Two cold inducible genes encoding lipid transfer protein LTP4 from barley show differential responses to bacterial pathogens

The barley genesHvLtp4.2 andHvLtp4.3 both encode the lipid transfer protein LTP4 and are less than 1 kb apart in tail-to-tail orientation. They differ in their non-coding regions from each other and from the gene corresponding to a previously reportedLtp4 cDNA (nowLtp4.1). Southern blot analysis indicated the existence of three or moreLtp4 genes per haploid genome and showed considerable polymorphism among barley cultivars. We have investigated the transient expression of genesHvLtp4.2 andHvLtp4.3 following transformation by particle bombardment, using promoter fusions to the-glucuronidase reporter sequence. In leaves, activities of the two promoters were of the same order as those of the sucrose synthase (Ss1) and cauliflower mosaic virus 35S promoters used as controls. Their expression patterns were similar, except thatLtp4.2 was more active thanLtp4.3 in endosperm, andLtp4.3 was active in roots, whileLtp4.2 was not. The promoters of both genes were induced by low temperature, both in winter and spring barley cultivars. Northern blot analysis, using theLtp4-specific probe, indicated thatXanthomonas campestris pv.translucens induced an increase over basal levels ofLtp4 mRNA, whilePseudomonas syringae pv.japonica caused a decrease. TheLtp4.3-Gus promoter fusion also responded in opposite ways to these two compatible bacterial pathogens, whereas theLtp4.2-Gus construction did not respond to infectio

Mining the surface proteome of tomato (Solanum lycopersicum) fruit for proteins associated with cuticle biogenesis

The aerial organs of plants are covered by the cuticle, a polyester matrix of cutin and organic solvent-soluble waxes that is contiguous with the polysaccharide cell wall of the epidermis. The cuticle is an important surface barrier between a plant and its environment, providing protection against desiccation, disease, and pests. However, many aspects of the mechanisms of cuticle biosynthesis, assembly, and restructuring are entirely unknown. To identify candidate proteins with a role in cuticle biogenesis, a surface protein extract was obtained from tomato (Solanum lycopersicum) fruits by dipping in an organic solvent and the constituent proteins were identified by several complementary fractionation strategies and two mass spectrometry techniques. Of the ∼200 proteins that were identified, a subset is potentially involved in the transport, deposition, or modification of the cuticle, such as those with predicted lipid-associated protein domains. These include several lipid-transfer proteins, GDSL-motif lipase/hydrolase family proteins, and an MD-2-related lipid recognition domain-containing protein. The epidermal-specific transcript accumulation of several of these candidates was confirmed by laser-capture microdissection and quantitative reverse transcription-PCR (qRT-PCR), together with their expression during various stages of fruit development. This indicated a complex pattern of cuticle deposition, and models for cuticle biogenesis and restructuring are discussed

Earth–ionosphere couplings, magnetic storms, seismic precursors and TLEs: Results and prospects of the [SQUID]2 system in the low-noise underground laboratory of Rustrel-Pays d’Apt.

International audienceHigh sensitivity combined with an ultra-low-noise environment [SQUID]2 magnetometer (Superconducting QUantum Interference Device with Shielding QUalified for Ionosphere Detection) allows the observation of Earth–ionosphere couplings. Namely: – identification of a mesopause resonance mode excitable by P waves or by electric field as during the hour before the Sichuan earthquake (May 2008); – S and T breathing modes of the Earth during quiet magnetic and seismic periods; – worldwide signal integral of magnetic storms including polar contributions; – signals in time correlation with sprites (Transient Luminous Events). These results point to a worldwide network of at least a few stations of a similar typeGrâce à sa sensibilité et son environnement très bas bruit, les couplages Terre–ionosphère sont observables par le magnétomètre [SQUID]2 (Superconducting QUantum Interference Device with Shielding QUalified for Ionosphere Detection). Notamment : – un mode de résonance de la mésopause excitable par les ondes P ou par champ électrique comme dans lmodifier letter apostropheheure précédant le séisme de Sichuan en mai 2008 ; – les modes S et T de respiration du globe pendant des périodes de calme magnétique et sismique ; – lmodifier letter apostropheintégrale mondiale du signal des orages magnétiques y compris les contributions polaires ; – des signaux associés aux sylphes. Ceci permet de modifier d'envisager un réseau mondial de quelques stations de même type