NEWS FROM
PHYSIOLOGIA PLANTARUM
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Published monthly on behalf of SPPS by Wiley-Blackwell.
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How tubulins build the structure of barley
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It takes more than just a single type of tubulin, the major subunit of microtubules, to build the structural framework for the developing barley embryo. Expression profiles of 14 different tubulin genes generated by German and Ukrainian scientists have revealed that their levels of expression differed significantly during development. In general, expression of all the tubulin genes peaked at two days after flowering - apparently to sustain mitosis during endosperm formation. A less prominent peak around 8 days after flowering included only some tubulins and is believed to involve cell wall organization. One gene, HvTUA5 had a very distinct expression profile which is apparently associated with shoot establishment.
Read full article free: Radchunk et al. (December 2007) Physiologia Plantarum 131: 571-580
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NEWS IN BRIEF
FROM OTHER JOURNALS
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Pump structure gives hope for salt tolerant crops
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Source: Pedersen et al (13 December 2007) Nature 450: 1111-1115
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Carnivorous fungi hunted with lasso
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Source: Schmidt et al. (14 December 2007) Science 318: 1743
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Scandinavian research institute:
Plant Biology and Forest Genetics, SLU, Uppsala, Sweden
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The overall goal for Department of Plant Biology and Forest Genetics it to develop better crops for the future. From www.vbsg.slu.se
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The Swedish University of Agricultural Sciences - or SLU, its Swedish abbreviation, as they like to call themselves in all languages - is a large research entity with around 2600 employees in four main locations. The strategic areas comprise Food, Animals, Forests, Rural and Urban development and includes a large proportion of the country's best plant research groups. Some of these are located in Umeå at the Umeå Plant Science Centre, which has been covered in a previous article in SPPS Newsletter. The other center for plant research at SLU is the Department of Plant Biology and Forest Genetics, which is located in Uppsala.
The Department employs around 90 people and their research is centered on plants at the genetic and cellular level with the overall aim of improving future crops. To achieve this goal the Department looks into the molecular and genetic processes of development, metabolism and disease and also establish QTL maps of useful traits to facilitate breeding for better crops.
The scientific work is divided into four research programs that each cover several projects. Research program 1 is called Signal Transduction During Growth and Development and among the topics covered is the process of somatic embryogenesis in conifers. Professor Sara von Arnold has been a leading researcher in this field for several years and her aim is dual. First, she wants to explore how embryo development is regulated at the molecular level, and secondly she wants to exploit the information to use somatic embryogenesis as a tool inbreeding programs.
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Somatic embryogenesis is used for vegetative propagation of trees. From www.biology.gatech.edu
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In a recent paper von Arnold and her colleagues discovered that the genetic instability often associated with vegetative propagation in vitro might reflect the ability to adapt to stress. Stability of four variable nuclear microsatellite loci in embryogenic cultures and zygotic embryos was highle variable in Pinus sylvestris, and low genetic stability was associated with higher embryogenic potential. This indicate that genetic instability might give the plants some kind of plasticity, which help widely distributed plants like pine to adapt to stress.
Research program 2 deals with Disease & Stress Biology and studies how plants respond to insects, fungi and viruses. On the viral side, Anders Kvarnheden studies those that cause disease in cereals, including the single-stranded RNA virus Barley yellow dwarf virus and the DNA virus Wheat dwarf virus. The latter can also infect barley and from such an isolate from Turkey, Kvarnheden recently sequenced the complete genome sequence.
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Potato virus A causes necrotic lesions and mosaics on potato leaves. From www.inra.fr
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Eugene Savenkov is also working with viruses but from a different perspective. He studies the consequences of RNA silencing, where viral RNA sequences can become targeted for sequence specific degradation by the plant. This can be exploited to make virus resistant plants that express e.g. a viral coat protein, but the virus seems somehow to be able to counteract the defence mechanism. In a recent paper Savenkov and colleagues investigated the viral genome-linked protein (VPg) from Potato virus A but the results seemed to indicate, that this protein is not directly involved in defending resistance.
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Antisense oligodeoxynucleotides inhibit starch synthesis gene susiba2 (upper row) and changes the appearance of starch granules. From Sun et al (2005) Plant Journal 44:128
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In Research program 3, Metabolic Biology is under investigation. Synthesis and metabolism of lipids, sterols and glycoalkaloids is studied in plants and yeast, whereas starch and lignin synthesis is being manipulated in barley and spruce, respectively. Christer Jansson has recently shown that small antisense oligodeoxynucleotides can sequence specifically inhibit expression of genes involved in starch biosynthesis. Being only 12-25 nucleotides long, they are actively taken up across the plasma membrane by sugar translocators and transported to the seeds, where they affect starch formation.
A similar strategy is exploited by David Clapham for manipulation of lignin in Norway spruce. It is often desirable to reduce the lignin content in order to facilitate paper production and this was recently achieved in five-year old transgenic trees that expressed an antisense version of the cinnamoyl CoA reductase gene. The transgenic plants had a smaller stem but were otherwise normal. However, they exhibited an 8% reduction in lignin content and an altered distribution of lignin subtypes.
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Xanthosoma is grown for its starchy cocyam corms. From en.wikipedia.org
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The remaining Research program 4 is dedicated to Gene Diversity in Crops and Trees and covers the exotic species Xanthosoma from Central America as well as domestic species. Marie Nyman collects Xanthosoma germplasm and aims to produce pathogen-free planting material for distribution to local farmers. Ann Christin Ršnnberg-WŠstljung is mapping quantitative trait loci (QTL) analysis in willow in order to improve production as well as resistance and tolerance traits, whereas Sanna Black-Samuelsson is studying local deciduous trees from a conservation perspective.
You can find more information about the Department of Plant Biology and Forest Genetics at their official homepage.
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