Effect of seed source on growth and performance of potato (Solanum tuberosum L.)

Twenty Russet Burbank seed lots were collected from four states and one Canadian Province in 1988 and planted in replicated trails at Powell Butte and Hermiston, Oregon as part of a two year study to quantify clonal differences in the cultivar. Samples of each seed lot were concurrently increased and stored under identical conditions at Powell Butte to preclude physiological age differences in seed used for similar plantings in 1989. Non-genetic influences were further reduced in the second year (1989) planting by subjecting seed to a combination of eye-indexing and ELISA testing to eliminate virus infected tubers. It was postulated that any differences in yield and performance observed in 1989 would be primarily genetically related. Significant differences (p = 0.05) were noted in U.S. No. 1 yields at both locations and in total yields at Powell Butte in 1988. Similar plantings in 1989 using standardized seed from the 1988 Powell Butte increase showed significant differences in U.S. No. 1 yields only at Hermiston. However, differences significant at the p = 0.10 level were observed for both total and U.S. No. 1 yields, tuber size distribution, and tuber specific gravity during both years at Hermiston. The range in yields decreased with the use of standardized seed at Powell Butte as expected but increased at Hermiston. Reasons for these seemingly contradictory responses are unclear. If substantial differences in maturity existed among the seed lots/clones, the long growing season at Hermiston would have accentuated yield differences. The 1989 Hermiston season was 20 days longer than in 1988 and could have broadened yield ranges in 1989. It is possible that non-genetic factors such as physiological age and viral infection might have partially masked maturity effects at Hermiston in 1988. The Powell Butte growing season is too short to show strong yield benefits from delayed maturity. Consistent differences in seed lot performance in the absence of non-genetic influences such as seed tuber physiological age and viral content would suggest that useful clonal differences exist. Four seed lots in these studies consistently produced high yields at Powell Butte and three at Hermiston during both years while one produced high yields at both locations. Further, large yield differences were still evident at Hermiston in 1989 in trials planted with virus-tested, identically aged seed. These results suggest that line selection from these seed lots could produce high yielding Russet Burbank clones with good tuber conformation. Additional field trials are needed to fully characterize the nature and importance of these potential clonal differences

Monitoring potato leafroll virus movement in differentially aged potato (Solanum tubersom L.) plants with an immunosorbent direct tissue blotting assay

Potato leafroll virus (PLRV) causes yield and quality losses in potato. PLRV is identified by plant symptoms and serological tests such as an enzyme-linked immunosorbent assay (ELISA). A similar serological test, direct tissue blotting assay (DTBA), was used to detect and monitor PLRV movement in field-inoculated Russet Burbank plants and plant tissues from Russet Burbank and Russet Norkotah seed tubers submitted by growers for winter certification tests. DTBA was as accurate as ELISA and easier to use for detecting tuber-perpetuated PLRV in stems and petioles of plants grown from grower-submitted seed tubers. ELISA detected twice as many PLRV positives as DTBA in leaflet tests. DTBA detected PLRV in tuber tissue but results matched ELISA in only 74% or less of the samples. Results of DTBA tuber tests were sometimes difficult to interpret while stem and petiole results were distinct and unambiguous. As inoculations were delayed later in the season and as plants matured, PLRV infection levels decreased sharply, most often within a two week period in early July. In same-age plants inoculated 43 days after planting but 18 days apart, early inoculation produced higher PLRV levels. Conversely, when same-age plants were inoculated 62 days after planting but 19 days apart, late inoculation produced higher PLRV levels. This discrepancy is not fully understood, but larger tuber size at the later inoculation probably produced a stronger sink for source-to-sink translocation of nutrients and phloem-limited viruses. Results of DTBA winter grow-out tests of summer-infected tubers approximated those of ELISA and visual inspections. Indirect DTBA testing of tubers utilizing stem and petiole tissues from winter growout plants detected more PLRV than directly testing tuber tissue 21 days post inoculation in summer. DTBA detected current season (primary) PLRV less reliably than secondary (tuber-borne) PLRV, similar to reported ELISA results. PLRV infection increased tuber numbers but decreased size. Size reduction was most evident in plants infected early in the season. Average tuber size in healthy plots was always larger than the average tuber size in infected plots. Within an infected plant, small tubers tended to be infected less often than large tubers

Mitochondrial impairment activates the Wallerian pathway through depletion of NMNAT2 leading to SARM1-dependent axon degeneration.

Wallerian degeneration of physically injured axons involves a well-defined molecular pathway linking loss of axonal survival factor NMNAT2 to activation of pro-degenerative protein SARM1. Manipulating the pathway through these proteins led to the identification of non-axotomy insults causing axon degeneration by a Wallerian-like mechanism, including several involving mitochondrial impairment. Mitochondrial dysfunction is heavily implicated in Parkinson's disease, Charcot-Marie-Tooth disease, hereditary spastic paraplegia and other axonal disorders. However, whether and how mitochondrial impairment activates Wallerian degeneration has remained unclear. Here, we show that disruption of mitochondrial membrane potential leads to axonal NMNAT2 depletion in mouse sympathetic neurons, increasing the substrate-to-product ratio (NMN/NAD) of this NAD-synthesising enzyme, a metabolic fingerprint of Wallerian degeneration. The mechanism appears to involve both impaired NMNAT2 synthesis and reduced axonal transport. Expression of WLDS and Sarm1 deletion both protect axons after mitochondrial uncoupling. Blocking the pathway also confers neuroprotection and increases the lifespan of flies with Pink1 loss-of-function mutation, which causes severe mitochondrial defects. These data indicate that mitochondrial impairment replicates all the major steps of Wallerian degeneration, placing it upstream of NMNAT2 loss, with the potential to contribute to axon pathology in mitochondrial disorders

Wolbachia and DNA barcoding insects: patterns, potential and problems

Wolbachia is a genus of bacterial endosymbionts that impacts the breeding systems of their hosts. Wolbachia can confuse the patterns of mitochondrial variation, including DNA barcodes, because it influences the pathways through which mitochondria are inherited. We examined the extent to which these endosymbionts are detected in routine DNA barcoding, assessed their impact upon the insect sequence divergence and identification accuracy, and considered the variation present in Wolbachia COI. Using both standard PCR assays (Wolbachia surface coding protein – wsp), and bacterial COI fragments we found evidence of Wolbachia in insect total genomic extracts created for DNA barcoding library construction. When >2 million insect COI trace files were examined on the Barcode of Life Datasystem (BOLD) Wolbachia COI was present in 0.16% of the cases. It is possible to generate Wolbachia COI using standard insect primers; however, that amplicon was never confused with the COI of the host. Wolbachia alleles recovered were predominantly Supergroup A and were broadly distributed geographically and phylogenetically. We conclude that the presence of the Wolbachia DNA in total genomic extracts made from insects is unlikely to compromise the accuracy of the DNA barcode library; in fact, the ability to query this DNA library (the database and the extracts) for endosymbionts is one of the ancillary benefits of such a large scale endeavor – for which we provide several examples. It is our conclusion that regular assays for Wolbachia presence and type can, and should, be adopted by large scale insect barcoding initiatives. While COI is one of the five multi-locus sequence typing (MLST) genes used for categorizing Wolbachia, there is limited overlap with the eukaryotic DNA barcode region

An evaluation based on the analytic hierarchy process and GGEbiplot on French fry potato genotypes in Yunnan, China

A total of 33 potato (Solanum tuberosum L.) cultivars and breeding clones imported from the United States and two local cultivars (Yunshu 401 and Cooperation 88, CK) were planted and evaluated. To determine their suitability for processing into French fries at five locations (e1-e5) in Yunnan Province, China, we developed a comprehensive evaluation system using the analytical hierarchy process (AHP). Eleven evaluation indicators for French fry quality, yield, and agronomic characteristics with a relative importance (weight coefficients) of 0.483, 0.301 and 0.216, respectively, were used to analyze the 35 potato genotypes (designated g1-g35).The genotypes were ranked and the results revealed that (1) on the average, the 33 potato genotypes imported from the United States showed a lower performance compared to the local cultivars. Compared with the CK, they were classified as not vigorous (Mean 5.11 vs CK 7.75), matured earlier (Mean 5.79 vs CK 1.70), and had a low resistance to late blight (Mean 3735.59 vs CK 1418.55), requiring the use of fungicides to control the disease at the five trial locations. (2) The US cultivar ‘Defender’ (g3) ranked in the top six at all five test locations because it had higher yield (29.56 t h m-2), better fry quality (4.64), higher dry matter content (20.41%), better tuber length/width ratio (1.99), longer tubers (13.57cm), stronger plant vigor (7.17) and higher resistance to late blight (AUDPC: 3134.2). (3) By using GGEbiplot analysis, superior genotypes with high and stable yields were g3 and ‘Echo Russet’ (g33). ‘Yunshu 401’ (g34) and ‘Yukon Gem’ (g4) had high but not stable yields. The ideal test environments and hence experimental locations were Luquan (LQ, e2) and Lijiang (LJ, e4) which resulted in the best discrimination between genotypes among the five experimental locations in Yunnan. Overall, the developed evaluation system based on AHP and GGEbiplot analysis including 11 evaluation indicators for French fry quality, yield and agricultural traits can be a model for evaluation and promotion of new French fry cultivars, and evaluating and selecting the test location

Nanoimprinted distributed feedback lasers of solution processed hybrid perovskites

Hybrid perovskite materials have considerable potential for light emitting devices such as LEDs and lasers. We combine solution processed CH3NH3PbI3 perovskite with UV nanoimprinted polymer gratings to fabricate distributed feedback (DFB) lasers. The lead acetate deposition route is shown to be an effective method for fabricating low-loss waveguides (loss coefficient ~6 cm-1) and highly compatible with the polymer grating substrates. The nanoimprinted perovskite exhibited single-mode band-edge lasing, confirmed by angle-dependent transmission measurements. Depending on the excitation pulse duration the lasing threshold shows a value of 110 μJ/cm2 under nanosecond pumping and 4 μJ/cm2 under femtosecond pumping. We demonstrate further that this laser has excellent stability with a lifetime of 10*8 pulses

Huckleberry Gold: A Specialty Market Potato Cultivar with Purple-Skin, Yellow-Flesh, High Tuber Antioxidants, and Resistance to Potato Cyst Nematode (H1) and Potato virus X (Nb and Rx1)

Huckleberry Gold is a purple-skin, yellow-flesh fresh market cultivar with similar culinary qualities to the market standard Yukon Gold. It has lower specific gravity, sucrose and vitamin C content, but a significantly higher level of tuber antioxidants than Yukon Gold. Notable disease resistant characteristics are Potato virus X resistance based on the presence of molecular markers for the PVX resistance genes, Nb and Rx1. In addition it also has the H1 gene present which confers resistance to the potato cyst nematode, Globodera rostochiensis, which has been confirmed by bioassay to pathotype Ro1. The size profile of Huckleberry Gold is smaller than Yukon Gold, allowing a better fit into specialty markets that are geared to smaller size for fresh use. Huckleberry Gold represents the first purple-skin, yellow-flesh cultivar to come from the Northwest (Tri-State) Potato Variety Development program.This is the publisher’s final pdf. The article is copyrighted by the Potato Association of America and published by Springer. It can be found at: http://link.springer.com/journal/12230Keywords: Solanum tuberosum, Variety, Globodera rostochiensis, PV

A chemical survey of exoplanets with ARIEL

Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planet’s birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25–7.8 μm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10–100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed – using conservative estimates of mission performance and a full model of all significant noise sources in the measurement – using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL – in line with the stated mission objectives – will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio

Acrylamide-Forming Potential and Agronomic Properties of Elite US Potato Germplasm from the National Fry Processing Trial

Processed potato (Solanum tuberosum L.) products, such as chips and French fries, contribute to the dietary intake of acrylamide, a suspected human carcinogen. One of the most promising approaches for reducing its consumption is to develop and commercialize new potato varieties with low acrylamide-forming potential. To facilitate this effort, a National Fry Processing Trial (NFPT) was conducted from 2011 to 2013 in five states. More than 140 advanced breeding lines were evaluated for tuber agronomic traits and biochemical properties from harvest through 8 mo of storage. Thirty-eight and 29 entries had significantly less acrylamide in French fries than standard varieties Russet Burbank and Ranger Russet, with reductions in excess of 50%, after one and 8 mo of storage, respectively. As in previous studies, the glucose content of raw tubers was predictive of acrylamide in finished French fries (R² = 0.64–0.77). Despite its role in acrylamide formation, tuber free asparagine was not significant, potentially because it showed relatively little variation in the NFPT population. Even when glucose was included in the model as a covariate, genotype was highly significant (p = 0.001) for predicting acrylamide, indicating there may be yet-unidentified genetic loci to target in breeding. The NFPT has demonstrated that there exist many elite US breeding lines with low acrylamide-forming potential. Our ongoing challenge is to combine this trait with complex quality attributes required by the fry processing industry.This is the publisher’s final pdf. The published article is copyrighted by the Crop Science Society of America and can be found at: https://dl.sciencesocieties.org/publications/c