Search results for "1183 Plant biology"
showing 10 items of 23 documents
Chaenothecopsis schefflerae (Ascomycota: Mycocaliciales): a widespread fungus on semi-hardened exudates of endemic New Zealand Araliaceae
2017
Ascomycetes specialised to live on hardened plant exudates occur worldwide, but the number of species so far described is relatively small (c.30). Particularly within the genus Chaenothecopsis (Ascomycota:Mycocaliciales), many species produce their ascomata on hardened but still relatively fresh outpourings of conifer resin or angiosperm exudate. Temperate rainforests of New Zealand provide habitat for several endemic Chaenothecopsis species, including Chaenothecopsis schefflerae, which was previously known from a single sample collected from the exudate of Schefflera digitata (Araliaceae) in the early 1980s. Here we show that C.schefflerae is neither lost nor very rare, but occurs sporadic…
Arabidopsis mutant dnd2 exhibits increased auxin and abscisic acid content and reduced stomatal conductance
2019
Arabidopsis thaliana cyclic nucleotide-gated ion channel gene 4 (AtCNGC4) loss-of-function mutant dnd2 exhibits elevated accumulation of salicylic acid (SA), dwarfed morphology, reduced hypersensitive response (HR), altered disease resistance and spontaneous lesions on plant leaves. An orthologous barley mutant, nec1, has been reported to over-accumulate indole-3-acetic acid (IAA) and to exhibit changes in stomatal regulation in response to exogenous auxin. Here we show that the Arabidopsis dnd2 over-accumulates both IAA and abscisic acid (ABA) and displays related phenotypic and physiological changes, such as, reduced stomatal size, higher stomatal density and stomatal index. dnd2 showed i…
UV-screening and springtime recovery of photosynthetic capacity in leaves of Vaccinium vitis-idaea above and below the snow pack
2019
International audience; Evergreen plants in boreal biomes undergo seasonal hardening and dehardening adjusting their photosynthetic capacity and photoprotection; acclimating to seasonal changes in temperature and irradiance. Leaf epidermal ultraviolet (UV)-screening by flavonols responds to solar radiation, perceived in part through increased ultraviolet-B (UV-B) radiation, and is a candidate trait to provide cross-photoprotection. At Hyytiälä Forestry Station, central Finland, we examined whether the accumulation of flavonols was higher in leaves of Vaccinium vitis-idaea L. growing above the snowpack compared with those below the snowpack. We found that leaves exposed to colder temperature…
Arabidopsis RCD1 coordinates chloroplast and mitochondrial functions through interaction with ANAC transcription factors
2019
Reactive oxygen species (ROS)-dependent signaling pathways from chloroplasts and mitochondria merge at the nuclear protein RADICAL-INDUCED CELL DEATH1 (RCD1). RCD1 interacts in vivo and suppresses the activity of the transcription factors ANAC013 and ANAC017, which mediate a ROS-related retrograde signal originating from mitochondrial complex III. Inactivation of RCD1 leads to increased expression of mitochondrial dysfunction stimulon (MDS) genes regulated by ANAC013 and ANAC017. Accumulating MDS gene products, including alternative oxidases (AOXs), affect redox status of the chloroplasts, leading to changes in chloroplast ROS processing and increased protection of photosynthetic apparatus.…
New national and regional bryophyte records, 49
2016
Paper presents couple of new national and regional bryophyte records accross the world, including our new record of Pseudocalliergon lycopodioides in the Carpathians (Czarny Dunajec); the only recent record for the Carpathians.
Bryophyte Species Richness on Retention Aspens Recovers in Time but Community Structure Does Not
2014
Green-tree retention is a forest management method in which some living trees are left on a logged area. The aim is to offer ‘lifeboats’ to support species immediately after logging and to provide microhabitats during and after forest re-establishment. Several studies have shown immediate decline in bryophyte diversity after retention logging and thus questioned the effectiveness of this method, but longer term studies are lacking. Here we studied the epiphytic bryophytes on European aspen (Populus tremula L.) retention trees along a 30-year chronosequence. We compared the bryophyte flora of 102 ‘retention aspens’ on 14 differently aged retention sites with 102 ‘conservation aspens’ on 14 d…
Do plant-based biogeographical regions shape aphyllophoroid fungal communities in Europe?
2018
Aim: Aphyllophoroid fungi are associated with plants, either using plants as a resource (as parasites or decomposers) or as symbionts (as mycorrhizal partners). In spite of their strong association with plants, it is unknown how much plant distributions determine their biogeographical patterns compared with environmental factors such as climate and human land use. In this study, our aims are to (1) describe the spatial diversity patterns of aphyllophoroid fungi in Europe and (2) identify the factors shaping these patterns. Location: Europe, as well as the adjacent Subarctic to Arctic islands (Greenland, Faroe Islands, Iceland, Svalbard), Palestine and the south-east coast of the Caspian Sea…
Effect of resource availability on evolution of virulence and competition in an environmentally transmitted pathogen
2018
Understanding ecological and epidemiological factors driving pathogen evolution in contemporary time scales is a major challenge in modern health management. Pathogens that replicate outside the hosts are subject to selection imposed by ambient environmental conditions. Increased nutrient levels could increase pathogen virulence by pre-adapting for efficient use of resources upon contact to a nutrient rich host or by favouring transmission of fast-growing virulent strains. We measured changes in virulence and competition in Flavobacterium columnare, a bacterial pathogen of freshwater fish, under high and low nutrient levels. To test competition between strains in genotype mixtures, we devel…
Virus found in a boreal lake links ssDNA and dsDNA viruses.
2017
Viruses have impacted the biosphere in numerous ways since the dawn of life. However, the evolution, genetic, structural, and taxonomic diversity of viruses remain poorly understood, in part because sparse sampling of the virosphere has concentrated mostly on exploring the abundance and diversity of dsDNA viruses. Furthermore, viral genomes are highly diverse, and using only the current sequence-based methods for classifying viruses and studying their phylogeny is complicated. Here we describe a virus, FLiP (Flavobacterium-infecting, lipid-containing phage), with a circular ssDNA genome and an internal lipid membrane enclosed in the icosahedral capsid. The 9,174-nt-long genome showed limite…
Production of High Amounts of Hepatotoxin Nodularin and New Protease Inhibitors Pseudospumigins by the Brazilian Benthic Nostoc sp. CENA543
2017
Nostoc is a cyanobacterial genus, common in soils and a prolific producer of natural products. This research project aimed to explore and characterize Brazilian cyanobacteria for new bioactive compounds. Here we report the production of hepatotoxins and new protease inhibitors from benthic Nostoc sp. CENA543 isolated from a small, shallow, saline-alkaline lake in the Nhecolandia, Pantanal wetland area in Brazil. Nostoc sp. CENA543 produces exceptionally high amounts of nodularin-R. This is the first free-living Nostoc that produces nodularin at comparable levels as the toxic, bloom-forming, Nodularia spumigena. We also characterized pseudospumigins A-F, which are a novel family of linear te…