Suchergebnisse

This research was funded by UK Research and Innovation (BBSRC Grant # BB/L011840/1; Ecology and Epidemiology of Infectious Diseases), by the Scottish Government's Rural and Environment Science and Analytical Services (RESAS) Division, and by the James Hutton Institute. ; The aims of this study were: i) to investigate mature plant resistance (MPR) against four strains of Potato virus Y (PVYO, PVYN, PVYNTN and PVYN−Wi) in potato cultivars that differ in maturity (e.g. early or maincrop) at different developmental stages, and ii) to determine whether phloem translocation of photoassimilates at different stages including the source-sink transition influences MPR. The data showed that MPR was functional by the flowering stage in all cultivars, and that the host-pathogen interaction is highly complex, with all three variables (potato cultivar, virus strain and developmental stage of infection) having a significant effect on the outcome. However, virus strain was the most important factor, and MPR was less effective in protecting tubers from recombinant virus strains (PVYNTN and PVYN−Wi). Development of MPR was unrelated to foliar phloem connectivity, which was observed at all developmental stages, but a switch from symplastic to apoplastic phloem unloading early in tuber development may be involved in the prevention of tuber infections with PVYO. Recombinant virus strains were more infectious than parental strains and PVYNTN has a more effective silencing suppressor than PVYO, another factor that may contribute to the efficiency of MPR. The resistance conferred by MPR against PVYO or PVYN may be associated with or enhanced by the presence of the corresponding strain-specific HR resistance gene in the cultivar. ; Publisher PDF ; Peer reviewed

This work is partially supported by the Scottish Government's Rural and Environment Science and Analytical Services (RESAS) Division ; Potato mop-top pomovirus (PMTV) is one of a few viruses that can move systemically in plants in the absence of the capsid protein (CP). Pomoviruses encode the triple gene block genetic module of movement proteins (TGB 1, 2, and 3) and recent research suggests that PMTV RNA is transported either as ribonucleoprotein (RNP) complexes containing TGB1 or encapsidated in virions containing TGB1. Furthermore, there are different requirements for local or systemic (long-distance) movement. Research suggests that nucleolar passage of TGB1 may be important for the long-distance movement of both RNP and virions. Moreover, and uniquely, the long-distance movement of the CP-encoding RNA requires expression of both major and minor CP subunits and is inhibited when only the major CP sub unit is expressed. This paper reviews pomovirus research and presents a current model for RNA movement. ; Publisher PDF ; Peer reviewed

This work was supported by funding from the Scottish Government's Rural and Environmental Science and Analytical Services (RESAS) Division. ; A new source of genetic resistance derived from Solanum tuberosum Group Phureja against Potato virus Y (PVY) was identified and genetically characterised in three diploid biparental potato populations. Segregation data for two populations (05H1 and 08H1) suggested the presence of a single dominant gene for resistance to PVY which, following DaRT analysis of the 08H1 cross, was mapped to chromosome 9. More detailed genetic analysis of resistance utilised a well-characterised SNP-linkage map for the 06H1 population, together with newly generated marker data. In these plants, which have both S. tuberosum Group Phureja and S. tuberosum Group Tuberosum in their pedigree, the resistance was shown to map to chromosome 9 at a locus not previously associated with PVY resistance, although there is evidence for at least one other genetic factor controlling PVY infection. The resistance factor location on chromosome 9 (named as Ry(o)phu) suggests a potential role of NB-LRR genes in this resistance. Phenotypic analysis using a GUS-tagged virus revealed that a small amount of PVY replication occurred in occasional groups of epidermal cells in inoculated leaves of resistant plants, without inducing any visible hypersensitive response. However, the virus did not enter the vascular system and systemic spread was completely prevented. ; Publisher PDF ; Peer reviewed

This work was funded by the BBSRC grant (BB/M004899/1) as part of the ERA-CAPS project HotSol and the Scottish Government Rural and Environment Science and Analytical Services Division as part of the Strategic Research Programme 2016-2021 ; For many commercial potato cultivars, tuber yield is optimal at average daytime temperatures in the range of 14–22 °C. Further rises in ambient temperature can reduce or completely inhibit potato tuber production, with damaging consequences for both producer and consumer. The aim of this study was to use a genetic screen based on a model tuberization assay to identify quantitative trait loci (QTL) associated with enhanced tuber yield. A candidate gene encoding HSc70 was identified within one of the three QTL intervals associated with elevated yield in a Phureja–Tuberosum hybrid diploid potato population (06H1). A particular HSc70 allelic variant was linked to elevated yield in the 06H1 progeny. Expression of this allelic variant was much higher than other alleles, particularly on exposure to moderately elevated temperature. Transient expression of this allele in Nicotiana benthamiana resulted in significantly enhanced tolerance to elevated temperature. An TA repeat element was present in the promoter of this allele, but not in other HSc70 alleles identified in the population. Expression of the HSc70 allelic variant under its native promoter in the potato cultivar Desiree resulted in enhanced HSc70 expression at elevated temperature. This was reflected in greater tolerance to heat stress as determined by improved yield under moderately elevated temperature in a model nodal cutting tuberization system and in plants grown from stem cuttings. Our results identify HSc70 expression level as a significant factor influencing yield stability under moderately elevated temperature and identify specific allelic variants of HSc70 for the induction of thermotolerance via conventional introgression or molecular breeding approaches. ; Publisher PDF ; Peer reviewed

This work was funded by the Scottish Government Rural and Environment Science and Analytical Services Division as part of the Strategic Research Programme 2016-2021, by a GCRF Foundation Awards for Global Agricultural and Food Systems Research funded by the BBSRC project BB/P022553/1 and also received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement number 835704. Research in Prat's lab was funded by the Spanish Ministerio de Economía y Competitividad BIO2015-73019-EXP, and the aligned Japan EIG CONCERT (PIA102017-1) projects. ; Potato tuber formation is a secondary developmental program by which cells in the subapical stolon region divide and radially expand, to further differentiate into starch accumulating parenchyma. Whilst some details of the molecular pathway that signals tuberization are known, important gaps in our knowledge persist. Here the role of a member of the TERMINAL FLOWER 1/ CENTRORADIALIS gene family (termed StCEN ) in the negative control of tuberization is demonstrated for the first time. It is shown that reduced expression of StCEN accelerates tuber formation whereas transgenic lines over‐expressing this gene display delayed tuberization and reduced tuber yield. Protein‐protein interaction studies (yeast two hybrid and bimolecular fluorescence complementation) demonstrate that StCEN binds components of the recently described tuberigen activation complex. Using transient transactivation assays we show that the StSP6A tuberization signal is an activation target of the tuberigen activation complex, and that co‐expression of StCEN blocks StFD‐Like‐1 activation of the StSP6A gene. Transcriptomic analysis of transgenic lines mis‐expressing StCEN identify early transcriptional events in tuber formation. These results demonstrate that StCEN suppresses tuberization by directly antagonizing StSP6A function in stolons, identifying StCEN as a breeding marker to improve tuber initiation and yield, through the selection of genotypes with reduced StCEN expression. ; Publisher PDF ; Peer reviewed

Funding: This work was funded by the Scottish Government Rural and Environment Science and Analytical Services Division as part of the Strategic Research Programme 2016‐2022, by a GCRF Foundation Awards for Global Agricultural and Food Systems Research funded by the BBSRC project BB/P022553/1 (Quickgro) and EPSRC Reference: EP/T01525X/1, GCRF Global Research Translation Awards, Food Security and Health for East Africa, 2019‐2021, and the European Union's Horizon 2020 research and innovation programme ADAPT (Accelerated Development of Multiple‐Stress Tolerant Potato), grant agreement No GA 2020 862‐858 and G2P‐SOL (Linking genetic resources, genomes and phenotypes of Solanaceous crops) grant agreement No 677379. ; Previously, we developed and applied a glasshouse screen for potato tuber yield under heat stress and identified a candidate gene (HSc70) for heat tolerance by genetic analysis of a diploid potato population. Specific allelic variants were expressed at high levels on exposure to moderately elevated temperature due to variations in gene promoter sequence. In this study, we aimed to confirm the results from the glasshouse screen in field trials conducted over several seasons and locations including those in Kenya, Malawi and the UK. We extend our understanding of the HSc70 gene and demonstrate that expression level of HSc70 correlates with tolerance to heat stress in a wide range of wild potato relatives. The physiological basis of the protective effect of HSc70 was explored and we show that genotypes carrying the highly expressed HSc70 A2 allele are protected against photooxidative damage to PSII induced by abiotic stresses. Overall, we show the potential of HSc70 alleles for breeding resilient potato genotypes for multiple environments. ; Publisher PDF ; Peer reviewed