European Frogbit (Hydrocharis morsus-ranae) in the Champlain/Adirondack Region: Recent Inferences

As part of its north-south movement following introduction to Canada, Hydrocharis morsus-ranae L. (Hydrocharitaceae) has recently become established in slow-moving waters of the Champlain/Adirondack region of the northeastern US. The species is present on both the New York and Vermont shores of Lake Champlain and, so far, at a single location in the interior of the Adirondack Park. The southernmost Champlain/Adirondack occurrence is in the Champlain Canal south of Whitehall, NY (L. Eichler, Darrin Freshwater Institute, pers. comm.), within 25 miles of the Hudson River watershed—a population first recorded around 2006. Entry into the Hudson watershed, whether from the canal or Adirondack headwaters, has the potential to increase the spread of European frogbit well beyond the handful of spot occurrences currently recorded in the rest of the Northeast. The objective of this note is to summarize findings derived from recent student-driven research conducted on the status and biology of H. morsus-ranae in the Champlain/Adirondack region

Expression of a fungal ferulic acid esterase in suspension cultures of tall fescue (Festuca arundinacea) decreases cell wall feruloylation and increases rates of cell wall digestion

In the cell walls of grasses ferulic acid is esterified to arabinosyl residues in arabinoxylans that can then undergo oxidative coupling reactions to form ferulate dehydrodimers, trimers and oligomers which function to cross-link cell-wall polysaccharides, limiting cell wall degradability. Fungal ferulic acid esterase can release both esterified monomeric and dimeric ferulic acids from these cell wall arabinoxylans making the cell wall more susceptible to further enzymatic attack and increasing cell wall degradability. Non-embryogenic cell suspension cultures of Festuca arundinacea expressing a Aspergillus niger ferulic acid esterase (faeA) targeted to either the apoplast, or endoplasmic reticulum under the control of a constitutive actin promoter, or to the vacuole under the control of a soybean heat shock promoter, were established and FAE activity determined in the cells and medium during a growth cycle. Analysis of the ester-linked ferulates of the cell walls showed that all three transformed cell lines had both reduced ferulate levels and increased levels of xylanase mediated release of wall phenolics on autodigestion as well as increased rates of cell wall digestion in a simulated rumen environment, when compared to control non-transformed cells. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11240-017-1168-9) contains supplementary material, which is available to authorized users

Multi-environmental trials reveal genetic plasticity of oat agronomic traits associated with climate variable changes

Although oat cultivation around the Mediterranean basin is steadily increasing, its yield in these regions lags far behind those of Northern Europe. This results mainly from the poor adaptation of current oat cultivars to Mediterranean environments. Local landraces may act as reservoirs of favorable traits that could contribute to increase oat resilience in this region. To aid selection of suitable agro-climate adapted genotypes we integrated genome-wide association approaches with analysis of field assessed phenotypes of genetic variants and of the weight of associated markers across different environmental variables. Association models accounting for oat population structure were applied on either arithmetic means or best linear unbiased prediction (BLUPs) to ensure robust identification of associations with the agronomic traits evaluated. The meta-analysis of the six joint environments (mega-environment) identified several markers associated with several agronomic traits and crown rust severity. Five of these associated markers were located within expressed genes. These associations were only mildly influenced by climatic variables indicating that these markers are good candidates to improve the genetic potential of oat under Mediterranean conditions. The models also highlighted several marker-trait associations, strongly affected by particular climatic variables including high rain pre- or post-heading dates and high temperatures, revealing strong potential for oat adaptation to specific agro-climatic conditions. These results will contribute to increase oat resilience for particular climatic conditions and facilitate breeding for plant adaptation to a wider range of climatic conditions in the current scenario of climate change

Towards take-all control:A C-‐21β oxidase required for acylation of triterpene defence compounds in oat

Oats produce avenacins, antifungal triterpenes that are synthesized in the roots and provide protection against take-all and other soilborne diseases. Avenacins are acylated at the carbon-21 position of the triterpene scaffold, a modification critical for antifungal activity. We have previously characterized several steps in the avenacin pathway, including those required for acylation. However, transfer of the acyl group to the scaffold requires the C-21β position to be oxidized first, by an as yet uncharacterized enzyme. We mined oat transcriptome data to identify candidate cytochrome P450 enzymes that may catalyse C-21β oxidation. Candidates were screened for activity by transient expression in Nicotiana benthamiana. We identified a cytochrome P450 enzyme AsCYP72A475 as a triterpene C-21β hydroxylase, and showed that expression of this enzyme together with early pathway steps yields C-21β oxidized avenacin intermediates. We further demonstrate that AsCYP72A475 is synonymous with Sad6, a previously uncharacterized locus required for avenacin biosynthesis. sad6 mutants are compromised in avenacin acylation and have enhanced disease susceptibility. The discovery of AsCYP72A475 represents an important advance in the understanding of triterpene biosynthesis and paves the way for engineering the avenacin pathway into wheat and other cereals for control of take-all and other diseases

Safe and just operating spaces for regional social-ecological systems

Humanity faces a major global challenge in achieving wellbeing for all, while simultaneously ensuring that the biophysical processes and ecosystem services that underpin wellbeing are exploited within scientifically informed boundaries of sustainability. We propose a framework for defining the safe and just operating space for humanity that integrates social wellbeing into the original planetary boundaries concept (Rockström et al., 2009a,b) for application at regional scales. We argue that such a framework can: (1) increase the policy impact of the boundaries concept as most governance takes place at the regional rather than planetary scale; (2) contribute to the understanding and dissemination of complexity thinking throughout governance and policy-making; (3) act as a powerful metaphor and communication tool for regional equity and sustainability. We demonstrate the approach in two rural Chinese localities where we define the safe and just operating space that lies between an environmental ceiling and a social foundation from analysis of time series drawn from monitored and palaeoecological data, and from social survey statistics respectively. Agricultural intensification has led to poverty reduction, though not eradicated it, but at the expense of environmental degradation. Currently, the environmental ceiling is exceeded for degraded water quality at both localities even though the least well-met social standards are for available piped water and sanitation. The conjunction of these social needs and environmental constraints around the issue of water access and quality illustrates the broader value of the safe and just operating space approach for sustainable development

Use of Probiotics in Pacific Oyster and Manila Clam Aquaculture

Shellfish, like any farmed livestock, may harbor disease-causing pathogens that are harmful to shellfish health and, potentially, human health. Sometimes, disease-causing pathogens, like species of Vibrio and Aeromonas bacteria, directly affect health outcomes. Water used for larval shellfish hatcheries is typically treated by filtration, UV, or ozone which have varying levels of success at consistently reducing bacteria. One concern with these treatment systems is that they may leave organic material behind in the water while also failing to kill all bacteria, leading to increased growth of potentially pathogenic bacteria on the organic material left behind. Outside of the United States, shellfish can also be treated with antibiotics in order to manage these harmful bacteria. Studies have shown that use of these antibiotics has been linked to the development of resistant bacterial strains. Probiotics provide a more environmentally friendly alternative to manage disease risks to successfully rear larvae in bivalve hatcheries