The existence of multigenic families in the mevalonate pathway suggests divergent functional roles for pathway components involved in the biosynthesis of plant sterols. Squalene epoxidases （SQEs） are key components ...The existence of multigenic families in the mevalonate pathway suggests divergent functional roles for pathway components involved in the biosynthesis of plant sterols. Squalene epoxidases （SQEs） are key components of this pathway, and Squalene Epoxidase 1 （SQE1） has been identified as a fundamental enzyme in this biosynthetic step. In the present work, we extended the characterization of the remaining SQE family members, phylogenetically resolving between true SQEs and a subfamily of SQE-like proteins that is exclusive to Brassicaceae. Functional characterization of true SQE family members, Squalene Epox- idase 2 （SQE2） and Squalene Epoxidase 3 （SQE3）, indicates that SQE3, but not SQE2, contributes to the bulk SQE activity in Arabidopsis, with sqe3-1 mutants accumulating squalene and displaying sensitivity to ter- binafine. We genetically demonstrated that SQE3 seems to play a particularly significant role in embryo development. Also, SQE1 and SQE3 both localize in the endoplasmic reticulum, and SQE3 can functionally complement SQEI. Thus, SQE1 and SQE3 seem to be two functionally unequal redundant genes in the pro- motion of plant SQE activity in Arabidopsis.展开更多
Trincadeira and Aragonez are two important grapevine cultivars in the Iberian Peninsula, used for high quality red wines production. Both cultivars are strongly affected by fungal diseases, with consequent high loses ...Trincadeira and Aragonez are two important grapevine cultivars in the Iberian Peninsula, used for high quality red wines production. Both cultivars are strongly affected by fungal diseases, with consequent high loses on plant productivity and fruit quality. A successful protocol for plant regeneration via somatic embryogenesis (SE) was established for both cultivars allowing further plant improvement based on gene transfer technology. Several factors were evaluated during the three different phases which characterize an SE plant regeneration protocol. The culture room temperature during the induction phase, a parameter usually accepted as standard by most researchers, proved in these trials to significantly affect the embryo induction rates. Concerning embryo conversion, it was specially affected by the embryo developmental stage, by the intensity and duration of the chilling treatment and by the supplementation of conversion culture medium with activated charcoal. The responses obtained, both for induction and conversion, proved to be highly genotype dependent. Calli structure, as well as embryo integrity, was histologically observed, allowing to characterize embryonic and non-embryonic masses and to identify abnormalities on embryo development.展开更多
The value of crop wild relatives has long been acknowledged and this wild resource has been used to improve crop performance with clear economic benefits. Sugar beet (Beta vulgaris subsp. vulgaris) is the most economi...The value of crop wild relatives has long been acknowledged and this wild resource has been used to improve crop performance with clear economic benefits. Sugar beet (Beta vulgaris subsp. vulgaris) is the most economically valuable crop species in the order Caryophyllales, B. vulgaris subsp. maritima being the ancestor of the cultivated beets. The wild species of the genus Beta s.l. are commonly found in coastal areas of Europe and Mediterranean Region, where a rich genetic heritage still exists. Broadening the genetic base of sugar beet by introgression with wild relatives is a growing need regarding the maintenance of ecologically important traits. Since wild relatives have adapted to specific habitats, they constitute an important source of novel traits for the beet breeding pool. So, we conducted a broader research project aiming to delimit taxa and identify priority locations to establish genetic reserves of the wild Beta species occurring in Portugal (Western Iberian Peninsula). The aim of this study was: 1) to identify and characterize the main habitats of these wild Beta species;and 2) to present a review of some genetic tools available for future application in sugar beet breeding. In this review, we have focused on EcoTILLING as a molecular tool to assess DNA polymerphisms in wild populations of Beta and identify candidate genes related to drought and salt tolerance, as well as addressed some issues related to next-generation sequencing (NGS) technologies as a new molecular tool to assess adaptive genetic variation on the wild relatives of sugar beet.展开更多
Listeria monocytogenes is a foodborne pathogen capable of surviving under challenging conditions both outside and inside the host. During the transition from exponential to stationary phase it experiences a series of ...Listeria monocytogenes is a foodborne pathogen capable of surviving under challenging conditions both outside and inside the host. During the transition from exponential to stationary phase it experiences a series of environmental changes that require an appropriate response to maintain cell viability. In this study the autolytic behaviour of a L. monocytogenes strain was investigated by two-dimensional electrophoresis. The study was done at the permissive autolysis temperature, 30℃ and at 20℃, an autolysis non-permissive temperature. An autolytic strain proteome was also compared to a non-autolytic strain at the permissive autolysis temperature. The autolytic strain proteome at 30℃ in comparison to 20℃ evidenced increased synthesis of the P60 autolysin, glycolytic enzymes and proteins related with environmental stress responses. The over-production of P45 autolysin, was observed when the autolytic strain proteome was compared with the non-autolytic strain. The proteomes at the non-permissive temperature and the proteome of the non-autolytic strain were characterized by a diminished synthesis of several stress related proteins. The lack of autolysis seems to be associated to the over-production of proteins linked to fatty acid and amino acid synthesis, transcription regulation and cell morphogenesis as evidenced by the proteome at the non-permissive temperature and the non-autolytic strain. Autolysis proteome evidenced the over-production of P60 autolysins, glycolysis and stress proteins whereas the proteome obtained in conditions of absence of autolysis reveal a completely different group of proteins. Possible targets to activate listerial autolysis were identified.展开更多
The sub-Saharan region holds a wide variety of indigenous plant species, still offering the possibility to discover very interesting new natural products with potential therapeutic value. Most of the African populatio...The sub-Saharan region holds a wide variety of indigenous plant species, still offering the possibility to discover very interesting new natural products with potential therapeutic value. Most of the African population depends on traditional medicine for primary health care, however, neurological disorders are often not considered as common diseases and many people with mental illnesses, like epilepsy, are severely affected by health-related stigma and discrimination. Epilepsy is the most common serious chronic brain disorder, estimated to affect at least 10 million people in Africa. Guinea-Bissau is located in West Africa, and its population is mainly rural with very few health services available. Since the earliest times, Guinea-Bissau flora has constituted the main source of materials used in folk medicine and the local population, who is well versed in the uses of these plants and their properties. The aim of this study was to document the existing knowledge and practices related to the treatment of neurological disorders, namely epilepsy and seizures, in Guinea-Bissau and in other West African countries. The results presented from this study provide information not only on the specific plants used to treat neurological disorders, but also on social knowledge brought in by various ethnic groups, each one having its own culture, beliefs and ways of nature appropriation. Taking into account the existing knowledge on the medicinal properties of plants for treatment of neurologic disorders, it is believed that research in the areas of ethnomedicine and ethnopharmacology in Guinea-Bissau can bring promising results capable of adding value to the very rich natural resources of this country of West Africa.展开更多
Some species of the Lathyrus genus are among the most promising crops for marginal lands, with high resilience to drought, flood, and fungal diseases, combined with high yields and seed nutritional value. However, lac...Some species of the Lathyrus genus are among the most promising crops for marginal lands, with high resilience to drought, flood, and fungal diseases, combined with high yields and seed nutritional value. However, lack of knowledge on the mechanisms underlying its outstanding performance and methodologies to identify elite genotypes has hampered its proper use in breeding. Chlorophyl a fast fluorescence transient （JIP test）, was used to evaluate water deficit （WD） resistance in Lathyrus genus. Our results reveal unaltered photochemical values for al studied genotypes showing resistance to mild WD. Under severe WD, two Lathyrus sativus genotypes showed remarkable resilience maintaining the photochemical efficiency, contrary to other genotypes studied. Performance index （PIABS） is the best parameter to screen genotypes with improved performance and grain production under WD. Moreover, we found that JIP indices are good indicators of genotypic grain production under WD. Quantum yield of electron transport （wEo） and efficiency with which＆trapped excitons can move electrons further than QA （c0） revealed as important traits related to improved photosyn-thetic performance and should be exploited in future Lathyrus germplasm improvements. The JIP test herein described showed to be an expeditious tool to screen and to identify elite genotypes with improved drought resistance.展开更多
Salinity is a serious threat to agricultural production. Potato （Solanum tuberosum） is an important food crop characterised for having low to moderate salinity tolerance. Tissue cultures may be relevant to improve s...Salinity is a serious threat to agricultural production. Potato （Solanum tuberosum） is an important food crop characterised for having low to moderate salinity tolerance. Tissue cultures may be relevant to improve salt tolerance in potato through selection of salt-tolerant cell lines and subsequent regeneration of plants. In this work, the authors used the random amplified polymorphic DNA （RAPD） markers to investigate the occurrence of genetic polymorphism in a potato calli line tolerant to 150 mM NaCI. Out of 40 primers screened, eight generated polymorphic patterns that distinguished salt-tolerant line from the control. Although the macroscopic appearance was similar in both lines, ultrastructural study revealed alterations in salt-grown cells. These showed that plastids less differentiated with a lower number of grana had more and larger starch grains than control cells. In conclusion, RAPD analysis revealed that NaCl-adapted line is a somaclonal variant and the ultrastructural study showed changes essentially at the plastids.展开更多
文摘The existence of multigenic families in the mevalonate pathway suggests divergent functional roles for pathway components involved in the biosynthesis of plant sterols. Squalene epoxidases （SQEs） are key components of this pathway, and Squalene Epoxidase 1 （SQE1） has been identified as a fundamental enzyme in this biosynthetic step. In the present work, we extended the characterization of the remaining SQE family members, phylogenetically resolving between true SQEs and a subfamily of SQE-like proteins that is exclusive to Brassicaceae. Functional characterization of true SQE family members, Squalene Epox- idase 2 （SQE2） and Squalene Epoxidase 3 （SQE3）, indicates that SQE3, but not SQE2, contributes to the bulk SQE activity in Arabidopsis, with sqe3-1 mutants accumulating squalene and displaying sensitivity to ter- binafine. We genetically demonstrated that SQE3 seems to play a particularly significant role in embryo development. Also, SQE1 and SQE3 both localize in the endoplasmic reticulum, and SQE3 can functionally complement SQEI. Thus, SQE1 and SQE3 seem to be two functionally unequal redundant genes in the pro- motion of plant SQE activity in Arabidopsis.
文摘Trincadeira and Aragonez are two important grapevine cultivars in the Iberian Peninsula, used for high quality red wines production. Both cultivars are strongly affected by fungal diseases, with consequent high loses on plant productivity and fruit quality. A successful protocol for plant regeneration via somatic embryogenesis (SE) was established for both cultivars allowing further plant improvement based on gene transfer technology. Several factors were evaluated during the three different phases which characterize an SE plant regeneration protocol. The culture room temperature during the induction phase, a parameter usually accepted as standard by most researchers, proved in these trials to significantly affect the embryo induction rates. Concerning embryo conversion, it was specially affected by the embryo developmental stage, by the intensity and duration of the chilling treatment and by the supplementation of conversion culture medium with activated charcoal. The responses obtained, both for induction and conversion, proved to be highly genotype dependent. Calli structure, as well as embryo integrity, was histologically observed, allowing to characterize embryonic and non-embryonic masses and to identify abnormalities on embryo development.
基金supported by the Portuguese Foundation for Science and Technology with the FCT/Ciência 2008 to DB and MMREcologi-cal data presented is an output from the project PTDC/AGR-AAM/73144/2006 funded by the Portuguese Foundation for Science and Technology.
文摘The value of crop wild relatives has long been acknowledged and this wild resource has been used to improve crop performance with clear economic benefits. Sugar beet (Beta vulgaris subsp. vulgaris) is the most economically valuable crop species in the order Caryophyllales, B. vulgaris subsp. maritima being the ancestor of the cultivated beets. The wild species of the genus Beta s.l. are commonly found in coastal areas of Europe and Mediterranean Region, where a rich genetic heritage still exists. Broadening the genetic base of sugar beet by introgression with wild relatives is a growing need regarding the maintenance of ecologically important traits. Since wild relatives have adapted to specific habitats, they constitute an important source of novel traits for the beet breeding pool. So, we conducted a broader research project aiming to delimit taxa and identify priority locations to establish genetic reserves of the wild Beta species occurring in Portugal (Western Iberian Peninsula). The aim of this study was: 1) to identify and characterize the main habitats of these wild Beta species;and 2) to present a review of some genetic tools available for future application in sugar beet breeding. In this review, we have focused on EcoTILLING as a molecular tool to assess DNA polymerphisms in wild populations of Beta and identify candidate genes related to drought and salt tolerance, as well as addressed some issues related to next-generation sequencing (NGS) technologies as a new molecular tool to assess adaptive genetic variation on the wild relatives of sugar beet.
文摘Listeria monocytogenes is a foodborne pathogen capable of surviving under challenging conditions both outside and inside the host. During the transition from exponential to stationary phase it experiences a series of environmental changes that require an appropriate response to maintain cell viability. In this study the autolytic behaviour of a L. monocytogenes strain was investigated by two-dimensional electrophoresis. The study was done at the permissive autolysis temperature, 30℃ and at 20℃, an autolysis non-permissive temperature. An autolytic strain proteome was also compared to a non-autolytic strain at the permissive autolysis temperature. The autolytic strain proteome at 30℃ in comparison to 20℃ evidenced increased synthesis of the P60 autolysin, glycolytic enzymes and proteins related with environmental stress responses. The over-production of P45 autolysin, was observed when the autolytic strain proteome was compared with the non-autolytic strain. The proteomes at the non-permissive temperature and the proteome of the non-autolytic strain were characterized by a diminished synthesis of several stress related proteins. The lack of autolysis seems to be associated to the over-production of proteins linked to fatty acid and amino acid synthesis, transcription regulation and cell morphogenesis as evidenced by the proteome at the non-permissive temperature and the non-autolytic strain. Autolysis proteome evidenced the over-production of P60 autolysins, glycolysis and stress proteins whereas the proteome obtained in conditions of absence of autolysis reveal a completely different group of proteins. Possible targets to activate listerial autolysis were identified.
基金The fieldwork made by B.I.was supported by the Insti-tute for Biodiversity and Protected Areas(IBAP)of Guinea-BissauThe authors are very grateful to Dr.Luísa Nunes for the critical reading of the manuscript and to Philip Havik and Dora Castro from IICTsupported by Portuguese FCT grants:to MMR and MCD[HC/0075/2009],to LC[AFR/117785/2010].
文摘The sub-Saharan region holds a wide variety of indigenous plant species, still offering the possibility to discover very interesting new natural products with potential therapeutic value. Most of the African population depends on traditional medicine for primary health care, however, neurological disorders are often not considered as common diseases and many people with mental illnesses, like epilepsy, are severely affected by health-related stigma and discrimination. Epilepsy is the most common serious chronic brain disorder, estimated to affect at least 10 million people in Africa. Guinea-Bissau is located in West Africa, and its population is mainly rural with very few health services available. Since the earliest times, Guinea-Bissau flora has constituted the main source of materials used in folk medicine and the local population, who is well versed in the uses of these plants and their properties. The aim of this study was to document the existing knowledge and practices related to the treatment of neurological disorders, namely epilepsy and seizures, in Guinea-Bissau and in other West African countries. The results presented from this study provide information not only on the specific plants used to treat neurological disorders, but also on social knowledge brought in by various ethnic groups, each one having its own culture, beliefs and ways of nature appropriation. Taking into account the existing knowledge on the medicinal properties of plants for treatment of neurologic disorders, it is believed that research in the areas of ethnomedicine and ethnopharmacology in Guinea-Bissau can bring promising results capable of adding value to the very rich natural resources of this country of West Africa.
基金support from Fundacao para a Ciência e Tecnologia from Portugal is acknowledged through the research projects PTDC/AGR‐GPL/103285/2008,PTDC/AGR‐GPL/099866/2008,Pest‐OE/EQB/LA0004/2011Research Contracts by the Ciência 2008 programs(S.S.Araújo and M.C.Vaz Patto)
文摘Some species of the Lathyrus genus are among the most promising crops for marginal lands, with high resilience to drought, flood, and fungal diseases, combined with high yields and seed nutritional value. However, lack of knowledge on the mechanisms underlying its outstanding performance and methodologies to identify elite genotypes has hampered its proper use in breeding. Chlorophyl a fast fluorescence transient （JIP test）, was used to evaluate water deficit （WD） resistance in Lathyrus genus. Our results reveal unaltered photochemical values for al studied genotypes showing resistance to mild WD. Under severe WD, two Lathyrus sativus genotypes showed remarkable resilience maintaining the photochemical efficiency, contrary to other genotypes studied. Performance index （PIABS） is the best parameter to screen genotypes with improved performance and grain production under WD. Moreover, we found that JIP indices are good indicators of genotypic grain production under WD. Quantum yield of electron transport （wEo） and efficiency with which＆trapped excitons can move electrons further than QA （c0） revealed as important traits related to improved photosyn-thetic performance and should be exploited in future Lathyrus germplasm improvements. The JIP test herein described showed to be an expeditious tool to screen and to identify elite genotypes with improved drought resistance.
文摘Salinity is a serious threat to agricultural production. Potato （Solanum tuberosum） is an important food crop characterised for having low to moderate salinity tolerance. Tissue cultures may be relevant to improve salt tolerance in potato through selection of salt-tolerant cell lines and subsequent regeneration of plants. In this work, the authors used the random amplified polymorphic DNA （RAPD） markers to investigate the occurrence of genetic polymorphism in a potato calli line tolerant to 150 mM NaCI. Out of 40 primers screened, eight generated polymorphic patterns that distinguished salt-tolerant line from the control. Although the macroscopic appearance was similar in both lines, ultrastructural study revealed alterations in salt-grown cells. These showed that plastids less differentiated with a lower number of grana had more and larger starch grains than control cells. In conclusion, RAPD analysis revealed that NaCl-adapted line is a somaclonal variant and the ultrastructural study showed changes essentially at the plastids.
