Identification and quantification of ‘Candidatus Phytoplasma pyri’ in declining trees of a Swiss cider pear orchard after incision treatment at the stem base

Candidatus Orchards of 30 to >100 years old fruit trees used for cider production are endangered by an accumulation of abiotic and biotic stress factors. Among biotic stress factors, diseases such as pear decline (PD) caused by the bacterial pathogen ' Phytoplasma ' contributes to a weakening and reduced life time of affected trees. Since direct treatment of this disease is not possible, approaches have gained attention, which might lead to an increased resilience against this pathogen, such as incisions of the cambium at the graft union at the stem base. Six 35 years old pear trees () of a Swiss cider production orchard, all affected by mild decline were chosen for this study. Four out of them were treated with 2-4 incisions per tree in February 2016. Symptoms were visually assessed during summer and autumn 2016 and 2017, respectively, and ' P ' measured in branch samples with a newly developed duplex TaqMan qPCR assay. No effect could be determined within these two subsequent growing seasons after treatment. Both, visual assessment of symptoms and qPCR measurement of the pathogen in branches did not show any difference between treated and untreated trees. The sequencing of two marker genes of the pathogen detected in this orchard confirmed its identity as ' ' and revealed that it belongs to the major genotype present in Europe

Pushing forward white lupin as a local source for protein and nitrogen in Central Europe

White lupin (Lupinus albus L.) is a promising leguminous crop. Europe is fully dependent on protein and nitrogen fertilizer imports. This has tremendous negative effects both in Europe and the producing countries, such as loss of terrestrial biodiversity, pollution of freshwater, increase of greenhouse gases and soil acidification. Diverse crop-rotations with a substantial amount of pulses are a proven solution. The protein composition and yield potential of white lupin suggest that it could become the ‘Soy of the North’. Currently, the seed-borne pathogen Colletotrichum lupini is substantially impeding the cultivation of white lupin in Central Europe. We developed a DNA-based diagnostic test to identify and quantify the fungal pathogen in plants and seeds. This technique will allow us to improve our understanding of the Colletotrichum lupini life cycle and, thereby, lay the basis for an advanced resistance breeding approach

A chromosome-scale genome assembly reveals a highly dynamic effector repertoire of wheat powdery mildew

Blumeria graminis f. sp. tritici (B.g. tritici) is the causal agent of the wheat powdery mildew disease. The highly fragmented B.g. tritici genome available so far has prevented a systematic analysis of effector genes that are known to be involved in host adaptation. To study the diversity and evolution of effector genes we produced a chromosome‐scale assembly of the B.g. tritici genome. The genome assembly and annotation was achieved by combining long‐read sequencing with high‐density genetic mapping, bacterial artificial chromosome fingerprinting and transcriptomics. We found that the 166.6 Mb B.g. tritici genome encodes 844 candidate effector genes, over 40% more than previously reported. Candidate effector genes have characteristic local genomic organization such as gene clustering and enrichment for recombination‐active regions and certain transposable element families. A large group of 412 candidate effector genes shows high plasticity in terms of copy number variation in a global set of 36 isolates and of transcription levels. Our data suggest that copy number variation and transcriptional flexibility are the main drivers for adaptation in B.g. tritici. The high repeat content may play a role in providing a genomic environment that allows rapid evolution of effector genes with selection as the driving force

Paleo-sea surface temperature calculations in the equatorial east Atlantic from Mg/Ca ratios in planktic foraminifera: A comparison to sea surface temperature estimates from UK'37, oxygen isotopes, and foraminiferal transfer function

We present two ∼270 kyr paleo-sea surface temperature (SST) records from the Equatorial Divergence and the South Equatorial Current derived from Mg/Ca ratios in the planktic foraminifer Globigerinoides sacculifer. The present study suggests that the magnesium signature of G. sacculifer provides a seasonal SST estimate from the upper ∼50 m of the water column generated during upwelling in austral low-latitude fall/winter. Common to both down-core records is a glacial-interglacial amplitude of ∼3°–3.5°C for the last climatic changes and lower Holocene and glacial oxygen isotope stage 2 temperatures compared with interglacial stage 5.5 and glacial stage 6 temperatures, respectively. The comparison to published SST estimates from alkenones, oxygen isotopes, and foraminiferal transfer function from the same core material pinpoints discrepancies and conformities between methods

Insights from the Paleogene tropical Pacific: Foraminiferal stable isotope and elemental results from Site 1209, Shatsky Rise

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94995/1/palo1207.pd

Deep and bottom water export from the Southern Ocean to the Pacific Ocean over the past 38 million years

The application of radiogenic isotopes to the study of Cenozoic circulation patterns in the South Pacific Ocean has been hampered by the fact that records from only equatorial Pacific deep water have been available. We present new Pb and Nd isotope time series for two ferromanganese crusts that grew from equatorial Pacific bottom water (D137-01, “Nova,” 7219 m water depth) and southwest Pacific deep water (63KD, “Tasman,” 1700 m water depth). The crusts were dated using 10Be/9Be ratios combined with constant Co-flux dating and yield time series for the past 38 and 23 Myr, respectively. The surface Nd and Pb isotope distributions are consistent with the present-day circulation pattern, and therefore the new records are considered suitable to reconstruct Eocene through Miocene paleoceanography for the South Pacific. The isotope time series of crusts Nova and Tasman suggest that equatorial Pacific deep water and waters from the Southern Ocean supplied the dissolved trace metals to both sites over the past 38 Myr. Changes in the isotopic composition of crust Nova are interpreted to reflect development of the Antarctic Circumpolar Current and changes in Pacific deep water circulation caused by the build up of the East Antarctic Ice Sheet. The Nd isotopic composition of the shallower water site in the southwest Pacific appears to have been more sensitive to circulation changes resulting from closure of the Indonesian seaway

Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis

This study investigated the effects of seawater pH (i.e., 8.10, 7.85 and 7.60) and temperature (16 and 19 °C) on (a) the abiotic conditions in the fluid surrounding the embryo (viz. the perivitelline fluid), (b) growth, development and (c) cuttlebone calcification of embryonic and juvenile stages of the cephalopod Sepia officinalis. Egg swelling increased in response to acidification or warming, leading to an increase in egg surface while the interactive effects suggested a limited plasticity of the swelling modulation. Embryos experienced elevated pCO2 conditions in the perivitelline fluid (>3-fold higher pCO2 than that of ambient seawater), rendering the medium under-saturated even under ambient conditions. The growth of both embryos and juveniles was unaffected by pH, whereas 45Ca incorporation in cuttlebone increased significantly with decreasing pH at both temperatures. This phenomenon of hypercalcification is limited to only a number of animals but does not guarantee functional performance and calls for better mechanistic understanding of calcification processes