Development and utilization of genomic and genic microsatellite markers in Assam tea (Camellia assamica ssp assamica) and related Camellia species

作者：Bhardwaj Pankaj; Kumar Rahul; Sharma Himanshu; Tewari Rupinder; Ahuja Paramvir S; Sharma Ram K^*

来源：Plant Breeding, 2013, 132(6): 748-763.

DOI：10.1111/pbr.12101

• Camellia assamica
• heterozygosity
• genetic diversity
• microsatellite markers

Microsatellite or simple sequence repeat (SSR) markers are valuable tools for many purposes, such as phylogenetic, fingerprinting and molecular breeding studies. However, such marker resources are unavailable in Assam tea (Camellia assamica ssp. assamica; Masters). With an objective to enrich the repertoire of microsatellite markers in traditional tea, 185 novel microsatellite (150 genomic and 35 genic) markers were identified from (GA)n-enriched genomic libraries and public expressed sequence data in Assam tea. High-quality 0.412-Mb non-redundant (NR) genomic data set derived from nucleotide sequencing of 1297 (GA)n-enriched genomic positive clones and 2723 unigenes (1.33Mb) predicted from 10803 random public expressed sequence tags (ESTs) in C.assamica ssp. assamica were utilized for identification of genomic and genic microsatellite markers, respectively. The average number of alleles and polymorphic information content (PIC) recorded for the newly developed SSR markers were 6.17 and 0.398, respectively. The average observed (H-o) and expected (H-e) heterozygosity varied from 0.626 to 0.697, respectively. These markers were found to be highly transferable (74.5-100%) to cultivated (C.sinensis, C.assamica ssp. lasiocalyx) and five wild Camellia species. Genetic diversity coefficient detected a high level of divergence in 24 cultivated tea accessions (69.3%). Phylogenetic analysis revealed that major groupings were broadly in accordance with taxonomic classification of tea, and all the wild Camellia species remained as an out-group. The high polymorphic content coupled with high rate of cross-transferability demonstrates wider applicability of novel microsatellite markers in genotyping, genetic diversity, genome mapping and evolutionary studies in various Camellia species.

• 出版日期2013-12