Phytophthora infestans is a destructive plant pathogen best known
for causing the disease that triggered the Irish potato famine and
remains the most costly potato pathogen to manage worldwide.
Identification of P. infestan’s elusive center of origin is critical to
understanding the mechanisms of repeated global emergence of
this pathogen....
Well-functioning food webs are fundamental for sustaining rivers as ecosystems and maintaining associated aquatic and terrestrial communities. The current emphasis on restoring habitat structure-without explicitly considering food webs-has been less successful than hoped in terms of enhancing the status of targeted species and often overlooks important constraints on ecologically effective...
Deciphering the evolution of global climate from the end of the Last Glacial Maximum approximately 19 ka to the early Holocene 11 ka presents an outstanding opportunity for understanding the transient response of Earth's climate system to external and internal forcings. During this interval of global warming, the decay of...
Small RNAs, including microRNAs (miRNAs), small interfering RNAs
(siRNAs), and trans-acting siRNAs (tasiRNAs), control gene expression
and epigenetic regulation. Although the roles of miRNAs and
siRNAs have been extensively studied, their expression diversity
and evolution in closely related species and interspecific hybrids
are poorly understood. Here, we show comprehensive analyses...
Transacting siRNA (tasiRNA) biogenesis in Arabidopsis is initiated
by microRNA (miRNA) –guided cleavage of primary transcripts. In
the case of TAS3 tasiRNA formation, ARGONAUTE7 (AGO7)–
miR390 complexes interact with primary transcripts at two sites,
resulting in recruitment of RNA-DEPENDENT RNA POLYMERASE6
for dsRNA biosynthesis. An extensive screen for Arabidopsis mutants...
Insight into the dependence of benthic communities on biological and physical processes in nearshore pelagic environments, long considered a ``black box,'' has eluded ecologists. In rocky intertidal communities at Oregon coastal sites 80 km apart, differences in abundance of sessile invertebrates, herbivores, carnivores, and macrophytes in the low zone were...
Air trapped in glacial ice offers a means of
reconstructing variations in the concentrations of atmospheric
gases over time scales ranging from anthropogenic
(last 200 yr) to glacial/interglacial (hundreds of thousands of
years). In this paper, we review the glaciological processes by
which air is trapped in the ice and...
Wind-driven coastal ocean upwelling supplies nutrients to the
euphotic zone near the coast. Nutrients fuel the growth of phytoplankton,
the base of a very productive coastal marine ecosystem
[Pauly D, Christensen V (1995) Nature 374:255–257]. Because
nutrient supply and phytoplankton biomass in shelf waters are
highly sensitive to variation in...
This study examines the impact of two decades of neoliberal policy reform on food production and household livelihood security in three West African countries. The rice sectors in The Gambia, Côte d’Ivoire, and Mali are scrutinized as well as cotton and its relationship to sorghum production in Mali. Although market...
Summertime wind stress along the coast of the northwestern United States typically exhibits intraseasonal oscillations (ISOs) with periods from ≈15 to 40 days, as well as fluctuations on the 2- to 6-day “weather-band” and 1-day diurnal time scales. Coastal upwelling of cool, nutrient-rich water is driven by extended periods of...