Mapping of the gene in tomato conferring resistance to root-knot nematodes at high soil temperature

Root-knot nematodes (RKNs, Meloidogyne spp.) can cause severe yield losses in tomatoes. The Mi-1.2 gene in tomato confers resistance to the Meloidogyne species M. incognita, M. arenaria and M. javanica, which are prevalent in tomato growing areas. However, this resistance breaks down at high soil temperatures (>28°C). Therefore, it is imperative that new resistance sources are identified and incorporated into commercial breeding programmes. We identified a tomato line, MT12, that does not have Mi-1.2 but provides resistance to M. incognita at 32°C soil temperature. An F2 mapping population was generated by crossing the resistant line with a susceptible line, MT17; the segregation ratio showed that the resistance is conferred by a single dominant gene, designated RRKN1 (Resistance to Root-Knot Nematode 1). The RRKN1 gene was mapped using 111 Kompetitive Allele Specific PCR (KASP) markers and characterized. Linkage analysis showed that RRKN1 is located on chromosome 6 and flanking markers placed the locus within a 270 kb interval. These newly developed markers can help pyramiding R-genes and generating new tomato varieties resistant to RKNs at high soil temperature

Genomic-Assisted Marker Development Suitable for CsCvy-1 Selection in Cucumber Breeding

Cucumber is a widely grown vegetable crop plant and a host to many different plant pathogens. Cucumber vein yellowing virus (CVYV) causes economic losses on cucumber crops in Mediterranean countries and in some part of India such as West Bengal and in African countries such as Sudan. CVYV is an RNA potyvirus transmitted mechanically and by whitefly (Bemisia tabaci) in a semipersistent manner. Control of this virus is heavily dependent on the management of the insect vector and breeding virus-resistant lines. DNA markers have been used widely in conventional plant breeding programs via marker-assisted selection (MAS). However, very few resistance sources against CVYV in cucumber exist, and also the lack of tightly linked molecular markers to these sources restricts the rapid generation of resistant lines. In this work, we used genomics coupled with the bulked segregant analysis method and generated the MAS-friendly Kompetitive allele specific PCR (KASP) markers suitable for CsCvy-1 selection in cucumber breeding using a segregating F2 mapping population and commercial plant lines. Variant analysis was performed to generate single-nucleotide polymorphism (SNP)-based markers for mapping the population and genotyping the commercial lines. We fine-mapped the region by generating new markers down to 101 kb with eight genes. We provided SNP data for this interval, which could be useful for breeding programs and cloning the candidate genes

Genome sequence data from 17 accessions of Ensete ventricosum, a staple food crop for millions in Ethiopia.

Published online: 11 Mar 2018We present raw sequence reads and genome assemblies derived from 17 accessions of the Ethiopian orphan crop plant enset (Ensete ventricosum (Welw.) Cheesman) using the Illumina HiSeq and MiSeq platforms. Also presented is a catalogue of single-nucleotide polymorphisms inferred from the sequence data at an average density of approximately one per kilobase of genomic DNA

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

On the mechanisms governing gas penetration into a tokamak plasma during a massive gas injection

A new 1D radial fluid code, IMAGINE, is used to simulate the penetration of gas into a tokamak plasma during a massive gas injection (MGI). The main result is that the gas is in general strongly braked as it reaches the plasma, due to mechanisms related to charge exchange and (to a smaller extent) recombination. As a result, only a fraction of the gas penetrates into the plasma. Also, a shock wave is created in the gas which propagates away from the plasma, braking and compressing the incoming gas. Simulation results are quantitatively consistent, at least in terms of orders of magnitude, with experimental data for a D 2 MGI into a JET Ohmic plasma. Simulations of MGI into the background plasma surrounding a runaway electron beam show that if the background electron density is too high, the gas may not penetrate, suggesting a possible explanation for the recent results of Reux et al in JET (2015 Nucl. Fusion 55 093013)

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Metabolic engineering of thermophilic bacillus species

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN029061 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Circadian Rhythm Regulates Growth of a Biotrophic Pathogen on Arabidopsis Thaliana

Most organisms have an internal biological clock, called the circadian rhythm. The clock is synchronized by the day–night cycle, allowing the organism to accommodate the daily cycles of light and dark attributable to the Earth’s rotation. Circadian clocks have three basic properties, they: have a period length of about 24 hours, can be reset by environmental factors such as light and temperature, and have at least one internal autonomous circadian oscillator. These oscillators contain positive and negative elements that form autoregulatory feedback loops, and in many cases these loops are used to generate 24-hour timing circuits. Identification of clock-regulated genes leads to the determination of the common elements that regulate these genes. If these common elements can be identified, it enables the search for the same elements in potential virulence factors. This would give us information on whether the virulence factors are also regulated by the circadian rhythm. Since the link between plant immune system and the circadian clock has been identified, it is imperative that we identify the link between the pathogenicity factors and the circadian rhythm. Arabidopsis thaliana and its natural biotrophic pathogen Hyaloperonospora arabidopsidis (Hpa) have been used as a model system for this study. Pathogen growth has been investigated under normal (light–dark cycle) and different light conditions (light–light and dark–dark cycles) to understand whether the circadian rhythm has an effect on pathogenicity. In addition, RNA-seq experiments were performed to elucidate differentially expressed genes in both plant and the pathogen