Development of a stable genetic transformation system in Erigeron breviscapus: a case study with EbYUC2 in relation to leaf number and flowering time.

MAIN CONCLUSION: A stable genetic transformation system for Erigeron breviscapus was developed. We cloned the EbYUC2 gene and genetically transformed it into Arabidopsis thaliana and E. breviscapus. The leaf number, YUC2 gene expression, and the endogenous auxin content in transgenic plants were significantly increased. Erigeron breviscapus is a prescription drug for the clinical treatment of cardiovascular and cerebrovascular diseases. The rosette leaves have the highest content of the major active compound scutellarin and are an important component in the yield of E. breviscapus. However, little is known about the genes related to the leaf number and flowering time of E. breviscapus. In our previous study, we identified three candidate genes related to the leaf number and flowering of E. breviscapus by combining resequencing data and genome-wide association study (GWAS). However, their specific functions remain to be characterized. In this study, we cloned and transformed the previously identified full-length EbYUC2 gene into Arabidopsis thaliana, developed the first stable genetic transformation system for E. breviscapus, and obtained the transgenic plants overexpressing EbYUC2. Compared with wild-type plants, the transgenic plants showed a significant increase in the number of leaves, which was correlated with the increased expression of EbYUC2. Consistently, the endogenous auxin content, particularly indole-3-acetic acid, in transgenic plants was also significantly increased. These results suggest that EbYUC2 may control the leaf number by regulating auxin biosynthesis, thereby laying a foundation for revealing the molecular mechanism governing the leaf number and flowering time of E. breviscapus.

[SSR information in transcriptome of Pinellia ternata].

OBJECTIVE: In order to establish new molecular markers and to design SSR primers,the SSR information was analyzed in the transcriptome of Pinellia ternata. METHODS: The unigenes in transcriptome were filtered and then redundant sequences were removed by the tool of EST-trimmer and cross-match, respectively. Meanwhile, the non-redundant unigenes were examined by the tool of MISA. RESULTS: 14,468 SSRs were found, and these SSRs were distributed in 12 000 unigenes in the examined sequences. Frequency of occurrences for SSRs was 16.24%, and density of distribution was on average 1/4.33 kb in the present study. Di-nucleotide and tri-nucleotide were the major repeated types,accounting for 51.15% and 41.50%, respectively. AG/CT and CCG/CGG were most frequent motifs in di-nucleotide and tri-nucleotide, accounting for 41.54% and 11. 84%, respectively. 87.14% motifs in the length ranged from 12 bp to 20 bp. CONCLUSION: The SSR site in the transcriptome of Pinellia ternata have the characteristics of high frequency of occurrences, type richness, high density and high potential of polymorphism, and these characteristics might be applied in the study on genetic diversity, marker-assisted breeding,and genetic map of Pinellia ternata.

[Determination of selenium in Tricholoma giganteum by flow injection-hydride generation-atomic absorption spectrometry].

Various test conditions and effect factors for the determination of selenium by flow injection-hydride generation-atomic absorption spectrometry were discussed and a method for the determination of selenium in tricholoma giganteum has been developed. The linear range for selenium is 0-50 microg x L(-1). The relative standard deviation is less than 3% and the recovery is 96%-105%. This method is simple, rapid and has been applied to the determination of selenium in tricholoma giganteum with satisfactory results.

[Determination of trace elements in cardiocrinum giganteum by FAAS].

Conditions for simultaneous determination of multi-tract elements in Cardiocrinum giganteum by flame atomic absorption spectrometry were studied. Elements K, Ca, Na, Mg, Fe, Zn, Mn, Cu and Cr in different growth periods of Cardiocrinum giganteum were determined, the relative standard deviation of the method is between 0.20% and 2.1%, and the recovery is between 97.8% and 104.9%. Analytical results were satisfactory. The results showed that some elements essential to human such as Zn, K, Ca, Mg and Mn in Cardiocrinum giganteum are abundant, implying that the nutritive value of Cardiocrinum giganteum is high.