The grapevine's gene expression analysis reveals two distinct molecular and functional phases that correspond with the green and red grape stages. And researchers have reported the first biochemical evidence that reactive oxygen species accumulate during the colour transition. Stefania Pilati and fellow researchers from the IASMA Research Center, San Michele all'Adige, Italy, investigated ripening Pinot Noir grapes (Vitis vinifera L.) to identify fruit ripening genes and investigate seasonal influences. They found a core set of more than 1,400 ripening-specific genes that fluctuated similarly across three growing seasons and a smaller gene group strongly influenced by climatic conditions.
During the green berry (pre-véraison) phase, numerous genes involved in hormonal signalling and transcriptional regulation were modulated, suggesting large-scale cellular metabolism reprogramming. Auxin, ethylene and light played pivotal roles. During the following ripening (post-véraison) phase, genes for cell-wall organization and biogenesis, carbohydrate and secondary metabolisms, and stress response came into play, whereas photosynthesis was strongly repressed. These transcriptional events tally with the processes of berry softening and accumulation of sugar, colour and aroma compounds, which ultimately determine berry and wine quality. At véraison, the intervening point when grapes slow down their growth and change colour, this study highlighted an oxidative burst involving hydrogen peroxide (H2O2), and an extensive modulation of the enzymatic anti-oxidative network.
Meanwhile, Laurent G. Deluc and colleagues from the University of Nevada, Reno and the Boston University School of Medicine, USA, took a closer look at the V. vinifera Cabernet Sauvignon variety, surveying seven different stages of grape berry development. The team mapped pronounced differences throughout development in messenger-RNA (mRNA) expression for genes that play key functional roles in a host of processes. These included organic and amino acid metabolism, photosynthesis, circadian cycles and pathogen resistance.
In particular, the researchers recorded changes associated with transcription factor expression patterns, abscisic acid (ABA) biosynthesis, and calcium signalling genes that identified candidate factors likely to participate in véraison, or aroma compound production, and in pathway regulation and sequestration of flavonoid compounds. Some mRNAs were observed to decrease or increase specifically throughout ripening and sugar metabolism gene expression pattern analysis revealed an alternative and previously uncharacterised pathway for glucose and triose phosphate production invoked from véraison to mature berries.
Despite the grapevine's importance, genetic cues underlying the biochemical and physical changes during berry and flavour development have lain undiscovered - until now. "The large number of regulatory genes we have identified represents a powerful new resource for dissecting the mechanisms of fruit ripening control in non-climacteric plants", Pilati and co-workers say. Meanwhile, the second team say they have identified "a set of previously unknown genes potentially involved in critical steps associated with fruit development that can now be subjected to functional testing".
Charlotte Webber | alfa
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The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
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Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
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The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
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15.11.2017 | Event News
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22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy