Simple and compact V-cavity semiconductor laser with 50×100 GHz wavelength tuning.

We report simple and compact V-cavity semiconductor laser capable of full-band wavelength tuning. A half-wave coupler is used to obtain high side-mode suppression ratio (SMSR) without any grating or epitaxial regrowth. Temperature induced gain spectrum shift is employed in combination with the Vernier tuning mechanism to extend the wavelength tuning range beyond the free spectral range limit. Wavelength tuning of 50 channels at 100GHz spacing with SMSR up to 38 dB has been demonstrated. We show that with a temperature variation of 35°C, the tuning range can be extended by about 15 nm, in contrast to 0.1 nm/°C for thermo-optic tuning range in grating based lasers. At a fixed temperature, consecutive wavelength tuning of 31 channels was achieved. The response time of the channel switching under the current-tuning regime is measured to be about 20µs. The large tuning range that can cover the full C-band will enable such a simple, compact and potentially low-cost tunable laser to be used in wavelength-agile access and data center networks.

Genome-Wide Identification and Expression Analysis of 1-Aminocyclopropane-1-Carboxylate Synthase (ACS) Gene Family in Chenopodium quinoa.

Ethylene plays an important role in plant development and stress resistance. The rate-limiting enzyme in ethylene biosynthesis is 1-aminocyclopropane-1-carboxylic acid synthase (ACS). C. quinoa (Chenopodium quinoa) is an important food crop known for its strong tolerance to abiotic stresses. However, knowledge regarding the ACS gene family in C. quinoa remains restricted. In this study, we successfully identified 12 ACS genes (CqACSs) from the C. quinoa genome. Through thorough analysis of their sequences and phylogenetic relationships, it was verified that 8 out of these 12 CqACS isozymes exhibited substantial resemblance to ACS isozymes possessing ACS activity. Furthermore, these eight isozymes could be categorized into three distinct groups. The four remaining CqACS genes grouped under category IV displayed notable similarities with AtACS10 and AtACS12, known as amido transferases lacking ACS activity. The CqACS proteins bore resemblance to the AtACS proteins and had the characteristic structural features typically observed in plant ACS enzymes. Twelve CqACS genes were distributed across 8 out of the 18 chromosomes of C. quinoa. The CqACS genes were expanded from segment duplication. Many cis-regulatory elements related with various abiotic stresses, phytohormones, and light were found. The expression patterns of ACS genes varied across different tissues of C. quinoa. Furthermore, the analysis of gene expression patterns under abiotic stress showed that CqACS genes can be responsive to various stresses, implying their potential functions in adapting to various abiotic stresses. The findings from this research serve as a foundation for delving deeper into the functional roles of CqACS genes.

Comparative Analysis of Six Chloroplast Genomes in Chenopodium and Its Related Genera (Amaranthaceae): New Insights into Phylogenetic Relationships and the Development of Species-Specific Molecular Markers.

Species within the genus Chenopodium hold significant research interest due to their nutritional richness and salt tolerance. However, the morphological similarities among closely related species and a dearth of genomic resources have impeded their comprehensive study and utilization. In the present research, we conduct the sequencing and assembly of chloroplast (cp) genomes from six Chenopodium and related species, five of which were sequenced for the first time. These genomes ranged in length from 151,850 to 152,215 base pairs, showcased typical quadripartite structures, and encoded 85 protein-coding genes (PCGs), 1 pseudogene, 37 tRNA genes, and 8 rRNA genes. Compared with the previously published sequences of related species, these cp genomes are relatively conservative, but there are also some interspecific differences, such as inversion and IR region contraction. We discerned 929 simple sequence repeats (SSRs) and a series of highly variable regions across 16 related species, predominantly situated in the intergenic spacer (IGS) region and introns. The phylogenetic evaluations revealed that Chenopodium is more closely related to genera such as Atriplex, Beta, Dysphania, and Oxybase than to other members of the Amaranthaceae family. These lineages shared a common ancestor approximately 60.80 million years ago, after which they diverged into distinct genera. Based on InDels and SNPs between species, we designed 12 pairs of primers for species identification, and experiments confirmed that they could completely distinguish 10 related species.

Genome-Wide Identification, Expression and Interaction Analyses of PP2C Family Genes in Chenopodium quinoa.

Plant protein phosphatase 2Cs (PP2Cs) function as inhibitors in protein kinase cascades involved in various processes and are crucial participants in both plant development and signaling pathways activated by abiotic stress. In this study, a genome-wide study was conducted on the CqPP2C gene family. A total of putative 117 CqPP2C genes were identified. Comprehensive analyses of physicochemical properties, chromosome localization and subcellular localization were conducted. According to phylogenetic analysis, CqPP2Cs were divided into 13 subfamilies. CqPP2Cs in the same subfamily had similar gene structures, and conserved motifs and all the CqPP2C proteins had the type 2C phosphatase domains. The expansion of CqPP2Cs through gene duplication was primarily driven by segmental duplication, and all duplicated CqPP2Cs underwent evolutionary changes guided by purifying selection. The expression of CqPP2Cs in various tissues under different abiotic stresses was analyzed using RNA-seq data. The findings indicated that CqPP2C genes played a role in regulating both the developmental processes and stress responses of quinoa. Real-time quantitative reverse transcription PCR (qRT-PCR) analysis of six CqPP2C genes in subfamily A revealed that they were up-regulated or down-regulated under salt and drought treatments. Furthermore, the results of yeast two-hybrid assays revealed that subfamily A CqPP2Cs interacted not only with subclass III CqSnRK2s but also with subclass II CqSnRK2s. Subfamily A CqPP2Cs could interact with CqSnRK2s in different combinations and intensities in a variety of biological processes and biological threats. Overall, our results will be useful for understanding the functions of CqPP2C in regulating ABA signals and responding to abiotic stress.

Ethylene-induced NbMYB4L is involved in resistance against tobacco mosaic virus in Nicotiana benthamiana.

Several MYB transcription factors are known to play important roles in plant resistance to environmental stressors. However, the mechanism governing the involvement of MYBs in regulating tobacco mosaic virus (TMV) resistance in plants is still unclear. In this study, we found that not only is Nicotiana benthamiana MYB4-like involved in defence against TMV, but also that the ethylene pathway participates in MYB4L-mediated resistance. Transcription of NbMYB4L was up-regulated in N. benthamiana infected with TMV. Silencing of NbMYB4L led to intensified TMV replication, whereas overexpression of NbMYB4L induced significant resistance to TMV. Transcription of NbMYB4L was greater in 1-aminocyclopropanecarboxylic acid (ACC, ethylene precursor)-pretreated plants but lower when the ethylene signalling pathway was blocked during TMV infection. Gene expression analysis showed that the transcription of NbMYB4L was largely suppressed in ETHYLENE INSENSITIVE 3-like 1(EIL1)-silenced plants. The results of electrophoretic mobility shift assay and chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR) experiments indicated that NbEIL1 could directly bind to two specific regions of the NbMYB4L promoter. Furthermore, a luciferase assay revealed that NbEIL1 significantly induced the reporter activity of the MYB4L promoter in N. benthamiana. These results point to NbEIL1 functioning as a positive regulator of NbMYB4L transcription in N. benthamiana against TMV. Collectively, our work reveals that EIL1 and MYB4L constitute a coherent feed-forward loop involved in the robust regulation of resistance to TMV in N. benthamiana.

Genome-Wide Identification and Expression Analysis of the ß-Amylase Gene Family in Chenopodium quinoa.

ß-Amylase (BAM) is an important starch hydrolase, playing a role in a variety of plant growth and development processes. In this study, 22 BAM gene family members (GFMs) were identified in quinoa (Chenopodium quinoa), an ancient crop gaining modern consumer acceptance because of its nutritional qualities. The genetic structure, phylogenetic and evolutionary relationships, and expression patterns of CqBAM GFMs in different tissues, were analyzed. Phylogenetic analyses assigned the CqBAMs, AtBAMs, and OsBAMs into four clades. The CqBAM gene family had expanded due to segmental duplication. RNA-seq analysis revealed expression of the duplicated pairs to be similar, with the expression of CqBAM GFM pairs showing a degree of tissue specificity that was confirmed by reverse transcription quantitative PCR (RT-qPCR). Several CqBAM GFMs were also responsive to abiotic stresses in shoots and/or roots. In conclusion, the BAM gene family in quinoa was identified and systematically analyzed using bioinformatics and experimental methods. These results will help to elucidate the evolutionary relationship and biological functions of the BAM gene family in quinoa.

OsBBX14 promotes photomorphogenesis in rice by activating OsHY5L1 expression under blue light conditions.

In rice, OsBBX14, a B-box (BBX) transcription factor, reportedly delays heading. Here, we revealed that OsBBX14 positively regulates rice photomorphogenesis. The OsBBX14-overexpressing (OsBBX14-OX) seedlings were hypersensitive to light, especially blue light, and exhibited dwarfism, while the OsBBX14 knock-out plants (osbbx14) were taller than wild-type plants under blue light. Histological analyses indicated that the observed dwarfism was mainly due to decreased cell length. Additionally, OsBBX14 abundance (mRNA and protein levels) was influenced by different light wavelengths in a time-dependent manner. The expression levels of HY5Ls (LONG HYPOCOTYL 5 LIKE) and ELIPs (EARLY LIGHT-INDUCIBLE PROTEIN) genes, whose Arabidopsis thaliana homologs function as positive regulators in the light signaling pathway, were significantly upregulated in OsBBX14-OX lines. In contrast, the expression of genes related to cell wall organization and dwarfism was downregulated in OsBBX14-OX lines. Chromatin immunoprecipitation (ChIP) assays confirmed that OsBBX14 binds to the T/G-box of HY5L1 (LONG HYPOCOTYL 5 LIKE 1) promoter. LUC complementation imaging (LCI) results suggested that OsBBX14 had physical interaction with OsCRY2 protein. Collectively, in response to blue light, OsBBX14 promotes photomorphogenesis, probably by directly or indirectly regulating the expression of HY5L1 or other genes related to cell wall organization and dwarfism.

[Anti-tumor effect of ethanol extracts from Thymus quinquecostatus Celak on human leukemia cell line].

OBJECTIVE: To screen the anti-tumor fraction of ethanol extracts from Thymus quinquecostatus Celak and investigate its anti-tumor effect on human leukemia cell line. METHODS: Ethyl acetate, n-butanol and acetone fractions were separated from the ethanol extracts of wild Thymus quinquecostatus Celak. Growth inhibiting effects of these extracts on human leukemia cell lines K562 and HL-60 were determined by live cell counting and cell growth curve analysis. The possible anti-tumor mechanism was studied by morphological analysis with norcantharidin as a positive control. RESULTS: Ethyl acetate fraction could significantly inhibit the proliferations of K562 and HL-60 cells, and the inhibiting effect depended on the concentration of ethyl acetate fraction. Ethyl acetate fraction could induce apoptosis of K562 and HL-60 cells. The n-butanol and acetone fractions had no significant inhibiting effect on K562 and HL-60 cells. CONCLUSION: Ethyl acetate fraction is the major anti-tumor fraction in ethanol extracts from Thymus quinquecostatus Celak.

Functional validation of Phragmites communis glutathione reductase (PhaGR) as an essential enzyme in salt tolerance.

Reed plants (Phragmites communis (Linn.) Trin) are hydrophilic perennial grasses growing in fresh and brackish waters. These plants readily adapt to arid and high salinity conditions; however, their resistance mechanism against abiotic stresses, especially high salinity, is largely unknown. In the present study, we cloned a glutathione reductase gene from P. communis and investigated its role in conferring salt tolerance in reed plants. The expression of PhaGR at the transcriptional level was affected by multiple abiotic stresses including NaCl, Cd(2+), heat, cold, PEG 6000, and abscisic acid (ABA). Furthermore, NaCl and Cd(2+) could increase its expressions at the translational level. NaCl and Cd(2+) also increased the biosynthesis of soluble protein and reduced glutathione (GSH). Reed seedlings that were challenged with NaCl showed higher levels of GR activities, which corroborated our gene expression data. The increase in GR possibly increased the salt tolerance of reed plants through GSH production. Thus, PhaGR is a potential target gene in improving the salt tolerance of crops through genetic manipulation.

[Original studies on anti-tumor and immunological effect of extracts from Thymus quinquecostatus Celak in mice].

OBJECTIVE: To study the anti-tumor and immunological effect of extracts from Thymus quinquecostatus Celak on mice transplanted S180 tumor cells. METHODS: Different doses of volatile oil and alcohol extracted substances from Thymus quinquecostatus Celak were given to mice bearing S180 tumor for 9 days. Tumor inhibition rates and coefficients of spleen and thymus were determined. RESULTS: Tumor inhibition rates of the groups with alcohol extracts (40 g crude drug.kg(-1).d(-1) and 20 g crude drug.kg(-1).d(-1)) were 51.5% (P<0.01) and 36.4% (P<0.05) respectively, and those of the groups with volatile oil (40 g crude drug.kg(-1).d(-1) and 20 g crude drug.kg(-1).d(-1))were both 39.4% (P<0.05). CONCLUSION: The extracts from Thymus quinquecostatus Celak have anti-tumor activities. The coefficient of spleen in group with alcohol extracts (40 g crude drug.kg(-1).d(-1))was close to normal value, and its coefficient of thymus was between that of the negative control group and the group with cyclophosphamide (0.02 g.kg(-1).d(-1)). The anti-tumor activity of the alcohol extracts was significantly higher than that of the control group and the tumor inhibition rate was depending on drug concentration. Depending on index of immunity,the extracts from Thymus quinquecostatus Celak may have some influences on immunity.

Molecular cloning and characterization of a vacuolar H+ -pyrophosphatase gene, SsVP, from the halophyte Suaeda salsa and its overexpression increases salt and drought tolerance of Arabidopsis.

The chenopodiaceae Suaeda salsa L. is a leaf succulent euhalophyte. Shoots of the S. salsa are larger and more succulent when grown in highly saline environments. This increased growth and water uptake has been correlated with a large and specific cellular accumulation of sodium. S. salsa does not have salt glands or salt bladders on its leaves. Thus, this plant must compartmentalize the toxic Na(+) in the vacuoles. The ability to compartmentalize sodium may result from a stimulation of the proton pumps that provide the driving force for increased sodium transport into the vacuole. In this work, we isolated the cDNA of the vacuolar membrane proton-translocating inorganic pyrophosphatase (H(+) -PPase) from S. salsa. The SsVP cDNA contains an uninterrupted open reading frame of 2292 bp, coding for a polypeptide of 764 amino acids. Northern blotting analysis showed that SsVP was induced in salinity treated leaves. The activities of both the V-ATPase and the V-PPase in Arabidopsis overexpressing SsVP-2 is higher markedly than in wild-type plant under 200 mM NaCl and drought stresses. The Overexpression of SsVP can increase salt and drought tolerance of transgenic Arabidopsis.