Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological infor...Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological information associated with environmental changes as it reflects their growth potential.To evaluate the effects of the changes in salinity and nutrients,the photosynthetic efficiency of a green macroalga Ulva fasciata from the Daya Bay was tested at a range of salinity(i.e.,31 to 10 psu)and nitrogen content(i.e.,5 to 60μmol L^(-1)).The results showed that cellular chlorophyll a(Chl a),carbohydrate and protein contents of U.fasciata were increased due to reduced salinity,and were decreased by interactive nitrogen enrichment.Within a short culture period(i.e.,18 h),the reduced salinity decreased the maximum photosynthetic efficiency(rETRmax and Pmax)derived from the rapid light response curve and photosynthetic oxygen evolution rate versus irradiance curve,respectively,as well as the saturation irradiance(E_(K)).This reducing effect diminished with enlonged cultivation time and reversed to a stimulating effect after 24 h of cultivation.The nitrogen enrichment stimulated the rETRmax and Pmax,as well as the E_(K),regardless of salinity,especially within short-term cultivation period(i.e.,<24 h).In addition,our results indicate that seawater freshening lowers the photosynthetic efficiency of U.fasciata in the short term,which is mitigated by nitrogen enrichment,but stimulates it in the long term,providing insight into how macroalgae thrive in coastal or estuarine waters where salinity and nutrients normally covary strongly.展开更多
Since 2007,the world's largest transregional green tides caused by Ulva prolifera have periodically occurred in China.The morphology of U.prolifera drastically changes during the drifting period,but the reason for...Since 2007,the world's largest transregional green tides caused by Ulva prolifera have periodically occurred in China.The morphology of U.prolifera drastically changes during the drifting period,but the reason for this phenomenon has still been under debate.Our results showed that temperature partly explained the changes in the morphology of U.prolifera,with a determining factor of 0.498.The ratio of highly branched thalli decreased as the temperature increased from around 25 to 30℃.Because morphological changes and physiological acclimation synergistically occurred in floating macroalgae,we hypothesized that if the morphology of U.prolifera is also determined by its development state,and the U.prolifea thalli with different development states should have distinct morphological and physiological traits even under the same environmental conditions.To test the hypothesis,we investigated the photosynthesis of U.prolifera and found a higher photosynthetic capacity but lower photoprotective capacity in algae that grew in the branched development state compared to those in the unbranched development state.Combined with other field observations and lab experiments,we suggest that both temperature and development state contribute to the morphological changes of U.prolifera.Given the varying trends of temperature during U.prolifera blooms in past eleven years and the initial occurrence of U.prolifera thalli in the branched development state in the source of algal bloom,we emphasize the need for source management of green tides.展开更多
The large-scale green tide(YSGT)has been persisting in the Yellow Sea over a decade,while its impacts on various trophic organisms remained inconclusive.Field surveys were conducted to investigate the dynamic of plank...The large-scale green tide(YSGT)has been persisting in the Yellow Sea over a decade,while its impacts on various trophic organisms remained inconclusive.Field surveys were conducted to investigate the dynamic of planktonic crustacean community in response to the massive blooming of Ulva biomass in the Subei Shoal and the adjacent water.A rapid change of the planktonic crustacean populations during the development process of YSGT was revealed by this study.Copepods,mysids and euphausiids,and amphipods were three major groups of the planktonic crustacean community in the survey region.Copepods were the dominant group,accounting for 82.16%±3.41%of the total biomass.The total biomass of planktonic crustaceans decreased from 70.98 mg/m3to 7.36 mg/m3with the bloom of Ulva algae.Copepods,mysids and euphausiids were the two groups contributing for the rapid decline.At the same time,amphipods showed evident species succession.The planktonic Themisto gaudichaudii absolutely dominated before the green tide,while the epizootic Sunamphitoe tea and Apohyale sp.succeeded during the bloom.Based on this study,the massive YSGTs seriously destructed the planktonic crustacean community and reduced the secondary productivity,which likely impaired the fishery resources and benthos through trophic chains.展开更多
Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research...Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research on the regulation of high salt stress in this species.In this study,we observed that high salt stress suppressed the growth of U.prolifera and leading to the nitric oxide(NO)accumulation,along with increased gene expression levels and enzyme activity of S-nitrosoglutathione reductase(GSNOR).Treatment with GSNOR inhibitor resulted in elevated NO levels under high salt stress,accompanied by reduced activity of antioxidant enzymes and decreased glutathione(GSH)accumulation,making U.prolifera more sensitive to high salt stress.Conversely,NO scavenger treatment not only reduced NO levels,but also weakened the high salt stress tolerance of U.prolifera.Furthermore,using tandem mass tags(TMT)switch analysis and mass spectrometry,we observed a significant increase in S nitrosylated protein levels in U.prolifera under high salt stress,with further augmentation upon GSNOR inhibitor treatment.We also found high salt stress induced S-nitrosylation(SNO)of glutathione reductase(GR),which is negatively regulated by GSNOR,resulting in increased GR activity.Our results show that under short-term high salt stress,the elevated expression level of GSNOR avoided excessive accumulation of NO,and a certain amount of NO enhanced the activity of antioxidant enzymes through SNO modification,which improve the high salt stress tolerance of U.prolifera,whereas under long-term high salt stress,excessive NO was toxic to U.prolifera.展开更多
Ulva prolifera green tides are becoming aworldwide environmental problem,especially in the Yellow Sea,China.However,the effects of the occurrence of U.prolifera green tides on the community organization and stability ...Ulva prolifera green tides are becoming aworldwide environmental problem,especially in the Yellow Sea,China.However,the effects of the occurrence of U.prolifera green tides on the community organization and stability of surrounding microbiomes have still not been de-termined.Here,the prokaryotic microbial community network stability and assembly char-acteristics were systematically analyzed and compared between the green tide and non-green tide periods.U.prolifera blooms weaken the community complexity and robustness of surrounding microbiomes,increasing fragmentation and decreasing diversity.Bacteria and archaea exhibited distinct community distributions and assembly patterns under the influ-ence of green tides,and bacterial communities were more sensitive to outbreaks of green tides.The bacterial communities exhibited a greater niche breadth and a lower phyloge-netic distance during the occurrence of U.prolifera green tides compared to those during the non-green tide period while archaeal communities remained unchanged,suggesting that the bacterial communities underwent stronger homogeneous selection and more sensitive to green tide blooms than the archaeal communities.Piecewise structural equation model analysis revealed that the different responses of major prokaryotic microbial groups,such as Cyanobacteria,to environmental variables during green tides,were influenced by the variations in pH and nitrate during green tides and correlated with the salinity gradient during the non-green tide period.This study elucidates the response of the adaptability,associations,and stability of surrounding microbiomes to outbreaks of U.prolifera green tides.展开更多
Dissolved organic carbon(DOC)and particulate organic carbon(POC)play essential roles in the carbon sequestration,with macroalgae being major producers of DOC and POC.The intertidal zone is the transition area between ...Dissolved organic carbon(DOC)and particulate organic carbon(POC)play essential roles in the carbon sequestration,with macroalgae being major producers of DOC and POC.The intertidal zone is the transition area between the ocean and the land,the main habitat of macroalgae.However,few studies have focused on the regulation of tidally induced desiccation-rewetting cycles on carbon sequestration by intertidal macroalgae.Therefore,we simulated the intertidal environments to investigate the effects of desiccation-rewetting cycles on the growth,DOC and POC release mechanisms of Ulva pertusa.After 14 days of experiments,the DOC release capacities of U.pertusa(per gram fresh weight)were 1.08,5.31,9.74 and 7.47 mg/g in the subtidal,low,middle and high tide zones,respectively.The corresponding POC release capacities were 0.04,1.00,3.90 and 1.38 mg/g.Combined biological carbon sequestration,the total carbon sequestration capacities of U.pertusa in the subtidal,low,middle and high tide zones were 24.73,32.84,27.83 and 16.97 mg/g,respectively.The results indicated that the highest carbon sequestration capacity of U.pertusa occurred in low tide zones.In conclusion,the results will provide support for the application of seaweed negative emissions.展开更多
Ulvan, rhamnan sulfate, was extracted from the edible green seaweed, Ana-aosa (Ulva pertusa), which is grown on the coast of the Okinawa Islands. The yield of ulvan was 8.5% (W/W), and the total carbohydrates, uronic ...Ulvan, rhamnan sulfate, was extracted from the edible green seaweed, Ana-aosa (Ulva pertusa), which is grown on the coast of the Okinawa Islands. The yield of ulvan was 8.5% (W/W), and the total carbohydrates, uronic acid and sulfuric acid and ash contents were 67.3%, 23.8%, 19.7% and 22.6%, respectively. L-Rhamnose, D-xylose and D-glucose residues were identified by liquid chromatography, and their molar ratio was 4.0:0.1:0.3. D-Glucuronic and L-idulonic acid residues were also identified in molar ratio of 1.0:0.2. The NMR (13C and 1H) and methylation analysis revealed terminal β-D-glucruonic acid, terminal α-L-idulonic acid, 1,3-linked α-L-rhamnose, 1,4-linked α-L-rhamnose, 1,2,4-linked α-L-rhamnose, 1,3,4-linked α-L-rhamnose, 1,2,3,4-linked α-L-rhamnose and 1,3,4-linked β-D-xylose. The sulfate groups were attached at the C-2 and C-3 positions of the 1,4-linked α-L-rhamnose as well as C-3 of the 1,4-linked β-D-xylose residues. The chemical structure of the ulvan from Ulva pertusa was determined.展开更多
Intertidal macroalgae experience continual alternation of photosynthesis between aquatic state at high tide and aerial state at low tide. The comparative photosynthetic responses to inorganic carbon were investigated...Intertidal macroalgae experience continual alternation of photosynthesis between aquatic state at high tide and aerial state at low tide. The comparative photosynthetic responses to inorganic carbon were investigated in the common intertidal macroalga Ulva lactuca L. along the coast of Shantou between aquatic and aerial state. The inorganic carbon dissolved in seawater at present could fully (at 10 ℃ or 20 ℃) or nearly (at 30 ℃) saturate the aquatic photosynthesis of U. lactuca . However, the aerial photosynthesis was limited by current ambient atmospheric CO 2 level, and such a limitation was more severe at higher temperature (20-30 ℃) than at lower temperature (10 ℃). The carbon_saturated maximal photosynthesis of U. lactuca under aerial state was much greater than that under aquatic state at 10 ℃ and 20 ℃, while the maximal photosynthesis under both states was similar at 30 ℃. The aerial values of K m (CO 2) for photosynthesis were higher than the aquatic values. On the contrary, the values of apparent photosynthetic CO 2 conductance under aerial state were considerably lower than that under aquatic state. It was concluded that the increase of atmospheric CO 2 would enhance the primary productivity of U. lactuca through stimulating the photosynthesis under aerial state during low tide.展开更多
The green seaweeds Ulva linza and U.prolifera are closely related species.They usually co-occur widely and have important ecological significance as primary producers thriving in the intertidal zone.In the Yellow Sea,...The green seaweeds Ulva linza and U.prolifera are closely related species.They usually co-occur widely and have important ecological significance as primary producers thriving in the intertidal zone.In the Yellow Sea,a genetically unique floating ecotype of U.prolifera even bloomed to cause serious green tides.However,there is still a lack of appropriate molecular markers to distinguish these two species,partially due to limited evaluations on the intraspecific variations in U.prolifera among dif ferent ecotypes.Since organelle genomes could provide rich genetic resources for phylogenetic analysis and development of genetic markers,in this study,the chloroplast genome from one attached population of U.prolifera was completely sequenced,and comparative genomic analyses were performed with other existing chloroplast genomes from U.linza and the floating ecotype of U.prolifera.The results showed that in spite of the high level of collinearity among three genomes,there were plenty of genetic variations especially within the non-coding regions,including introns and gene spacer regions.A strategy was proposed that only those signals of variation,which were identical between two ecotypes of U.prolifera but divergent between U.linza and U.prolifera,were selected to develop the interspecific markers for U.linza and U.prolifera.Two candidate markers,psa B and pet B,were shown to be able to distinguish these two closely related species and were applicable to more attached populations of U.prolifera from a wide range of geographical sources.In addition to the interspecific marker,this study would also provide resources for the development of intraspecific markers for U.prolifera.These markers might contribute to the surveys for Ulva species composition and green tide monitoring especially in the Yellow Sea region.展开更多
基金funded by the National Key Research and Development Program of China(No.20022YFC3102405)the National Natural Science Foundation of China(Nos.42425004,32371665)the Natural Science Foundation of Guangdong Province(Nos.2022A1515011461,2022A1515011831)。
文摘Macroalgae dominate nutrient dynamics and function as high-value foods for microbial,meio-and macrofaunal communities in coastal ecosystems.Because of this vital role,it is important to clarify the physiological information associated with environmental changes as it reflects their growth potential.To evaluate the effects of the changes in salinity and nutrients,the photosynthetic efficiency of a green macroalga Ulva fasciata from the Daya Bay was tested at a range of salinity(i.e.,31 to 10 psu)and nitrogen content(i.e.,5 to 60μmol L^(-1)).The results showed that cellular chlorophyll a(Chl a),carbohydrate and protein contents of U.fasciata were increased due to reduced salinity,and were decreased by interactive nitrogen enrichment.Within a short culture period(i.e.,18 h),the reduced salinity decreased the maximum photosynthetic efficiency(rETRmax and Pmax)derived from the rapid light response curve and photosynthetic oxygen evolution rate versus irradiance curve,respectively,as well as the saturation irradiance(E_(K)).This reducing effect diminished with enlonged cultivation time and reversed to a stimulating effect after 24 h of cultivation.The nitrogen enrichment stimulated the rETRmax and Pmax,as well as the E_(K),regardless of salinity,especially within short-term cultivation period(i.e.,<24 h).In addition,our results indicate that seawater freshening lowers the photosynthetic efficiency of U.fasciata in the short term,which is mitigated by nitrogen enrichment,but stimulates it in the long term,providing insight into how macroalgae thrive in coastal or estuarine waters where salinity and nutrients normally covary strongly.
基金supported by the National Key Research and Development Program of China(No.2022YFC3106000)the major innovation project for the science education industry integration pilot project of Qilu University of Technology(Shandong Academy of Sciences)(No.2023JBZ03)+1 种基金the talent research projects of Qilu University of Technology(Shandong Academy of Science)(No.2023RCKY039)the open funding project of Key Laboratory of Marine ecological monitoring and restoration technologies,MNR,China(No.MEMRT202301)。
文摘Since 2007,the world's largest transregional green tides caused by Ulva prolifera have periodically occurred in China.The morphology of U.prolifera drastically changes during the drifting period,but the reason for this phenomenon has still been under debate.Our results showed that temperature partly explained the changes in the morphology of U.prolifera,with a determining factor of 0.498.The ratio of highly branched thalli decreased as the temperature increased from around 25 to 30℃.Because morphological changes and physiological acclimation synergistically occurred in floating macroalgae,we hypothesized that if the morphology of U.prolifera is also determined by its development state,and the U.prolifea thalli with different development states should have distinct morphological and physiological traits even under the same environmental conditions.To test the hypothesis,we investigated the photosynthesis of U.prolifera and found a higher photosynthetic capacity but lower photoprotective capacity in algae that grew in the branched development state compared to those in the unbranched development state.Combined with other field observations and lab experiments,we suggest that both temperature and development state contribute to the morphological changes of U.prolifera.Given the varying trends of temperature during U.prolifera blooms in past eleven years and the initial occurrence of U.prolifera thalli in the branched development state in the source of algal bloom,we emphasize the need for source management of green tides.
基金the National Natural Science Foundation of China(No.42276221)the Marine S&T Fund of Shandong Province for Laoshan Laboratory(No.LSK202203700)+1 种基金the National Key Research and Development Program of China(No.2022YFC3106000)the Taishan Scholars Program(No.tstp20230624)。
文摘The large-scale green tide(YSGT)has been persisting in the Yellow Sea over a decade,while its impacts on various trophic organisms remained inconclusive.Field surveys were conducted to investigate the dynamic of planktonic crustacean community in response to the massive blooming of Ulva biomass in the Subei Shoal and the adjacent water.A rapid change of the planktonic crustacean populations during the development process of YSGT was revealed by this study.Copepods,mysids and euphausiids,and amphipods were three major groups of the planktonic crustacean community in the survey region.Copepods were the dominant group,accounting for 82.16%±3.41%of the total biomass.The total biomass of planktonic crustaceans decreased from 70.98 mg/m3to 7.36 mg/m3with the bloom of Ulva algae.Copepods,mysids and euphausiids were the two groups contributing for the rapid decline.At the same time,amphipods showed evident species succession.The planktonic Themisto gaudichaudii absolutely dominated before the green tide,while the epizootic Sunamphitoe tea and Apohyale sp.succeeded during the bloom.Based on this study,the massive YSGTs seriously destructed the planktonic crustacean community and reduced the secondary productivity,which likely impaired the fishery resources and benthos through trophic chains.
基金Supported by the National Natural Science Foundation of China(No.42276100)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research on the regulation of high salt stress in this species.In this study,we observed that high salt stress suppressed the growth of U.prolifera and leading to the nitric oxide(NO)accumulation,along with increased gene expression levels and enzyme activity of S-nitrosoglutathione reductase(GSNOR).Treatment with GSNOR inhibitor resulted in elevated NO levels under high salt stress,accompanied by reduced activity of antioxidant enzymes and decreased glutathione(GSH)accumulation,making U.prolifera more sensitive to high salt stress.Conversely,NO scavenger treatment not only reduced NO levels,but also weakened the high salt stress tolerance of U.prolifera.Furthermore,using tandem mass tags(TMT)switch analysis and mass spectrometry,we observed a significant increase in S nitrosylated protein levels in U.prolifera under high salt stress,with further augmentation upon GSNOR inhibitor treatment.We also found high salt stress induced S-nitrosylation(SNO)of glutathione reductase(GR),which is negatively regulated by GSNOR,resulting in increased GR activity.Our results show that under short-term high salt stress,the elevated expression level of GSNOR avoided excessive accumulation of NO,and a certain amount of NO enhanced the activity of antioxidant enzymes through SNO modification,which improve the high salt stress tolerance of U.prolifera,whereas under long-term high salt stress,excessive NO was toxic to U.prolifera.
基金supported by the National Key Research and Development Program of China(No.2022YFC2807500)Laoshan Laboratory(No.LSKJ202203201)+1 种基金the National Natural Science Foundation of China(Nos.42206147,42120104006 and 42176111)the Natural Science Foundation of Shandong Province(Nos.ZR2022QD046,ZR2021QD051).
文摘Ulva prolifera green tides are becoming aworldwide environmental problem,especially in the Yellow Sea,China.However,the effects of the occurrence of U.prolifera green tides on the community organization and stability of surrounding microbiomes have still not been de-termined.Here,the prokaryotic microbial community network stability and assembly char-acteristics were systematically analyzed and compared between the green tide and non-green tide periods.U.prolifera blooms weaken the community complexity and robustness of surrounding microbiomes,increasing fragmentation and decreasing diversity.Bacteria and archaea exhibited distinct community distributions and assembly patterns under the influ-ence of green tides,and bacterial communities were more sensitive to outbreaks of green tides.The bacterial communities exhibited a greater niche breadth and a lower phyloge-netic distance during the occurrence of U.prolifera green tides compared to those during the non-green tide period while archaeal communities remained unchanged,suggesting that the bacterial communities underwent stronger homogeneous selection and more sensitive to green tide blooms than the archaeal communities.Piecewise structural equation model analysis revealed that the different responses of major prokaryotic microbial groups,such as Cyanobacteria,to environmental variables during green tides,were influenced by the variations in pH and nitrate during green tides and correlated with the salinity gradient during the non-green tide period.This study elucidates the response of the adaptability,associations,and stability of surrounding microbiomes to outbreaks of U.prolifera green tides.
基金the National Key Research and Development Program of China(No.2022YFC 3106001)the National Natural Science Foundation of China(No.42206131)+2 种基金the Projects of Science&Technology Plan in Yantai City(No.2023ZDCX039)the Ocean Negative Carbon Emissions(ONCE)Programthe Key Technology Research and Application of Ecological and Efficient Comprehensive Utilization in‘Fishery-Photovoltaic Integration’Seawater Ponds in the Yellow River Delta(No.DYYG2024-10)。
文摘Dissolved organic carbon(DOC)and particulate organic carbon(POC)play essential roles in the carbon sequestration,with macroalgae being major producers of DOC and POC.The intertidal zone is the transition area between the ocean and the land,the main habitat of macroalgae.However,few studies have focused on the regulation of tidally induced desiccation-rewetting cycles on carbon sequestration by intertidal macroalgae.Therefore,we simulated the intertidal environments to investigate the effects of desiccation-rewetting cycles on the growth,DOC and POC release mechanisms of Ulva pertusa.After 14 days of experiments,the DOC release capacities of U.pertusa(per gram fresh weight)were 1.08,5.31,9.74 and 7.47 mg/g in the subtidal,low,middle and high tide zones,respectively.The corresponding POC release capacities were 0.04,1.00,3.90 and 1.38 mg/g.Combined biological carbon sequestration,the total carbon sequestration capacities of U.pertusa in the subtidal,low,middle and high tide zones were 24.73,32.84,27.83 and 16.97 mg/g,respectively.The results indicated that the highest carbon sequestration capacity of U.pertusa occurred in low tide zones.In conclusion,the results will provide support for the application of seaweed negative emissions.
文摘Ulvan, rhamnan sulfate, was extracted from the edible green seaweed, Ana-aosa (Ulva pertusa), which is grown on the coast of the Okinawa Islands. The yield of ulvan was 8.5% (W/W), and the total carbohydrates, uronic acid and sulfuric acid and ash contents were 67.3%, 23.8%, 19.7% and 22.6%, respectively. L-Rhamnose, D-xylose and D-glucose residues were identified by liquid chromatography, and their molar ratio was 4.0:0.1:0.3. D-Glucuronic and L-idulonic acid residues were also identified in molar ratio of 1.0:0.2. The NMR (13C and 1H) and methylation analysis revealed terminal β-D-glucruonic acid, terminal α-L-idulonic acid, 1,3-linked α-L-rhamnose, 1,4-linked α-L-rhamnose, 1,2,4-linked α-L-rhamnose, 1,3,4-linked α-L-rhamnose, 1,2,3,4-linked α-L-rhamnose and 1,3,4-linked β-D-xylose. The sulfate groups were attached at the C-2 and C-3 positions of the 1,4-linked α-L-rhamnose as well as C-3 of the 1,4-linked β-D-xylose residues. The chemical structure of the ulvan from Ulva pertusa was determined.
文摘Intertidal macroalgae experience continual alternation of photosynthesis between aquatic state at high tide and aerial state at low tide. The comparative photosynthetic responses to inorganic carbon were investigated in the common intertidal macroalga Ulva lactuca L. along the coast of Shantou between aquatic and aerial state. The inorganic carbon dissolved in seawater at present could fully (at 10 ℃ or 20 ℃) or nearly (at 30 ℃) saturate the aquatic photosynthesis of U. lactuca . However, the aerial photosynthesis was limited by current ambient atmospheric CO 2 level, and such a limitation was more severe at higher temperature (20-30 ℃) than at lower temperature (10 ℃). The carbon_saturated maximal photosynthesis of U. lactuca under aerial state was much greater than that under aquatic state at 10 ℃ and 20 ℃, while the maximal photosynthesis under both states was similar at 30 ℃. The aerial values of K m (CO 2) for photosynthesis were higher than the aquatic values. On the contrary, the values of apparent photosynthetic CO 2 conductance under aerial state were considerably lower than that under aquatic state. It was concluded that the increase of atmospheric CO 2 would enhance the primary productivity of U. lactuca through stimulating the photosynthesis under aerial state during low tide.
基金Supported by the Science&Technology Basic Resources Investigation Program of China(No.2018FY100205)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23050302)+2 种基金the National Key R&D Program of China(No.2018YFD0901500)the National Natural Science Foundation of China(No.41776153)the Key R&D Program of Shandong Province(No.2019GSF107012)。
文摘The green seaweeds Ulva linza and U.prolifera are closely related species.They usually co-occur widely and have important ecological significance as primary producers thriving in the intertidal zone.In the Yellow Sea,a genetically unique floating ecotype of U.prolifera even bloomed to cause serious green tides.However,there is still a lack of appropriate molecular markers to distinguish these two species,partially due to limited evaluations on the intraspecific variations in U.prolifera among dif ferent ecotypes.Since organelle genomes could provide rich genetic resources for phylogenetic analysis and development of genetic markers,in this study,the chloroplast genome from one attached population of U.prolifera was completely sequenced,and comparative genomic analyses were performed with other existing chloroplast genomes from U.linza and the floating ecotype of U.prolifera.The results showed that in spite of the high level of collinearity among three genomes,there were plenty of genetic variations especially within the non-coding regions,including introns and gene spacer regions.A strategy was proposed that only those signals of variation,which were identical between two ecotypes of U.prolifera but divergent between U.linza and U.prolifera,were selected to develop the interspecific markers for U.linza and U.prolifera.Two candidate markers,psa B and pet B,were shown to be able to distinguish these two closely related species and were applicable to more attached populations of U.prolifera from a wide range of geographical sources.In addition to the interspecific marker,this study would also provide resources for the development of intraspecific markers for U.prolifera.These markers might contribute to the surveys for Ulva species composition and green tide monitoring especially in the Yellow Sea region.
