ABSTRACT
Objective: To identify Sarcandra glabra and its adulterants using three DNA molecular markers including 18 S rRNA gene, ITS2 sequence and SCAR marker, and then provide the basis for its molecular authentication. Methods: 18 S rRNA gene sequence of S. glabra was obtained by PCR amplification, cloning and sequencing, and then Blast comparison was made in NCBI. The ITS2 sequence of S. glabra was obtained by PCR amplification, sequencing and annotation in ITS2 Database. In the meanwhile, the ITS2 sequences of adulterants and other plants were collected from GenBank. Using MEGA5.5, the genetic distance was calculated between species and then the ITS2 sequences were aligned to construct a phylogenetic clustering tree. SCAR molecular marker of S. glabra was obtained by RAPD. After cloning and sequencing, specific primers were designed to amplify S. glabra and its adulterants. Results: The length of 18 S rRNA obtained in our research was 1 820 bp. Blast comparison revealed that there was 99% homology between S. glabra and Chloranthaceae, which proved to be 18 S rRNA gene of S. glabra. The length of the ITS2 sequence in our research was 500 bp. Genetic distance between S.glabra and its adulterants ranged from 0.190 to 0.219, which was far more than genetic distance among adulterants (0.000-0.074). Cluster analysis showed that S. glabra and its adulterants respectively clustered into a different branch, which was far away from other plants. In our research, we obtained SCAR molecular marker of S. glabra and then a pair of specific primers were designed. Using the pair of specific primers, specific products were amplified from genomic DNA of S. glabra, but no specific products were obtained from that of its adulterants. Conclusion: We could authenticate S. glabra and its adulterants effectively with the combination of three molecular markers for establishing a novel method to identify S. glabra and its adulterants, which provides a new idea for the authentication of S. glabra.
ABSTRACT
Allelic differences in A and B mating-type loci are a prerequisite for the progression of mating in the genus Pleurotus eryngii; thus, the crossing is hampered by this biological barrier in inbreeding. Molecular markers linked to mating types of P. eryngii KNR2312 were investigated with randomly amplified polymorphic DNA to enhance crossing efficiency. An A4-linked sequence was identified and used to find the adjacent genomic region with the entire motif of the A locus from a contig sequenced by PacBio. The sequence-characterized amplified region marker 7-2299 distinguished A4 mating-type monokaryons from KNR2312 and other strains. A BLAST search of flanked sequences revealed that the A4 locus had a general feature consisting of the putative HD1 and HD2 genes. Both putative HD transcription factors contain a homeodomain sequence and a nuclear localization sequence; however, valid dimerization motifs were found only in the HD1 protein. The ACAAT motif, which was reported to have relevance to sex determination, was found in the intergenic region. The SCAR marker could be applicable in the classification of mating types in the P. eryngii breeding program, and the A4 locus could be the basis for a multi-allele detection marker.
Subject(s)
Breeding , Cicatrix , Classification , Dimerization , DNA , DNA, Intergenic , Inbreeding , Pleurotus , Transcription FactorsABSTRACT
Objective: To reveal the genetic relationship of germplasms of Anoectochilus roxburghii and develop an effective and valuable molecular marker. Methods: In this study the polymorphic random amplified polymorphic DNA (RAPD) and specific SCAR markers were developed based on 20 different germplasms from various places. Results: Twenty-eight 100 RAPD primers have significant polymorphism, generated 135 polymorphic bands among 20 germplasms. On the basis of RAPD results, 20 germplasms were clustered into six groups on genetic distance of 0.748. Conclusion: Clustering analysis shows that there are the significant genetic differences among germplasms derived from different regions. A total of five specific bands from RAPD results are transferred into sequence characterized amplified region (SCAR) markers. Amplified results of SCAR markers among different germplasms show that SCAR markers are significant specific to different germplsms. This study has laid a solid foundation for accelerating the breeding of A. roxburghii.