Centella asiatica (L.) is commonly known as Thankuni plant and has ethnobotanical importance in Bangladesh. Present experiment was conceded to investigate the wilt disease of C. asiatica, vegetative growth and molecul...Centella asiatica (L.) is commonly known as Thankuni plant and has ethnobotanical importance in Bangladesh. Present experiment was conceded to investigate the wilt disease of C. asiatica, vegetative growth and molecular characterization of pathogenic fungi. Pathogenic fungus, Fusarium equiseti was identified as a causal agent of wilt disease in C. asiatica. The effect of culture media on the mycelial growth of F. equiseti showed the highest (89.25 mm) on potato dextrose agar (PDA) medium followed by carrot agar (CA) medium and the lowest growth (40.25 mm) was measured in HA medium. The optimal temperature and pH for mycelial growth of F. equiseti were 30°C and 7, respectively. The genetic variation of the selected species of fungi, the internal transcribed spacer (ITS) region was amplified using ITS4 and ITS5 primers and sequenced. The PCR product of the ITS region of F. equiseti was 535 bp. Phylogenetic tree of thirty-seven strains of Fusarium sp. based on the nucleotide sequences of the ITS region using the neighbor-joining method with 1000 bootstrapping indicated that 98% - 100% identity with MN886590.1 JUF0046 (F. equiseti). ITS sequences are generally constant, or show little variation within species, but vary between species in a genus. The ITS region is relatively short and can be easily amplified by PCR using universal single primer pairs. Genetic distance exhibited high level of similarity with identical ITS sequences. To date, no published research articles are found on the molecular identification of F. equiseti, the causal agent of fusarium wilt disease of C. asiatica in Bangladesh.展开更多
文摘Centella asiatica (L.) is commonly known as Thankuni plant and has ethnobotanical importance in Bangladesh. Present experiment was conceded to investigate the wilt disease of C. asiatica, vegetative growth and molecular characterization of pathogenic fungi. Pathogenic fungus, Fusarium equiseti was identified as a causal agent of wilt disease in C. asiatica. The effect of culture media on the mycelial growth of F. equiseti showed the highest (89.25 mm) on potato dextrose agar (PDA) medium followed by carrot agar (CA) medium and the lowest growth (40.25 mm) was measured in HA medium. The optimal temperature and pH for mycelial growth of F. equiseti were 30°C and 7, respectively. The genetic variation of the selected species of fungi, the internal transcribed spacer (ITS) region was amplified using ITS4 and ITS5 primers and sequenced. The PCR product of the ITS region of F. equiseti was 535 bp. Phylogenetic tree of thirty-seven strains of Fusarium sp. based on the nucleotide sequences of the ITS region using the neighbor-joining method with 1000 bootstrapping indicated that 98% - 100% identity with MN886590.1 JUF0046 (F. equiseti). ITS sequences are generally constant, or show little variation within species, but vary between species in a genus. The ITS region is relatively short and can be easily amplified by PCR using universal single primer pairs. Genetic distance exhibited high level of similarity with identical ITS sequences. To date, no published research articles are found on the molecular identification of F. equiseti, the causal agent of fusarium wilt disease of C. asiatica in Bangladesh.
基金Supported by the National Natural Science Foundation of China(No.30900003)the Basic Research Special Project of the Ministry of Science and Technology of China(No.2006FY120100)
文摘目的:优选木贼配方颗粒的喷雾干燥工艺条件,制备合格的中间体,以利于后续干法制粒工序的开展。方法:以出粉率和粒径分布为指标,通过单因素试验筛选辅料种类;利用Minitab 16软件中的Plackett-Burman设计,以出粉率为指标,筛选影响喷雾干燥的3个主要影响因素(进风温度、固含比、进料速度),并确定非主要影响因素的水平。以山柰素转移率、细粉吸湿率和出粉率为指标,利用Box-Behnken优选工艺参数。结果:最佳喷雾干燥工艺条件为3%微粉硅胶加入固含量20%的木贼浸膏中,料液温度65℃,进风温度151℃,进风量4 m3·min^(-1),进料速度33 m L·min^(-1)。山柰素转移率94.2%,喷干粉吸湿率20.6%,出粉率85.0%。结论:优选的喷雾干燥工艺稳定可行,为木贼配方颗粒的大生产提供参考。
