The expression pattern of the Picea glauca Defensin 1 promoter is maintained in Arabidopsis thaliana, indicating the conservation of signalling pathways between angiosperms and gymnosperms*

A 1149 bp genomic fragment corresponding to the 5' non-coding region of the PgD1 (Picea glauca Defensin 1) gene was cloned, characterized, and compared with all Arabidopsis thaliana defensin promoters. The cloned fragment was found to contain several motifs specific to defence or hormonal response, including a motif involved in the methyl jasmonate reponse, a fungal elicitor responsive element, and TC-rich repeat cis-acting element involved in defence and stress responsiveness. A functional analysis of the PgD1 promoter was performed using the uidA (GUS) reporter system in stably transformed Arabidopsis and white spruce plants. The PgD1 promoter was responsive to jasmonic acid (JA), to infection by fungus and to wounding. In transgenic spruce embryos, GUS staining was clearly restricted to the shoot apical meristem. In Arabidopsis, faint GUS coloration was observed in leaves and flowers and a strong blue colour was observed in guard cells and trichomes. Transgenic Arabidopsis plants expressing the PgD1::GUS construct were also infiltrated with the hemibiotrophic pathogen Pseudomonas syringae pv. tomato DC3000. It caused a suppression of defensin expression probably resulting from the antagonistic relationship between the pathogen-stimulated salicylic acid pathway and the jasmonic acid pathway. It is therefore concluded that the PgD1 promoter fragment cloned appears to contain most if not all the elements for proper PgD1 expression and that these elements are also recognized in Arabidopsis despite the phylogenetic and evolutionary differences that separates them

Infrared Resonance Tuning of Nanoslit Antennas with Phase-Change Materials

Phase-change materials (PCMs) have been established as prime candidates for nonvolatile resonance tuning of nanophotonic components based on a large optical contrast between their amorphous and crystalline states. Recently, the plasmonic PCM In3SbTe2 was introduced, which can be switched from an amorphous dielectric state to a crystalline metallic one over the entire infrared spectral range. While locally switching the PCM around metallic nanorod antennas has already been demonstrated, similar tuning of inverse antenna structures (nanoslits) has not yet been investigated. Here, we demonstrate optical resonance tuning of nanoslit antennas with dielectric and plasmonic PCMs. We compare two geometries with fundamentally different resonance tuning mechanisms: tuning the resonance of aluminum slit antennas by change of the refractive index (dielectric PCM Ge3Sb2Te6), and creating slit-like volumes of amorphous In3SbTe2 and modifying the slit geometry directly (plasmonic PCM In3SbTe2). While the tuning range with the plasmonic PCM is about 3.4 μm and only limited by fabrication, the resonances with the dielectric PCM feature a three times larger quality factor compared to resonances obtained with the plasmonic PCM

Application of Osthol Induces a Resistance Response Against Powdery Mildew in Pumpkin Leave

Plants can defend themselves against fungal infection by natural means inducedby biotic and abiotic elicitors. Osthol is a natural compound extracted from dried fruits ofCnidii Monnieri Fructus. In this study, it has been shown to not only be a fungicide withacceptable curative properties (control efficacy of 68.72), but it also showed a significantprophylactic effect (with control efficacy of 77.36) against pumpkin powdery mildew at aconcentration of 100 μg·mL-1. In pumpkin leaves with/or without inoculation ofSphaerotheca fuliginea, osthol treatment induced the accumulation of chitinase andperoxidase and enhanced the transcription of chitinase gene in non-inoculated leaves. Thepotentiation of phenylalanine amonia-lyase activity in leaves by osthol application andfollowing inoculation was absent in that with inoculation or osthol treatment, indicatingthat induced PAL in osthol-pretreated plants was inoculation-mediated. In conclusion, thisnatural compound could induce resistance response in the plant against powdery mildew