Functional Characterization of CsSWEET5a, a Cucumber Hexose Transporter That Mediates the Hexose Supply for Pollen Development and Rescues Male Fertility in Arabidopsis.

Pollen cells require large amounts of sugars from the anther to support their development, which is critical for plant sexual reproduction and crop yield. Sugars Will Eventually be Exported Transporters (SWEETs) have been shown to play an important role in the apoplasmic unloading of sugars from anther tissues into symplasmically isolated developing pollen cells and thereby affect the sugar supply for pollen development. However, among the 17 CsSWEET genes identified in the cucumber (Cucumis sativus L.) genome, the CsSWEET gene involved in this process has not been identified. Here, a member of the SWEET gene family, CsSWEET5a, was identified and characterized. The quantitative real-time PCR and ß-glucuronidase expression analysis revealed that CsSWEET5a is highly expressed in the anthers and pollen cells of male cucumber flowers from the microsporocyte stage (stage 9) to the mature pollen stage (stage 12). Its subcellular localization indicated that the CsSWEET5a protein is localized to the plasma membrane. The heterologous expression assays in yeast demonstrated that CsSWEET5a encodes a hexose transporter that can complement both glucose and fructose transport deficiencies. CsSWEET5a can significantly rescue the pollen viability and fertility of atsweet8 mutant Arabidopsis plants. The possible role of CsSWEET5a in supplying hexose to developing pollen cells via the apoplast is also discussed.

Nutrient controlled release performance of bio-based coated fertilizer enhanced by synergistic effects of liquefied starch and siloxane.

The porous structure and hydrophilicity of coating shells affect the nutrient controlled-release performance of castor oil-based (CO) coated fertilizers. In order to solve these problems, in this study, the castor oil-based polyurethane (PCU) coating material was modified with liquefied starch polyol (LS) and siloxane, and a new coating material with cross-linked network structure and hydrophobic surface was synthesized, and used it to prepare the coated controlled-release urea (SSPCU). The results demonstrated that the cross-linked network formed by LS and CO improved the density and reduced the pores on the surface of the coating shells. The siloxane was grafted on the surface of coating shells to improve its hydrophobicity and thus delayed water entry. The nitrogen release experiment indicated that the synergistic effects of LS and siloxane improved the nitrogen controlled-release performance of bio-based coated fertilizers. Nutrient released longevity of SSPCU with 7 % coating percentage reached >63 days. Moreover, the nutrient release mechanism of coated fertilizer was further revealed by the analysis of the release kinetics analysis. Therefore, the results of this study provide a new idea and technical support for development of efficient and environment-friendly bio-based coated controlled-release fertilizers.

Effect of germination on the main chemical compounds and 5-methyltetrahydrofolate metabolism of different quinoa varieties.

This study determined the content of macronutrients and micronutrients to investigate the nutritional value and health benefits of six varieties of quinoa seeds and sprouts. Germination markedly increased the contents of proteins, reducing sugars, free amino acids, vitamins, and phytochemicals such as phenolic and carotenoid compounds, with variation among different quinoa varieties. Relatively high levels of 5-methyltetrahydrofolate (5-MTHF) were found in 6-day-old quinoa sprouts, especially in the LL-1 variety (1747.25 µg/100 g DW), followed by QL-2 sprouts (1501.67 µg/100 g DW). Furthermore, we examined the relative expression of genes involved in the folate biosynthetic pathway during QL-2 germination. The expression of the ADCS gene was upregulated 28.31-fold in 6-day-old sprouts, greatly facilitating folate synthesis. Pterin synthesis genes regulate the biosynthesis and further accumulation of folate by controlling pterin metabolic flux. Overall, the 6-day-old sprouts were recommended as a functional food with nutritional value and health benefits in dietary supplements.

Synthesis and characterization of carboxymethyl chitosan/epoxidized soybean oil based conjugate catalyed by UV light, and its application as drug carrier for fusarium wilt.

In this paper, a cationic photoinitiator (TAS) was used as a catalyst for the ring opening reaction of carboxymethyl chitosan (CMCS) and epoxidized soybean oil (ESO) under UV light to prepare CMCS-g-ESO conjugate, and the structure of the product was characterized by FT-IR, 1H NMR and GPC. Then, the spinosad-loaded microcapsules (SSD@CMCS-g-ESO) were prepared by ultrasonic self-assembly method. The results showed that TAS could catalyze the ring opening reaction of CMCS and ESO under UV-irradiation and the optimum reaction time was 1 h, with the molecular weight of 15,745. The average particle size of SSD@CMCS-g-ESO was about 2.16 µm, and the encapsulation efficiency (EE) and drug loading content (LC) of SSD@CMCS-g-ESO were 85.39 ± 2.05% and 20.17 ± 1.84%, respectively. In vitro release revealed that SSD@CMCS-g-ESO exhibited sustained-release and pH-responsive property, and the accumulative release in the buffer solution of pH = 6.5 and 7.4 was higher than in pH = 9.0. Furthermore, SSD@CMCS-g-ESO had a good antifungal properties against Fusarium oxysporum f. sp. cubense (Foc) compared with the unencapsulated SSD at the same drug dose. This work indicated that photo-chemical reactions could be used to prepare bio-based carrier materials to construct drugs delivery system for targeted treatment of fusarium wilt.

RNA-Seq Based De Novo Transcriptome Assembly and Gene Discovery of Cistanche deserticola Fleshy Stem.

BACKGROUNDS: Cistanche deserticola is a completely non-photosynthetic parasitic plant with great medicinal value and mainly distributed in desert of Northwest China. Its dried fleshy stem is a crucial tonic in traditional Chinese medicine with roles of mainly improving male sexual function and strengthening immunity, but few mechanistic studies have been conducted partly due to the lack of genomic and transcriptomic resources. RESULTS: In this study, we performed deep transcriptome sequencing in fleshy stem of C. deserticola, and about 80 million reads were generated using Illumina pair-end sequencing on HiSeq2000 platform. Using trinity assembler, we obtained 95,787 transcript sequences with transcript lengths ranging from 200 bp to 15,698 bp, having an average length of 950 bases and the N50 length of 1,519 bases. 63,957 transcripts were identified actively expressed with FPKM ≥ 0.5, in which 30,098 transcripts were annotated with gene descriptions or gene ontology terms by sequence similarity analyses against several public databases (Uniprot, NR and Nt at NCBI, and KEGG). Furthermore, we identified key enzyme genes involved in biosynthesis of lignin and phenylethanoid glycosides (PhGs) which are known to be the primary active ingredients. Four phenylalanine ammonia-lyase (PAL) genes, the first key enzyme in lignin and PhG biosynthesis, were identified based on sequences comparison and phylogenetic analysis. Two biosynthesis pathways of PhGs were also proposed for the first time. CONCLUSIONS: In all, we completed a global analysis of the C. deserticola fleshy stem transcriptome using RNA-seq technology. A collection of enzyme genes related to biosynthesis of lignin and phenylethanoid glysides were identified from the assembled and annotated transcripts, and the gene family of PAL was also predicted. The sequence data from this study will provide a valuable resource for conducting future phenylethanoid glysides biosynthesis researches and functional genomic studies in this important medicinal plant.