tamarix spp.with descriptions and illustrations.Multi-gene analyses show that Paraepicoccum amazonense should be placed in Pleosporineae,Pleosporales,where it is closely related to Camarosporium sensu stricto.Several herbarium specimens were studied to illustrate other fungal species recorded on Tamarix species.A comprehensive account of microfungi on Tamarix is provided,which includes a list with data from the literature,as well as those identified in the present study.The taxonomic placement of most taxa discussed in this study is based on a modern taxonomic framework based on analysis of multi-gene sequence data.展开更多
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.31370395 and 31500266)the"One Hundred Talents"project of the Chinese Academy of Sciences(Grant No.29Y127E71)
文摘In the field of phylogenetic analyses, the rbcL gene encoded large subunit Ribulose-1,5-biphosphate carboxylase/oxygenase （Rubisco, EC4.1.1.39）, which plays a crucial role in the process of photosynthesis for most terrestrial plants, has been considered to be conserved; however, recent controversy regarding rbcL conservation has appeared since it was proposed to be under natural selection within all principal lineages of land plants. In this study, by examining the variation of DNA and protein sequences among 17 species in the family Tamaricaceae, three nonsynonymous mutations were identified to be under positive selection. The favored sites were located in the alph-helix domains of Rubisco, with decreased hydrophobicity and increased entropy, which could facilitate C〇 2 penetration into the active site of Rubisco. We also found that the expression level of rbcL in different genotypes of Reaumuria soongarica shifted in response to various stresses such as drought, temperature, salt, and light. This study not only sheds light on the functional/structural features of Rubisco in the evolution scenarios from 〇 3-like into C4 in Tamaricaceae but also provides useful information on directing genetic performance to enhance photosynthesis efficiency of desert plants for sustaining fragile desert ecosystems; fur-thermore, it promotes the ability to cope with desert aridification and global warming.
基金support and providing postgraduate scholarship support to Kasun M.Thambugala.Kevin D.Hyde thanks the Chinese Academy of Sciences(project number 2013T2S0030)the award of Visiting Professorship for Senior International Scientists at Kunming Institute of Botany.The authors extend their sincere appreciations to the Deanship of Scientific Research at King Saud University for its funding this Prolific Research Group(PRG-1436-09)The authors would like to thank the featured microbial resources and diversity investigation in Southwest Karst area(2014FY120100)。
文摘Tamarix species are small trees that grow in various natural habitats and have a wide geographic distribution.Microfungal species previously found on Tamarix and recently collected in Italy and Russia were identified based on morphological characters and analyses of gene sequence data.The sexual morph of the coelomycetous genus Homortomyces was collected for the first time and is described and illustrated.A new family,Homortomycetaceae(Dothideomycetes,families incertae sedis)is introduced to accommodate Homortomyces.Two new genera Neomicrosphaeropsis(Didymellaceae)and Tamaricicola(Pleosporaceae)are introduced in this paper.Phoma tamaricicola was recollected and is placed in Neomicrosphaeropsis based on morphology and molecular data.Ten new species,Cytospora italica,C.unilocularis,Diaporthe ravennica,Eutypella tamaricis,Neomicrosphaeropsis italica,N.novorossica,N.rossica,Keissleriella tamaricicola,Paracamarosporium tamaricis and Tamaricicola muriformis are introduced,while Alternaria tenuissima,Dothiorella sarmentorum,Neofusicoccum luteum,Paraepicoccum amazonense,Pleospora herbarum and Pseudocamarosporium propinquum are reported for the first time on Tamarix spp.with descriptions and illustrations.Multi-gene analyses show that Paraepicoccum amazonense should be placed in Pleosporineae,Pleosporales,where it is closely related to Camarosporium sensu stricto.Several herbarium specimens were studied to illustrate other fungal species recorded on Tamarix species.A comprehensive account of microfungi on Tamarix is provided,which includes a list with data from the literature,as well as those identified in the present study.The taxonomic placement of most taxa discussed in this study is based on a modern taxonomic framework based on analysis of multi-gene sequence data.
