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

Control of wind strength and frequency in the Aral Sea basin during the late Holocene

Changing content of detrital input in laminated sediments traced by XRF scanning and microfacies analyses reflect prominent variations in sedimentation processes in the Aral Sea. A high-resolution record of titanium from a core retrieved in the northwestern Large Aral Sea allows a continuous reconstruction of wind strength and frequency in western Central Asia for the past 1500 yr. During AD 450-700, AD 1210-1265, AD 1350-1750 and AD 1800-1975, detrital inputs (bearing titanium) are high, documenting an enhanced early spring atmospheric circulation associated with an increase in intensity of the Siberian High pressure system over Central Asia. In contrast, lower titanium content during AD 1750-1800 and AD 1980-1985 reflects a diminished influence of the Siberian High during early spring with a reduced atmospheric circulation. A moderate circulation characterizes the time period AD 700-1150. Unprecedented weakened atmospheric circulation over western Central Asia are inferred during ca. AD 1180-1210 and AD 1265-1310 with a considerable decrease in dust storm frequency, sedimentation rates, lamination thickness and detrital inputs (screened at 40-μm resolution). Our results are concurrent with changes in the intensity of the Siberian High during the past 1400 yr as reported in the GISP2 Ice Core from Greenland. © 2007 University of Washington

Very high resolution paleosecular variation record for the last ∼ 1200 years from the Aral Sea

A record of geomagnetic paleosecular variation (PSV) spanning the last ∼1200 years has been obtained from two lacustrine sediment cores from the north part of Aral Sea (Kazakhstan). Magnetic susceptibility and NRM intensity have been used for correlating between cores and reconstructing composite core data. The main swings and fine details of declination and inclination records correlate well between both cores. A very high sedimentation rate (up to 25 mm per year) due to recent tectonic activity of the region provides a very high resolution PSV record for the interval from 450 ± 100 years BP to 655 ± 65 years BP. The results which have been dated by eight AMS radiocarbon age determinations, suggest that a 200-400 years secular variation period with amplitudes in declination and inclination up to 10-15° existed regularly during the time interval 0-1200 BP. Amplitudes of the PSV record from Aral Sea are not reduced and smoothed by postdetrital magnetization processes. They adjoin to the historical data model and are considered to represent a reliable paleosecular variation record for the Aral Sea region for the last ∼1200 years

Variability in precipitation, temperature and river runoff in W Central Asia during the past ~2000yrs

The tributary rivers Amu Darya and Syr Darya contribute major amounts of water to the hydrological budget of the endorheic Aral Sea. Processes controlling the flow of water into rivers in the headwater systems in Tien Shan (Kyrgyzstan) and Pamir (Tajikistan) are therefore most relevant. Lake water mineralization is strongly dependent on river discharge and has been inferred from spectrometrically determined gypsum and other salt contents. Comparison of high-resolution mineralization data with tree ring data, other proxies for tracing temperature and snow cover in NW China, and accumulation rates in the Guliya Ice Core indicate that mineralization over the past ~2000. yrs in the Aral Sea reflects snow cover variability and glacier extent in Tien Shan and Pamir (at the NW and W edges of the Tibetan Plateau). Snow cover in W Central Asia is preferentially a winter expression controlled by temperature patterns that impact the moisture-loading capacity over N Europe and NW Asia (Clark et al., 1999). We observed that the runoff, resulting from warmer winter temperatures in W Central Asia and resulting in a reduction of snow cover, decreased between AD 100-300, AD 1150-1250, AD 1380-1450, AD 1580-1680 and during several low frequency events after AD 1800. Furthermore, we observed a negative relationship between the amount of mineralization in the Aral Sea and SW summer monsoon intensity starting with the Little Ice Age. Based on these observations, we conclude that the lake level changes during the past ~. 2000. yrs were mostly climatically controlled. Around AD 200, AD 1400 and during the late 20th century AD, human activities (namely irrigation) may also have synergistically influenced discharge dynamics in the lower river courses. © 2011 Elsevier B.V

Harnessing the Microbiomes of Suppressive Composts for Plant Protection: From Metagenomes to Beneficial Microorganisms and Reliable Diagnostics

Soil-borne diseases cause significant yield losses worldwide, are difficult to treat and often only limited options for disease management are available. It has long been known that compost amendments, which are routinely applied in organic and integrated farming as a part of good agricultural practice to close nutrient cycles, can convey a protective effect. Yet, the targeted use of composts against soil-borne diseases is hampered by the unpredictability of the efficacy. Several studies have identified and/or isolated beneficial microorganisms (i.e., bacteria, oomycetes, and fungi) from disease suppressive composts capable of suppressing pathogens (e.g., Pythium and Fusarium) in various crops (e.g., tomato, lettuce, and cucumber), and some of them have been developed into commercial products. Yet, there is growing evidence that synthetic or complex microbial consortia can be more effective in controlling diseases than single strains, but the underlying molecular mechanisms are poorly understood. Currently, a major bottleneck concerns the lack of functional assays to identify the most potent beneficial microorganisms and/or key microbial consortia from complex soil and compost microbiomes, which can harbor tens of thousands of species. This focused review describes microorganisms, which have been isolated from, amended to or found to be abundant in disease-suppressive composts and for which a beneficial effect has been documented. We point out opportunities to increasingly harness compost microbiomes for plant protection through an integrated systems approach that combines the power of functional assays to isolate biocontrol and plant growth promoting strains and further prioritize them, with functional genomics approaches that have been successfully applied in other fields of microbiome research. These include detailed metagenomics studies (i.e., amplicon and shotgun sequencing) to achieve a better understanding of the complex system compost and to identify members of taxa enriched in suppressive composts. Whole-genome sequencing and complete assembly of key isolates and their subsequent functional profiling can elucidate the mechanisms of action of biocontrol strains. Integrating the benefits of these approaches will bring the long-term goals of employing microorganisms for a sustainable control of plant pathogens and developing reliable diagnostic assays to assess the suppressiveness of composts within reach

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

Hydrochemical properties of the Aral Sea water in summer 2002

AbstractIn August 2002, new hydrochemical and hydrophysical data were collected in the Aral Sea. The survey includes cross-sections in three locations: within the Small Aral close to Tastubek Bay, in the Large Aral at the northern tip that is Tschebas Bay and within the western basin at Chernishov Bay. All three locations represent different stages in the hydrochemical evolution of the Aral Sea.Depth profiles of pressure, temperature, conductivity, pH and dissolved oxygen were measured with a YSI 6600 profiler. Water samples were taken with a Niskin bottle and analyzed for dissolved oxygen and nutrients by standard photometric methods. Major anions and cations were analyzed by ion chromatography and ICP-OES, respectively. Benthic flux experiments were carried out with sediment cores in a batch mode assay on-site.In the Small Aral, the changes in the hydrochemical properties are not as dramatic as in the Large Aral. The Small Aral represents a brackish inland water body with salinities of 1718 g kg−1. The wind-mixed layer reached 8 m during the survey. The salinity is vertically and horizontally almost uniform. Below 8 m, a temporally hypoxic layer forms during summer. Salt redissolution was found to be an important source of salt in the water. About 33.5 g SO42− m−2 day−1 and about 30.7 g Cl− m−2 day−1 are released from the sediment in summer.In the Large Aral, the salinity distribution is uniform in shallow waters (less than 5 m) but varies strongly in deeper water. Tschebas Bay at the northern tip of the large Aral represents a shallow lagoon with a maximum depth of about 6 m. The water column was well mixed down to the bottom (~6 m) having salt concentrations of 82 g kg−1 on average. Almost no gradients in dissolved substances were observed. It is suspected that salinity is balanced by fresher water inflow originating from the Syr Darya flowing south and by groundwater exfiltration. Chernishov Bay in the north of the western basin is meromictic. Below a wind-mixed layer, a very strong pycnocline of 20 g kg−1 per m at 5 m depth isolates the water below from exchanges with the water above and led to the formation of huge anoxic water body down to the bottom at about 25 m depth. Below 10 m, the water contains hydrogen sulphide. The salt concentration increases from 82 g kg−1 in the surface water to 110 g kg−1 at depth. The salt release from the sediment is as high as 1143 g SO42− m−2 day−1 and 1626 g Cl− m−2 day−1. Benthic release of salt is considered as an important source for salt in the bottom water of the western basin and in sustaining the stable density stratification.Author Keywords: Saline lake; Hydrochemistry; Desiccation; Anoxia; Benthic flux; Asia; Kazakhstan; Aral Se