Genome-Wide Association Study to Identify Favorable SNP Allelic Variations and Candidate Genes That Control the Timing of Spring Bud Flush of Tea (Camellia sinensis) Using SLAF-seq.

The timing of spring bud flush (TBF) is of economic importance for tea plant (Camellia sinensis) breeding. We employed a genome-wide association study (GWAS) to identify favorable single nucleotide polymorphism (SNP) allelic variations as well as candidate genes that control TBF of C. sinensis using specific-locus-amplified fragment sequencing (SLAF-seq) in a diversity panel comprising 151 tea plant germplasm resources. GWAS analysis revealed 26 SNPs associated with TBF in three years, and we eventually identified a final significant SNP for TBF. To identify candidate genes possibly related to TBF, we screened seven candidate genes within 100 kb regions surrounding the trait-related SNP loci. Furthermore, the favorable allelic variation, the "TT" genotype in the SNP loci, was discovered, and a derived cleaved amplified polymorphism (dCAPS) marker was designed that cosegregated with TBF, which could be used for marker-assisted selection (MAS) breeding in C. sinensis. The results obtained from this study can provide a theoretical and applied basis for the MAS of early breeding in tea plants in the future.

An efficient identification strategy of clonal tea cultivars using long-core motif SSR markers.

Microsatellites, or simple sequence repeats (SSRs), especially those with long-core motifs (tri-, tetra-, penta-, and hexa-nucleotide) represent an excellent tool for DNA fingerprinting. SSRs with long-core motifs are preferred since neighbor alleles are more easily separated and identified from each other, which render the interpretation of electropherograms and the true alleles more reliable. In the present work, with the purpose of characterizing a set of core SSR markers with long-core motifs for well fingerprinting clonal cultivars of tea (Camellia sinensis), we analyzed 66 elite clonal tea cultivars in China with 33 initially-chosen long-core motif SSR markers covering all the 15 linkage groups of tea plant genome. A set of 6 SSR markers were conclusively selected as core SSR markers after further selection. The polymorphic information content (PIC) of the core SSR markers was >0.5, with ≤5 alleles in each marker containing 10 or fewer genotypes. Phylogenetic analysis revealed that the core SSR markers were not strongly correlated with the trait 'cultivar processing-property'. The combined probability of identity (PID) between two random cultivars for the whole set of 6 SSR markers was estimated to be 2.22 × 10(-5), which was quite low, confirmed the usefulness of the proposed SSR markers for fingerprinting analyses in Camellia sinensis. Moreover, for the sake of quickly discriminating the clonal tea cultivars, a cultivar identification diagram (CID) was subsequently established using these core markers, which fully reflected the identification process and provided the immediate information about which SSR markers were needed to identify a cultivar chosen among the tested ones. The results suggested that long-core motif SSR markers used in the investigation contributed to the accurate and efficient identification of the clonal tea cultivars and enabled the protection of intellectual property.

[Classics textual research and using situation investigation of Tibetan medicine "Zha-xun"].

In this article the classics textual research to the origin of "Zha-xun" was carried out, the ethnobotanical research methods, the origin of visits, key informant interviews, sample collection and textual research were applied in the research. The results showed that the hypothesis of Zha-xun"s origin mainly included "source of mine", "source of feces", "source of monkey menstrual blood" in China. There were "source of fossil", "source of the plant secretion" abroad. The authors had interviewed the villagers at origin, herbalists, Tibetan doctors, herb dealers, foreign scholars for a total of 18 people, and collecting 45 batches medicinal materials. According to ancient Tibetan classics textual and Tibetan medicine doctors' views, medicinal materials were divided into the genuine and the substitutes. The genuine was identified as ancient so-called "iron" type "Zha-xun", and the substitute was fecal pellet bonding briquette. According to the field survey and literature research, "source of fossil" more in line with substance of Zha-xun was derived from the rock. As the results, the author believed that Zha-xun was the mixture of organic fossils from the rock seepage with flying squirrel, pika feces. So it is needed to be set up Zha-xun classification standard to evaluate the quality of medicinal materials. Meanwhile, it was necessary to further clarify fecal pellet substitute rationality. Above all, this article clarified the status of the use of Tibetan medicine-"Zha-xun", and laid the foundation of species systematics and quality standards research of "Zha-xun".