Jasmonic acid(JA)plays important roles in plant resistance to insect herbivores.One important derivative of JA is 12-OH-JA,which is produced by two independent pathways:direct hydroxylation of JA by jasmonate-induced ...Jasmonic acid(JA)plays important roles in plant resistance to insect herbivores.One important derivative of JA is 12-OH-JA,which is produced by two independent pathways:direct hydroxylation of JA by jasmonate-induced oxygenases(JOXs)or hydrolyzation of 12-OH-JA-Ile.Yet the function of 12-OH-JA in plant-herbivore interactions remains largely unknown.In this study,we silenced four JOX homologs independently in the wild tobacco Nicotiana attenuata by virus-induced gene silencing(VIGS),and found that all four JOX homologs are involved in JA hydroxylation.Simultaneously silencing the four JA hydroxylases in VIGS-NaJOXs plants decreased herbivory-induced 12-OH-JA by 33%,but JA and JA-Ile levels increased by 45%and 30%,respectively,compared to those in control plants.Compared to direct hydroxylation from JA,hydrolyzation from 12-OH-JA-Ile is equally important for herbivory-induced 12-OHJA accumulation:in the 12-OH-JA-Ile deficient irJAR4/6 plants,12-OH-JA decreased 34%.Moreover,VIGSNaJOXs plants exhibited enhanced resistance to the generalist herbivore Spodoptera litura.The poor larval performance was strongly correlated with high levels of several JA-Ile-dependent direct defense metabolites in the VIGS-NaJOXs plants.When we simultaneously silenced all four JA hydroxylases in the JAIle-deficient irJAR4/6 background,the enhanced herbivore resistance diminished,demonstrating that enhanced herbivore resistance resulted from elevated JA-Ile levels.Given that silencing these NaJOX-like genes did not detectably alter plant growth but highly increased plant defense levels,we propose that JOX genes are potential targets for genetic improvement of herbivore-resistant crops.展开更多
We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation ...We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation （open lab condition） seeds with MC 23% showed 40% germination. After further drying to MC 21% germination was reduced to 16%. Complete loss in viability resulted when seed moisture was reduced to 18%. The seeds stored at -10℃, 0℃, 10℃ and 28±2℃ （open lab condition） lost their viability within 10 days. Seeds stored in sealed polythene hags and moist sand retained viability for more days than did seeds stored under all other storage conditions. Sensitivity of seeds to lower temperature and desiccation suggest that the storage behavior of K. attenuata seeds is recalcitrant. Seeds stored in moist conditions can, at best, be stored for a period of two months.展开更多
We studied effect of desiccation on Knema attenuata seeds in the laboratory conditions （28 ± 2℃） for 8 days. We also monitored biochemical changes during germination by following standard procedures. Seeds los...We studied effect of desiccation on Knema attenuata seeds in the laboratory conditions （28 ± 2℃） for 8 days. We also monitored biochemical changes during germination by following standard procedures. Seeds lost their viability in 8 days by decreasing to 18% of moisture content from its original value of 31%. The total sugar, protein and lipid contents decreased during seed ageing. An increase was noticed in the protease activity during desiccation. The phenolic content in seed exudates was increased during ageing. The result confirms the degradation of stored biomolecules in seeds during ageing. Desiccation sensitiv- ity and biochemical changes during dehydration confirm its recalcitrant nature.展开更多
On October 1, 2009, sixteen dolphins were obtained from fishermen by incidental catching in the Yellow Sea, China. As the dolphins＇ skin color was ambiguous, morphological parameters were measured, and mitochondrial ...On October 1, 2009, sixteen dolphins were obtained from fishermen by incidental catching in the Yellow Sea, China. As the dolphins＇ skin color was ambiguous, morphological parameters were measured, and mitochondrial DNA cytochrome b （Cyt b） gene sequence was studied to identify the species. Morphological characteristics were consistent with Pantropical spotted dolphins, Stenella attenuata. Furthermore, a partial mitochondrial DNA eytoehrome b （Cyt b） gene sequence as long as 328-bp was studied by extracting genomic DNA from the skins, and six haplotypes were detected in the sixteen dolphins. By comparing homologous sequences available in GenBank （www.ncbi.nlm.nih.gov）, all the six haplotypes had maximal genetic similarity with Pantropical spotted dolphin. Eight species of cetacean （whales and dolphins） are now recognised in the Yellow Sea. To the best of our knowledge, this is the first record of Pantropical spotted dolphins from this region. Despite this species being listed as a Grade II National Key Protected Animal since 1988, little is known of its biology in Chinese waters. We recommend remedial research be undertaken to ensure appropriate management.展开更多
Despite the growing awareness on the importance of gut microbiomes,understanding marine mammal gut microbiomes remains limited due to difficulties in sampling.Spotted dolphins(Stenella attenuata)are widely spread ocea...Despite the growing awareness on the importance of gut microbiomes,understanding marine mammal gut microbiomes remains limited due to difficulties in sampling.Spotted dolphins(Stenella attenuata)are widely spread oceanic cetaceans,and there is a gap in knowledge regarding their gut microbiology.In this study,we opportunistically collected samples from both wild and human-cared spotted dolphins in the southern waters of Hainan Island,China.This provided the opportunity to examine the composition and diversity of the gut microbial communities of this cetacean species.Since these dolphins inhabit a similar water environment,different food sources might be the primary factor distinguishing the gut microbiomes of wild and human-cared populations,offering valuable experimental material to investigate potential differences in gut microbial community structure among marine mammals in similar environments but with varying food sources.We found that the gastrointestinal microbial community structure of wild and human-cared dolphins demonstrated significant differences,both overall and at specific locations.However,no significant difference was observed in the microbial diversity of their gastrointestinal tracts,indicating that the disparities primarily lie in microbiota composition.Additionally,we detected numerous potentially pathogenic bacteria,suggesting a comprehensive future study of marine mammal gut microbiology.Such a study might involve determining health indicator factors associated with these microbiomes.Our study not only supplements information on the gut microbiology of spotted dolphins but also delves into the similarities and differences in gastrointestinal microbial communities within the same marine mammal species when food source variations play a significant role in their lives.展开更多
To defend themselves against herbivore attack, plants produce secondary metabolites, which are variously inducible and constitutively deployed, presumably to optimize their fitness benefits in light of their fitness c...To defend themselves against herbivore attack, plants produce secondary metabolites, which are variously inducible and constitutively deployed, presumably to optimize their fitness benefits in light of their fitness costs. Three phytohormones, jasmonates （JA） and their active forms, the JA-isoleucine （JA-Ile） and ethylene （ET）, are known to play central roles in the elicitation of induced defenses, but little is known about how this mediation changes over ontogeny. The Optimal Defense Theory （ODT） predicts changes in the costs and benefits of the different types of defenses and has been usefully extrapolated to their modes of deployment. Here we studied whether the herbivore-induced accumulation of JA, JA-Ile and ET changed over ontogeny in Nicotiana attenuata, a native tobacco in which inducible defenses are particularly well studied. Herbivore-elicited ET production changed dramatically during six developmental stages, from rosette through flowering, decreasing with the elongation of the first corollas during flower development. This decrease was largely recovered within a day after flower removal by decapitation. A similar pattern was found for the herbivore-induced accumulation of JA and JA-Ile. These results are consistent with ODT predictions and suggest that the last steps in floral development control the inducibility of at least three plant hormones, optimizing defense-growth tradeoffs.展开更多
基金supported by the Key Project of Applied Basic Research Program of Yunnan(2017FA015)the Young Academic and Technical Leader Raising Foundation of Yunnan Province(no. 2017HB063)+1 种基金the Yunnan Academy of Tobacco Agricultural Sciences(2018530000241002 and 2019530000241003)the Biotechnology Experimental Center at the Kunming Institute of Botany,CAS,for supporting plant cultivation.
文摘Jasmonic acid(JA)plays important roles in plant resistance to insect herbivores.One important derivative of JA is 12-OH-JA,which is produced by two independent pathways:direct hydroxylation of JA by jasmonate-induced oxygenases(JOXs)or hydrolyzation of 12-OH-JA-Ile.Yet the function of 12-OH-JA in plant-herbivore interactions remains largely unknown.In this study,we silenced four JOX homologs independently in the wild tobacco Nicotiana attenuata by virus-induced gene silencing(VIGS),and found that all four JOX homologs are involved in JA hydroxylation.Simultaneously silencing the four JA hydroxylases in VIGS-NaJOXs plants decreased herbivory-induced 12-OH-JA by 33%,but JA and JA-Ile levels increased by 45%and 30%,respectively,compared to those in control plants.Compared to direct hydroxylation from JA,hydrolyzation from 12-OH-JA-Ile is equally important for herbivory-induced 12-OHJA accumulation:in the 12-OH-JA-Ile deficient irJAR4/6 plants,12-OH-JA decreased 34%.Moreover,VIGSNaJOXs plants exhibited enhanced resistance to the generalist herbivore Spodoptera litura.The poor larval performance was strongly correlated with high levels of several JA-Ile-dependent direct defense metabolites in the VIGS-NaJOXs plants.When we simultaneously silenced all four JA hydroxylases in the JAIle-deficient irJAR4/6 background,the enhanced herbivore resistance diminished,demonstrating that enhanced herbivore resistance resulted from elevated JA-Ile levels.Given that silencing these NaJOX-like genes did not detectably alter plant growth but highly increased plant defense levels,we propose that JOX genes are potential targets for genetic improvement of herbivore-resistant crops.
文摘We performed desiccation and storage trials to better understand storage behavior of Knema attenuata seeds. Mature seeds with moisture content （MC） of 31% exhibited 73% germination. During the period of desiccation （open lab condition） seeds with MC 23% showed 40% germination. After further drying to MC 21% germination was reduced to 16%. Complete loss in viability resulted when seed moisture was reduced to 18%. The seeds stored at -10℃, 0℃, 10℃ and 28±2℃ （open lab condition） lost their viability within 10 days. Seeds stored in sealed polythene hags and moist sand retained viability for more days than did seeds stored under all other storage conditions. Sensitivity of seeds to lower temperature and desiccation suggest that the storage behavior of K. attenuata seeds is recalcitrant. Seeds stored in moist conditions can, at best, be stored for a period of two months.
文摘We studied effect of desiccation on Knema attenuata seeds in the laboratory conditions （28 ± 2℃） for 8 days. We also monitored biochemical changes during germination by following standard procedures. Seeds lost their viability in 8 days by decreasing to 18% of moisture content from its original value of 31%. The total sugar, protein and lipid contents decreased during seed ageing. An increase was noticed in the protease activity during desiccation. The phenolic content in seed exudates was increased during ageing. The result confirms the degradation of stored biomolecules in seeds during ageing. Desiccation sensitiv- ity and biochemical changes during dehydration confirm its recalcitrant nature.
基金Supported by the International Cooperation Department,State Oceanic Administration(No.HC10701-10(1))the National Special Research Fund for Non-Profit Marine Sector(No.201105011)+1 种基金the National Natural Science Foundation of China(No.41206159)the Natural Science Foundation of Shandong Province,China(No.Y2007D75)
文摘On October 1, 2009, sixteen dolphins were obtained from fishermen by incidental catching in the Yellow Sea, China. As the dolphins＇ skin color was ambiguous, morphological parameters were measured, and mitochondrial DNA cytochrome b （Cyt b） gene sequence was studied to identify the species. Morphological characteristics were consistent with Pantropical spotted dolphins, Stenella attenuata. Furthermore, a partial mitochondrial DNA eytoehrome b （Cyt b） gene sequence as long as 328-bp was studied by extracting genomic DNA from the skins, and six haplotypes were detected in the sixteen dolphins. By comparing homologous sequences available in GenBank （www.ncbi.nlm.nih.gov）, all the six haplotypes had maximal genetic similarity with Pantropical spotted dolphin. Eight species of cetacean （whales and dolphins） are now recognised in the Yellow Sea. To the best of our knowledge, this is the first record of Pantropical spotted dolphins from this region. Despite this species being listed as a Grade II National Key Protected Animal since 1988, little is known of its biology in Chinese waters. We recommend remedial research be undertaken to ensure appropriate management.
基金National Natural Science Foundation of China(Grant Nos.39899400 and 30499340)the Knowledge Innovation Project of Chinese Academy of Sciences(Grant No.KSCX-SW-122)
基金funded by the Hainan Provincial Natural Science Foundation of China(422RC744)Youth Innovation Promotion Association of Chinese Academy of Sciences(2020363)the“One Belt and One Road”Science and Technology Cooperation Special Program of the International Partnership Program of the Chinese Academy of Sciences(Grant No.183446KYSB20200016).
文摘Despite the growing awareness on the importance of gut microbiomes,understanding marine mammal gut microbiomes remains limited due to difficulties in sampling.Spotted dolphins(Stenella attenuata)are widely spread oceanic cetaceans,and there is a gap in knowledge regarding their gut microbiology.In this study,we opportunistically collected samples from both wild and human-cared spotted dolphins in the southern waters of Hainan Island,China.This provided the opportunity to examine the composition and diversity of the gut microbial communities of this cetacean species.Since these dolphins inhabit a similar water environment,different food sources might be the primary factor distinguishing the gut microbiomes of wild and human-cared populations,offering valuable experimental material to investigate potential differences in gut microbial community structure among marine mammals in similar environments but with varying food sources.We found that the gastrointestinal microbial community structure of wild and human-cared dolphins demonstrated significant differences,both overall and at specific locations.However,no significant difference was observed in the microbial diversity of their gastrointestinal tracts,indicating that the disparities primarily lie in microbiota composition.Additionally,we detected numerous potentially pathogenic bacteria,suggesting a comprehensive future study of marine mammal gut microbiology.Such a study might involve determining health indicator factors associated with these microbiomes.Our study not only supplements information on the gut microbiology of spotted dolphins but also delves into the similarities and differences in gastrointestinal microbial communities within the same marine mammal species when food source variations play a significant role in their lives.
文摘To defend themselves against herbivore attack, plants produce secondary metabolites, which are variously inducible and constitutively deployed, presumably to optimize their fitness benefits in light of their fitness costs. Three phytohormones, jasmonates （JA） and their active forms, the JA-isoleucine （JA-Ile） and ethylene （ET）, are known to play central roles in the elicitation of induced defenses, but little is known about how this mediation changes over ontogeny. The Optimal Defense Theory （ODT） predicts changes in the costs and benefits of the different types of defenses and has been usefully extrapolated to their modes of deployment. Here we studied whether the herbivore-induced accumulation of JA, JA-Ile and ET changed over ontogeny in Nicotiana attenuata, a native tobacco in which inducible defenses are particularly well studied. Herbivore-elicited ET production changed dramatically during six developmental stages, from rosette through flowering, decreasing with the elongation of the first corollas during flower development. This decrease was largely recovered within a day after flower removal by decapitation. A similar pattern was found for the herbivore-induced accumulation of JA and JA-Ile. These results are consistent with ODT predictions and suggest that the last steps in floral development control the inducibility of at least three plant hormones, optimizing defense-growth tradeoffs.
