Under salinity, Vitis spp. rootstocks can mediate salt (NaCl) exclusion from grafted V. vinifera ... more Under salinity, Vitis spp. rootstocks can mediate salt (NaCl) exclusion from grafted V. vinifera scions enabling higher grapevine yields and production of superior wines with lower salt content. Until now, the genetic and mechanistic elements controlling sodium (Na(+) ) exclusion in grapevine were unknown. Using a cross between two Vitis interspecific hybrid rootstocks, we mapped a dominant quantitative trait locus (QTL) associated with leaf Na(+) exclusion (NaE) under salinity stress. The NaE locus encodes six high-affinity potassium transporters (HKT). Transcript profiling and functional characterization in heterologous systems identified VisHKT1;1 as the best candidate gene for controlling leaf Na(+) exclusion. We characterized four proteins encoded by unique VisHKT1;1 alleles from the parents, and revealed that the dominant HKT variants exhibit greater Na(+) conductance with less rectification than the recessive variants. Mutagenesis of VisHKT1;1 and TaHKT1.5-D from bread wheat,...
K + is the most abundant cation in the grape berry. Here we focus on the most recent information ... more K + is the most abundant cation in the grape berry. Here we focus on the most recent information in the long distance transport and partitioning of K + within the grapevine and postulate on the potential role of K + in berry sugar accumulation, berry water relations, cellular growth, disease resistance, abiotic stress tolerance and mitigating senescence. By integrating information from several different plant systems we have been able to generate new hypotheses on the integral functions of this predominant cation and to improve our understanding of how these functions contribute to grape berry growth and ripening. Valuable contributions to the study of K + in membrane stabilization, turgor maintenance and phloem transport have allowed us to propose a mechanistic model for the role of this cation in grape berry development.
Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. Th... more Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. They are predicted to improve shoot salt exclusion by directly catalysing the retrieval of sodium (Na+) and chloride ions (Cl-) from the root xylem. We investigated whether VvCCC from grapevine (Vitis vinifera L.) has a role in salt tolerance by cloning and functionally characterising the gene from Cabernet Sauvignon. Amino acid sequence analysis revealed that VvCCC shares a high degree of similarity with other plant CCCs. A VvCCC-YFP translational fusion protein localised to the Golgi and trans-Golgi network (TGN), not the plasma membrane, when expressed transiently in tobacco (Nicotiana benthamiana) leaves and Arabidopsis thaliana mesophyll protoplasts. AtCCC-GFP from Arabidopsis also localised to Golgi and TGN. In Xenopus laevis oocytes, VvCCC targeted to the plasma membrane where it catalysed bumetanide sensitive 36Cl-, 22Na+ and 86Rb+ uptake, suggesting that VvCCC (like AtCCC) belongs...
Background: Salt tolerance in grapevine is associated with chloride (Cl −) exclusion from shoots;... more Background: Salt tolerance in grapevine is associated with chloride (Cl −) exclusion from shoots; the rate-limiting step being the passage of Cl − between the root symplast and xylem apoplast. Despite an understanding of the physiological mechanism of Cl − exclusion in grapevine, the molecular identity of membrane proteins that control this process have remained elusive. To elucidate candidate genes likely to control Cl − exclusion, we compared the root transcriptomes of three Vitis spp. with contrasting shoot Cl − exclusion capacities using a custom microarray. Results: When challenged with 50 mM Cl − , transcriptional changes of genotypes 140 Ruggeri (shoot Cl − excluding rootstock), K51-40 (shoot Cl − including rootstock) and Cabernet Sauvignon (intermediate shoot Cl − excluder) differed. The magnitude of salt-induced transcriptional changes in roots correlated with the amount of Cl − accumulated in shoots. Abiotic-stress responsive transcripts (e.g. heat shock proteins) were induced in 140 Ruggeri, respiratory transcripts were repressed in Cabernet Sauvignon, and the expression of hypersensitive response and ROS scavenging transcripts was altered in K51-40. Despite these differences, no obvious Cl − transporters were identified. However, under control conditions where differences in shoot Cl − exclusion between rootstocks were still significant, genes encoding putative ion channels SLAH3, ALMT1 and putative kinases SnRK2.6 and CPKs were differentially expressed between rootstocks, as were members of the NRT1 (NAXT1 and NRT1.4), and CLC families. Conclusions: These results suggest that transcriptional events contributing to the Cl − exclusion mechanism in grapevine are not stress-inducible, but constitutively different between contrasting varieties. We have identified individual genes from large families known to have members with roles in anion transport in other plants, as likely candidates for controlling anion homeostasis and Cl − exclusion in Vitis species. We propose these genes as priority candidates for functional characterisation to determine their role in chloride transport in grapevine and other plants.
Chlamydia trachomatis is the microorganism causing the most common sexually transmitted disease i... more Chlamydia trachomatis is the microorganism causing the most common sexually transmitted disease in the UK and Europe. The majority of female infections are asymptomatic and recognized sequelae include pelvic inflammatory disease, infertility, and ectopic pregnancy. Over 1200 sexually active women from two urban centres in the UK were questioned about awareness and knowledge of Chlamydia genito-urinary infection. Awareness was poor, as half of the study population had never heard of Chlamydia. Overall, less than one-quarter demonstrated adequate knowledge regarding transmission, immunity, symptoms, and sequelae. Better knowledge was found in women over the age of 25 years, in those cohabiting, in those with a professional/management occupation, and in those attending family planning clinics. The Chief Medical Officer's Expert Advisory Group on Chlamydia (1998) has recommended opportunistic screening of asymptomatic sexually active women in the UK. This study gives insight into the considerable task facing the Department of Health, as only an informed public will take up the offer of screening. Research is urgently needed to assess the impact of different approaches to education regarding sexually transmitted infection.
The use of version control has become ubiquitous in software development projects. Version contro... more The use of version control has become ubiquitous in software development projects. Version control systems facilitate parallel development and maintenance through branching, the creation of isolated codelines. Merging is a consequence of branching and is the process of integrating codelines. However, there are unanswered questions about the use of version control to support parallel development; in particular, how are branching and merging used in practice? What defines a successful branching and merging strategy? As a first step towards answering these questions, we recruited a diverse sample of 140 version control users to participate in an online survey. In this paper, we present the survey results and 4 key observations about branching and merging practices in software development projects.
Online Learning and Teaching With Technology: Case Studies, Experience, and Practice
ONLINE LEARNING AND TEACHING WITH TECHNOLOGY CASE STUDIES, EXPERIENCE AND PRACTICE EDITED BY DAVI... more ONLINE LEARNING AND TEACHING WITH TECHNOLOGY CASE STUDIES, EXPERIENCE AND PRACTICE EDITED BY DAVID MURPHY, ROB WALKER AND GRAHAM WEBB ... ONLINE LEARNING AND TEACHING WITH TECHNOLOGY... CASE STUDIES, EXPERIENCE ...
Under salinity, Vitis spp. rootstocks can mediate salt (NaCl) exclusion from grafted V. vinifera ... more Under salinity, Vitis spp. rootstocks can mediate salt (NaCl) exclusion from grafted V. vinifera scions enabling higher grapevine yields and production of superior wines with lower salt content. Until now, the genetic and mechanistic elements controlling sodium (Na(+) ) exclusion in grapevine were unknown. Using a cross between two Vitis interspecific hybrid rootstocks, we mapped a dominant quantitative trait locus (QTL) associated with leaf Na(+) exclusion (NaE) under salinity stress. The NaE locus encodes six high-affinity potassium transporters (HKT). Transcript profiling and functional characterization in heterologous systems identified VisHKT1;1 as the best candidate gene for controlling leaf Na(+) exclusion. We characterized four proteins encoded by unique VisHKT1;1 alleles from the parents, and revealed that the dominant HKT variants exhibit greater Na(+) conductance with less rectification than the recessive variants. Mutagenesis of VisHKT1;1 and TaHKT1.5-D from bread wheat,...
K + is the most abundant cation in the grape berry. Here we focus on the most recent information ... more K + is the most abundant cation in the grape berry. Here we focus on the most recent information in the long distance transport and partitioning of K + within the grapevine and postulate on the potential role of K + in berry sugar accumulation, berry water relations, cellular growth, disease resistance, abiotic stress tolerance and mitigating senescence. By integrating information from several different plant systems we have been able to generate new hypotheses on the integral functions of this predominant cation and to improve our understanding of how these functions contribute to grape berry growth and ripening. Valuable contributions to the study of K + in membrane stabilization, turgor maintenance and phloem transport have allowed us to propose a mechanistic model for the role of this cation in grape berry development.
Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. Th... more Plant cation-chloride cotransporters (CCCs) have been implicated in conferring salt tolerance. They are predicted to improve shoot salt exclusion by directly catalysing the retrieval of sodium (Na+) and chloride ions (Cl-) from the root xylem. We investigated whether VvCCC from grapevine (Vitis vinifera L.) has a role in salt tolerance by cloning and functionally characterising the gene from Cabernet Sauvignon. Amino acid sequence analysis revealed that VvCCC shares a high degree of similarity with other plant CCCs. A VvCCC-YFP translational fusion protein localised to the Golgi and trans-Golgi network (TGN), not the plasma membrane, when expressed transiently in tobacco (Nicotiana benthamiana) leaves and Arabidopsis thaliana mesophyll protoplasts. AtCCC-GFP from Arabidopsis also localised to Golgi and TGN. In Xenopus laevis oocytes, VvCCC targeted to the plasma membrane where it catalysed bumetanide sensitive 36Cl-, 22Na+ and 86Rb+ uptake, suggesting that VvCCC (like AtCCC) belongs...
Background: Salt tolerance in grapevine is associated with chloride (Cl −) exclusion from shoots;... more Background: Salt tolerance in grapevine is associated with chloride (Cl −) exclusion from shoots; the rate-limiting step being the passage of Cl − between the root symplast and xylem apoplast. Despite an understanding of the physiological mechanism of Cl − exclusion in grapevine, the molecular identity of membrane proteins that control this process have remained elusive. To elucidate candidate genes likely to control Cl − exclusion, we compared the root transcriptomes of three Vitis spp. with contrasting shoot Cl − exclusion capacities using a custom microarray. Results: When challenged with 50 mM Cl − , transcriptional changes of genotypes 140 Ruggeri (shoot Cl − excluding rootstock), K51-40 (shoot Cl − including rootstock) and Cabernet Sauvignon (intermediate shoot Cl − excluder) differed. The magnitude of salt-induced transcriptional changes in roots correlated with the amount of Cl − accumulated in shoots. Abiotic-stress responsive transcripts (e.g. heat shock proteins) were induced in 140 Ruggeri, respiratory transcripts were repressed in Cabernet Sauvignon, and the expression of hypersensitive response and ROS scavenging transcripts was altered in K51-40. Despite these differences, no obvious Cl − transporters were identified. However, under control conditions where differences in shoot Cl − exclusion between rootstocks were still significant, genes encoding putative ion channels SLAH3, ALMT1 and putative kinases SnRK2.6 and CPKs were differentially expressed between rootstocks, as were members of the NRT1 (NAXT1 and NRT1.4), and CLC families. Conclusions: These results suggest that transcriptional events contributing to the Cl − exclusion mechanism in grapevine are not stress-inducible, but constitutively different between contrasting varieties. We have identified individual genes from large families known to have members with roles in anion transport in other plants, as likely candidates for controlling anion homeostasis and Cl − exclusion in Vitis species. We propose these genes as priority candidates for functional characterisation to determine their role in chloride transport in grapevine and other plants.
Chlamydia trachomatis is the microorganism causing the most common sexually transmitted disease i... more Chlamydia trachomatis is the microorganism causing the most common sexually transmitted disease in the UK and Europe. The majority of female infections are asymptomatic and recognized sequelae include pelvic inflammatory disease, infertility, and ectopic pregnancy. Over 1200 sexually active women from two urban centres in the UK were questioned about awareness and knowledge of Chlamydia genito-urinary infection. Awareness was poor, as half of the study population had never heard of Chlamydia. Overall, less than one-quarter demonstrated adequate knowledge regarding transmission, immunity, symptoms, and sequelae. Better knowledge was found in women over the age of 25 years, in those cohabiting, in those with a professional/management occupation, and in those attending family planning clinics. The Chief Medical Officer's Expert Advisory Group on Chlamydia (1998) has recommended opportunistic screening of asymptomatic sexually active women in the UK. This study gives insight into the considerable task facing the Department of Health, as only an informed public will take up the offer of screening. Research is urgently needed to assess the impact of different approaches to education regarding sexually transmitted infection.
The use of version control has become ubiquitous in software development projects. Version contro... more The use of version control has become ubiquitous in software development projects. Version control systems facilitate parallel development and maintenance through branching, the creation of isolated codelines. Merging is a consequence of branching and is the process of integrating codelines. However, there are unanswered questions about the use of version control to support parallel development; in particular, how are branching and merging used in practice? What defines a successful branching and merging strategy? As a first step towards answering these questions, we recruited a diverse sample of 140 version control users to participate in an online survey. In this paper, we present the survey results and 4 key observations about branching and merging practices in software development projects.
Online Learning and Teaching With Technology: Case Studies, Experience, and Practice
ONLINE LEARNING AND TEACHING WITH TECHNOLOGY CASE STUDIES, EXPERIENCE AND PRACTICE EDITED BY DAVI... more ONLINE LEARNING AND TEACHING WITH TECHNOLOGY CASE STUDIES, EXPERIENCE AND PRACTICE EDITED BY DAVID MURPHY, ROB WALKER AND GRAHAM WEBB ... ONLINE LEARNING AND TEACHING WITH TECHNOLOGY... CASE STUDIES, EXPERIENCE ...
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