Two-way shift of wavelength in holographic sensing of organic vapor in nanozeolites dispersed acrylamide photopolymer.

Holographic sensing of alcohol organic vapor is characterized in detail at transmission and reflection geometries in Y nanozeolites dispersed acrylamide photopolymer. The two-way shift of the diffraction spectrum and its temporal evolution with various vapor concentrations are measured. Obvious blueshifts of diffraction spectrum peaks are observed and analyzed in two recording geometries. The competition mechanism between decreasing the average refractive index and swelling the grating fringe space is proposed for exploring the wavelength shift mechanism. In the reflection grating, as organic vapor increases, the redshift after the blueshift of the wavelength peaks are observed clearly. We further demonstrate the significance of this competition mechanism. In the low concentration region, at transmission <700 ppm and reflection <400 ppm in nanozeolites dispersed polymer, the blueshift of the wavelength is a significant factor in identifying an organic vapor with a low refractive index. These experimental results provide a probability for improving the applicability of a holographic sensor. This work can accelerate the development of the holographic sensing strategy and provide a novel identification method for organic vapor.

Molecular cloning and characterization of CrNCED1, a gene encoding 9-cis-epoxycarotenoid dioxygenase in Citrus reshni, with functions in tolerance to multiple abiotic stresses.

Abscisic acid (ABA) is an important stress phytohormone that plays an essential role in mediating the signaling networks associated with plant responses to various abiotic stresses. In the present study, we isolated a gene CrNCED1 encoding the rate-limiting enzyme of ABA synthesis, 9-cis-epoxycarotenoid dioxygenase (NCED), from Citrus reshni. Expression patterns of CrNCED1 varied among different tissues, in which higher levels were measured in the leaves than in the roots. The steady-state mRNA levels of CrNCED1 were progressively elevated by dehydration and ABA, only transiently induced by cold, but not affected by salt. To examine its function in stress tolerance, transgenic tobacco (Nicotiana nudicaulis) plants constitutively overexpressing CrNCED1 were generated, which contained higher ABA levels than the wild type (WT) under both normal growth conditions and drought stress. The transgenic lines displayed enhanced tolerance to dehydration, drought, salt and oxidative stresses when compared with the WT. Lower levels of reactive oxygen species (H2O2 and O2⁻) were detected in the transgenic plants than in the WT under dehydration and salt stress. On the contrary, transcript levels of several genes associated with ROS scavenging, osmoticum adjustment, and water maintenance, and activities of two antioxidant enzymes were higher in the transgenic plants relative to the WT under the dehydration stress. Taken together, CrNCED1 overexpression confers enhanced tolerance to multiple abiotic stresses, which may be, at least in part, ascribed to the positive activation of the stress-responsive genes.

Genome-wide identification of Pistacia R2R3-MYB gene family and function characterization of PcMYB113 during autumn leaf coloration in Pistacia chinensis.

Pistacia chinensis is known for its biodiesel production. Several varieties of this plant have leaves that produce anthocyanin, which is responsible for their reddish coloration in autumn. This reddish hue is what makes them useful as ornamental plants. However, the mechanism of anthocyanin accumulation during autumn leaf coloration remains unclear. R2R3-MYB proteins reportedly regulated anthocyanin biosynthesis in many plant species. Here, we performed a genome-wide analysis and expression profiles of R2R3-MYB transcription factor in Pistacia. A total of 158 R2R3-MYB proteins were identified and grouped into 32 clades. Combining the data from RNA-seq and qRT-PCR, one key gene, EVM0016534, was screened and identified to have the highest correlation with anthocyanin accumulation. It was named PcMYB113 due to its sequence similarity to AtMYB113 and it could bind to the promoter of PcF3H. Furthermore, ectopic expression of PcMYB113 in Arabidopsis promoted the accumulation of anthocyanin in the seed coat, cotyledon, and mature leaves, thus confirming the function of PcMYB113 in anthocyanin biosynthesis. In addition, PcMYB113 had a specifically higher expression in senesced red leaves than in mature green leaves and young red leaves in P. chinensis, thereby suggesting the potential role of PcMYB113 in promoting anthocyanin biosynthesis during autumn leaf coloration. These findings enrich our understanding of the function of R2R3-MYB genes in anthocyanin biosynthesis and autumn leaf coloration.