Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white...Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white birch. In this study, we used ultrasound-assisted extraction （UAE） to extract triterpenoids from birch bark rapidly and with high efficiency. Using high performance liquid chro- matography （HPLC）, three types of triterpenoids were separated and detected. We examined the differences among triterpenoids extracted from diploid versus tetra- ploid white birch. Then, we used factor analysis to screen out tetraploid white birches with comprehensively excel- lent performance. The results indicate that the optimum conditions for extraction include the use of ethanol as an extraction solvent, a solid-to-liquid ratio of 0.1 g/10 ml, ultrasonic power set at 100 W, a temperature of 60 ℃ and an extraction time of 15 min. A reversed-phase C18 col- umn （4.6 mm × 250 mm × 5 μm） with a column tem- perature of 30 ℃ and the mobile phase composed of A （acetonitrile） and B （0.1% aqueous phosphoric acid, v/v） at a flow rate of 0.5 ml/min were used, and the detection wavelength was 195 nm. No significant difference wasobserved between diploid and tetraploid white birch in terms of the content of three types of triterpenoids （at a confidence level of 0.05）. As triterpenoid content, height, and DBH （diameter at breast height） are strongly interre- lated, we used factor analysis to evaluate all individuals, and we screened out six plus trees with excellent com- prehensive characters.展开更多
Betula platyphylla Sukaczev tetraploids have significantly larger leaf, fruit and stoma (gigantic phenotype) than diploids of the same species;however, the mechanism underlying this difference remains unclear. Tetrapl...Betula platyphylla Sukaczev tetraploids have significantly larger leaf, fruit and stoma (gigantic phenotype) than diploids of the same species;however, the mechanism underlying this difference remains unclear. Tetraploid B. platyphylla transcriptome data have indicated that the expression of genes related to indole-3-acetic acid (IAA) biosynthesis and signal transduction was altered after genome duplication. IAA exerts pleiotropic effects on growth and development by inducing the expression of Aux/IAA. We identified 20 Aux/IAA genes (BpIAA1– BpIAA20) in B. platyphylla distributed across 10 chromosomes. Multiple alignment and motif analyses revealed that nine BpIAA proteins shared all four conserved domains. Phylogenetic analysis indicated that Aux/IAA families were divided into four subfamilies and that there were two pairs of BpIAA sister genes. The BpIAAs were differentially expressed in diploids and tetraploids. Moreover, the expression levels of the nine BpIAA genes were specifically up-regulated in tetraploids from June to September compared with May (except August 5th) in tetraploids, while they were down-regulated in diploids. IAA levels were more than twofold higher in tetraploids than diploids during the vegetative season. These results indicate that genome duplication of B. platyphylla caused the up-regulated of genes involved in IAA synthesis, and the increased concentration of IAA may induce the constitutive expression of 20 BpIAA genes. Therefore, the significant changes in the expression patterns of the BpIAAs contributed to the gigantic phenotype of tetraploids to some extent. Our research sheds light on the phenotypic variations observed in B. platyphylla tetraploids.展开更多
基金financially supported by National Forestry Department Public Benefit Research Foundation of China(201204302)
文摘Betulin, oleanolic acid, and betulinic acid are naturally occurring pentacyclic triterpenoids that have significant medicinal value. Considerable amounts of these triterpenoids are available in the outer bark of white birch. In this study, we used ultrasound-assisted extraction （UAE） to extract triterpenoids from birch bark rapidly and with high efficiency. Using high performance liquid chro- matography （HPLC）, three types of triterpenoids were separated and detected. We examined the differences among triterpenoids extracted from diploid versus tetra- ploid white birch. Then, we used factor analysis to screen out tetraploid white birches with comprehensively excel- lent performance. The results indicate that the optimum conditions for extraction include the use of ethanol as an extraction solvent, a solid-to-liquid ratio of 0.1 g/10 ml, ultrasonic power set at 100 W, a temperature of 60 ℃ and an extraction time of 15 min. A reversed-phase C18 col- umn （4.6 mm × 250 mm × 5 μm） with a column tem- perature of 30 ℃ and the mobile phase composed of A （acetonitrile） and B （0.1% aqueous phosphoric acid, v/v） at a flow rate of 0.5 ml/min were used, and the detection wavelength was 195 nm. No significant difference wasobserved between diploid and tetraploid white birch in terms of the content of three types of triterpenoids （at a confidence level of 0.05）. As triterpenoid content, height, and DBH （diameter at breast height） are strongly interre- lated, we used factor analysis to evaluate all individuals, and we screened out six plus trees with excellent com- prehensive characters.
基金supported by the National Natural Science Foundation of China(Grant Nos.31370660 and 31670673)the 111 Project(B16010)
文摘Betula platyphylla Sukaczev tetraploids have significantly larger leaf, fruit and stoma (gigantic phenotype) than diploids of the same species;however, the mechanism underlying this difference remains unclear. Tetraploid B. platyphylla transcriptome data have indicated that the expression of genes related to indole-3-acetic acid (IAA) biosynthesis and signal transduction was altered after genome duplication. IAA exerts pleiotropic effects on growth and development by inducing the expression of Aux/IAA. We identified 20 Aux/IAA genes (BpIAA1– BpIAA20) in B. platyphylla distributed across 10 chromosomes. Multiple alignment and motif analyses revealed that nine BpIAA proteins shared all four conserved domains. Phylogenetic analysis indicated that Aux/IAA families were divided into four subfamilies and that there were two pairs of BpIAA sister genes. The BpIAAs were differentially expressed in diploids and tetraploids. Moreover, the expression levels of the nine BpIAA genes were specifically up-regulated in tetraploids from June to September compared with May (except August 5th) in tetraploids, while they were down-regulated in diploids. IAA levels were more than twofold higher in tetraploids than diploids during the vegetative season. These results indicate that genome duplication of B. platyphylla caused the up-regulated of genes involved in IAA synthesis, and the increased concentration of IAA may induce the constitutive expression of 20 BpIAA genes. Therefore, the significant changes in the expression patterns of the BpIAAs contributed to the gigantic phenotype of tetraploids to some extent. Our research sheds light on the phenotypic variations observed in B. platyphylla tetraploids.
