RESUMO
Simple sequence repeat (SSR) and inter-simple sequence repeat (ISSR) markers were used to evaluate genetic diversity among 22 sweet kernel apricot accessions and 12 cultivars in China to provide information on how to improve the utilization of kernel apricot germplasms. The results showed that 10 pairs of SSR primers screened from 40 primer pairs amplified 43 allelic variants, all of which were polymorphic (100%), and 9 ISSR primers selected from 100 primers amplified 67 allelic variants with 50 polymorphic bands (74.63%). There was a relatively distant genetic relationship between the 34 samples, where their genetic similarity coefficient was between 0.62 and 0.99. The UPGMA dendrogram constructed using combined data of the two marker systems separated the genotypes into three main clusters.
Assuntos
Variação Genética , Repetições de Microssatélites , Prunus armeniaca/classificação , Prunus armeniaca/genética , Marcadores Genéticos , Genótipo , Filogenia , Polimorfismo GenéticoRESUMO
We describe here for the first time the alteration of coenzyme specificity of malate dehydrogenase (MDH) from Streptomyces coelicolor A3(2) (ScMDH). In the present study, we replaced four amino acid residues in the Rossmann fold (ßB-αC) region of NADH-dependent ScMDH by site-directed mutagenesis with those of NADPH-dependent MDH (Glu42Gly, Ile43Ser, Pro45Arg, and Ala46Ser). The coenzyme specificity of the mutant enzyme (ScMDH-T4) was examined. Coenzyme specificity of ScMDH-T4 was shifted 2231.3-fold toward NADPH using kcat/Km(coenzyme) as the measurement of coenzyme specificity. Accordingly, the effect of the replacements on coenzyme specificity is discussed. Our work provides further insight into the coenzyme specificity of ScMDH.
Assuntos
Coenzimas/metabolismo , Malato Desidrogenase/genética , Malato Desidrogenase/metabolismo , Streptomyces coelicolor/enzimologia , Streptomyces coelicolor/genética , Sequência de Aminoácidos , Cinética , Modelos Moleculares , Conformação Molecular , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Especificidade por SubstratoRESUMO
Paris polyphylla var. chinensis is a perennial herb with medicinal properties that is widely used in traditional Chinese medicine. However, this plant has been on the edge of extinction during the last few decades because of excessive deforestation based on the intense ethnopharmaceutical interest. We isolated 12 microsatellite loci from a (CT)(n)-enriched genomic library of P. polyphylla var. chinensis. The polymorphism at each locus was analyzed by screening 30 individuals from a natural population. The number of alleles ranged from 2 to 5. The observed and expected heterozygosities ranged from 0.000 to 0.467, with a mean of 0.247, and from 0.383 to 0.662 with a mean of 0.537, respectively. Six loci (Pp1, Pp3, Pp6, Pp7, Pp9, and Pp12) were found to significantly deviate from Hardy-Weinberg equilibrium. This may be due to the small population size, inbreeding or null alleles. Five of the pairwise comparisons (Pp1 and Pp4, Pp2 and Pp5, Pp2 and Pp9, Pp2 and Pp12, Pp11 and Pp12) exhibited significant linkage disequilibrium (P < 0.05). We conclude that these microsatellite markers will be useful for population genetic studies of P. polyphylla var. chinensis.
Assuntos
Variação Genética , Liliaceae/genética , Repetições de Microssatélites/genética , Plantas Medicinais/genética , Loci Gênicos/genética , Marcadores Genéticos , Dados de Sequência MolecularRESUMO
Lycoris radiata is a perennial herb that has been used in traditional Chinese medicine for a long time and has two main medicinal components in its bulb, lycorine and galanthamine. However, the original microsatellite loci have not been developed for any species of Lycoris. Total genomic DNA was extracted from fresh bulbs using a modified CTAB protocol. We isolated 10 microsatellite loci from 21 L. radiata individuals of a natural population from Yellow Mountain in Anhui Province, China. The number of alleles ranged from two to nine. The observed and expected heterozygosities ranged from 0.238 to 0.952 and from 0.455 to 0.784, respectively. One locus significantly deviated from Hardy-Weinberg equilibrium and no significant linkage disequilibrium was found between pairs of loci. Cross-species amplification of these microsatellite loci was characterized in additional five species (L. sprengeri, L. anhuiensis, L. albiflora, L. longituba, and L. chinensis) of Lycoris. The results suggest that these microsatellite markers would contribute to the population genetic studies of L. radiata and other related species.