Mining and identification of members of MYB transcription factor family in Lonicera macranthoides / 中国中药杂志

As a large family of transcription factors, the MYB family plays a vital role in regulating flower development. We studied the MYB family members in Lonicera macranthoides for the first time and identified three sequences of 1R-MYB, 47 sequences of R2R3-MYB, two sequences of 3R-MYB, and one sequence of 4R-MYB from the transcriptome data. Further, their physicochemical properties, conserved domains, phylogenetic relationship, protein structure, functional information, and expression were analyzed. The results show that the 53 MYB transcription factors had different conserved motifs, physicochemical properties, structures, and functions in wild type and 'Xianglei' cultivar of L. macranthoides, indicating their conservation and diversity in evolution. The transcript level of LmMYB was significantly different between the wild type and 'Xianglei' cultivar as well as between flowers and leaves, and some genes were specifically expressed. Forty-three out of 53 LmMYB sequences were expressed in both flowers and leaves, and 9 of the LmMYB members showed significantly different transcript levels between the wild type and 'Xianglei' cultivar, which were up-regulated in the wild type. The results provide a theoretical basis for further studying the specific functional mechanism of the MYB family.

Cloning and function analysis of chalcone isomerase gene and chalcone synthase gene in Lonicera macranthoides / 中国中药杂志

In order to explore the functions of genes of key rate-limiting enzymes chalcone isomerase(CHI) and chalcone synthase(CHS) in the biosynthesis of flavonoids in Lonicera macranthoides, this study screened and cloned the cDNA sequences of CHI and CHS genes from the transcriptome data of conventional variety and 'Xianglei' of L. macranthoides. Online bioinformatics analysis software was used to analyze the characteristics of the encoded proteins, and quantitative reverse-transcription polymerase chain reaction(qRT-PCR) to detect the expression of CHI and CHS in different parts of the varieties at different flowering stages. The content of luteo-loside was determined by high performance liquid chromatography(HPLC) and the correlation with the expression of the two genes was analyzed. The results showed that the CHI and CHS of the two varieties contained a 627 bp and 1170 bp open reading frame(ORF), respectively, and the CHI protein and CHS protein were stable, hydrophilic, and non-secretory. qRT-PCR results demonstrated that CHI and CHS of the two varieties were differentially expressed in stems and leaves at different flowering stages, particularly the key stages. Based on HPLC data, luteoloside content was in negative correlation with the relative expression of the genes. Thus, CHI and CHS might regulate the accumulation of flavonoids in L. macranthoides, and the specific functions should be further studied. This study cloned CHI and CHS in L. macranthoides and analyzed their expression for the first time, which laid a basis for investigating the molecular mechanism of the differences in flavonoids such as luteoloside in L. macranthoides and variety breeding.

Screening and characterization of endophytic Bacillus and Paenibacillus strains from medicinal plant Lonicera japonica for use as potential plant growth promoters

Abstract A total of 48 endophytic bacteria were isolated from surface-sterilized tissues of the medicinal plant Lonicera japonica, which is grown in eastern China; six strains were selected for further study based on their potential ability to promote plant growth in vitro (siderophore and indoleacetic acid production). The bacteria were characterized by phylogenetically analyzing their 16S rRNA gene similarity, by examining their effect on the mycelial development of pathogenic fungi, by testing their potential plant growth-promoting characteristics, and by measuring wheat growth parameters after inoculation. Results showed that the number of endophytic bacteria in L. japonica varied among different tissues, but it remained relatively stable in the same tissues from four different plantation locations. Among the three endophytic strains, strains 122 and 124 both had high siderophore production, with the latter showing the highest phosphate solubilization activity (45.6 mg/L) and aminocyclopropane-1-carboxylic acid deaminase activity (47.3 nmol/mg/h). Strain 170 had the highest indoleacetic acid (IAA) production (49.2 mg/L) and cellulase and pectinase activities. After inoculation, most of the six selected isolates showed a strong capacity to promote wheat growth. Compared with the controls, the increase in the shoot length, root length, fresh weight, dry weight, and chlorophyll content was most remarkable in wheat seedlings inoculated with strain 130. The positive correlation between enzyme (cellulose and pectinase) activity and inhibition rate on Fusarium oxysporum, the IAA production, and the root length of wheat seedlings inoculated with each tested endophytic strain was significant in regression analysis. Deformity of pathogenic fungal mycelia was observed under a microscope after the interaction with the endophytic isolates. Such deformity may be directly related to the production of hydrolytic bacterial enzymes (cellulose and pectinase). The six endophytic bacterial strains were identified to be Paenibacillus and Bacillus strains based on the results of 16S rRNA gene sequencing analysis and their physiological and biochemical characteristics. Results indicate the promising application of endophytic bacteria to the biological control of pathogenic fungi and the improvement of wheat crop growth.