The construction of an Agrobacterium-mediated transformation system of Gynostemma pentaphyllum using the phosphomannose-isomerase/mannose selection system.

In this study, the transformed system mediated by Agrobacterium tumefaciens of Gynostemma pentaphyllum was constructed by using the phosphomannose-isomerase (PMI) gene as a marker. To investigate the cefotaxime sodium salt (Cef) concentration of bacteriostatic medium and the appropriate mannose concentration in the selectable medium, explants of the stems with buds were cultured in a basic medium supplemented with different Cef and mannose concentrations, respectively. After these were optimized, 288 explants were transformed according the protocol described above to verify their availability by using the polymerase chain reaction (PCR), reverse transcription-PCR and chlorophenol red. The results showed that the appropriate Cef concentration for bacteriostatic culture and mannose concentration for selectable culture were 150 mg l-1 and 3 g l-1 for stem with buds, respectively. According to the PCR results, the transformation frequency of stems with buds was 20.49% with a regeneration rate of 29.16%. In future, the CPR assay could be the auxiliary method of choice as it is moderately accurate, but it has good maneuverability and is cost effective for large-scale use.

[Preliminary Study of Lonicera hypoglauca on Germination Conditions of Sand Culture Seeds and Sterilization Method of Sand Culture Seedling Sterilization].

OBJECTIVE: To explore the germination conditions of Lonicera hypoglauca sand culture seeds and the effects of sand culture seedlings sterilization. METHODS: 0.1% HgCl2 with different sterilization time, different illumination time and temperature culture condition were adopted to study the germination conditions of sand culture seeds. Different sterilization treatments and different hardening-seedling days were used to test the sterilization effect of sand culture seedlings. RESULTS: The sterilization effect of the combination of 75% ethanol 30 s + 0.1% HgCl2 5 min on Lonicera hypoglauca seeds was the optimum,with the average pollution rate of 15.56%, and the average germination rate reached 51.11%. The combination of varied temperature-room temperature under light for 12 h/d was the best, with the average germination rate peaked at 75.49%, and the average germination potential reached 68.36%. The treatment of detergent liquor scrub-tap water wash on the part above the hypocotyl, which was sand cultured under the opening condition and had no root, showed the best sterilization effect, with the average pollution rate was zero, and the average survival rate peaked at 100.00%. The sterilization effect of sand culture seedlings, which was disinfected after cleaning by detergent liquor scrub-tap water wash after hardening-seeding for 30 days, was the best, with the average pollution rate of 50.00%, and the average survival rate of 100.00%. CONCLUSION: The best sterilization effect is the combination of 75% ethanol 30 s + 0.1% HgCl2 5 min; Lighting for 12 h/d of varied temperature-room temperature is regarded as the optimum culture condition. The treatment of detergent liquor scrub-tap water wash treatment on the part above the hypocotyl,which is sand cultured under the opening condition and had no root, shows the best sterilization effect. For the sand culture seedlings, before inoculated in subculture medium, should be hardening-seedling for some days and sterilized after detergent liquor scrub-tap water wash.

[Determination of chlorogenic acid and luteoloside in lonicerae flos of different habitats and germplasms].

OBJECTIVE: To establish an UPLC-PDA method for simultaneous determination of chlorogenic acid and luteoloside in Lonicerae Flos. On the basis of developed method, the quality of Lonicerae Flos from nine habitats and two local germplasms introduced from Qufu in Shandong to Wuming in Guangxi was evaluated. METHODS: The analysis was performed on a Waters Acquity UPLC H-Class system. An Acquity UPLC BEH RP18 (100 mm x 2.1 mm,1.7 µm) column was used for all analyses. The investigated compounds were separated with a gradient mobile phase consisting of acetonitrile and 0.4% phosphoric acid solution at a flow rate of 0.2 mL/min, and the detection wavelength was set at 242 nm. RESULTS: The quality of Lonicerae Flos from Qufu was the best among Lonicerae Flos of nine habitats for its content of chlorogenic acid and luteoloside at 35.715 and 1.270 mg/g, respectively. The content of chlorogenic acid and luteoloside in Lonicerae Flos of "Jiufengyihao" and "Shuxing" introduced from Qufu to Wuming both complied with the standard of Chinese Pharmacopoeia (2010 edition). CONCLUSION: The developed UPLC-PDA method is simple, reliable and repeatable, which is helpful for the quality control of Lonicerae Flos. "Jiufengyihao" and "Shuxing" are potential germplasms for the introduction of Lonicerae Flos in Wuming.

Combined small RNA and degradome sequencing reveals novel miRNAs and their targets in response to low nitrate availability in maize.

BACKGROUND AND AIMS: MicroRNAs (miRNAs) play an important role in the responses and adaptation of plants to many stresses including low nitrogen (LN). Characterizing relevant miRNAs will improve our understanding of nitrogen (N) use efficiency and LN tolerance and thus contribute to sustainable maize production. The objective of this study was to identify novel and known miRNAs and their targets involved in the response and adaptation of maize (Zea mays) to LN stress. METHODS: MiRNAs and their targets were identified by combined analysis of deep sequencing of small RNA and degradome libraries. The identity of target genes was confirmed by gene-specific RNA ligase-mediated rapid amplification of 5' cDNA ends (RLM-RACE) and by quantitative expression analysis. KEY RESULTS: Over 150 million raw reads of small RNA and degradome sequence data were generated. A total of 46 unique mature miRNA sequences belonging to 23 maize miRNA families were sequenced. Eighty-five potentially new miRNAs were identified, with corresponding miRNA* also identified for 65 of them. Twenty-five new miRNAs showed >2-fold relative change in response to LN. In addition to known miR169 species, two novel putative miR169 species were identified. Deep sequencing of miRNAs and the degradome, and RLM-RACE and quantitative polymerase chain reaction (PCR) analyses of their targets showed that miRC10- and miRC68-mediated target cleavage may play a major role among miR169 families in the adaptation to LN by maize seedlings. CONCLUSIONS: Small RNA and degradome sequencing combined with quantitative reverse transcription-PCR and RLM-RACE verification enabled the efficient identification of miRNAs and their target genes. The generated data sets and the two novel miR169 species that were identified will contribute to our understanding of the physiological basis of adaptation to LN stress in maize plants.