In this study, we used plant material from Juglandaceae to develop a new nuclear DNA marker within the ubiquitin ligase gene (UBE3) region to discriminate the representative samples (species/variety/cultivars) of the genus Juglans. Our objectives were: (i) to test the applicability of the nuclear DNA marker from the UBE3 gene region; and (ii) to evaluate the resolution ability of the nuclear DNA marker from the UBE3 gene region. The results of this effort show that UBE3 is sensitive for characterizing genetic diversity in the family

Juglandaceae. Nine representative taxa of the genus Juglans and two outgroups (Cyclocarya paliurus and Pterocarya stenoptera in Juglandaceae) were used in this study ( Table 1). The eleven taxa were sampled from three places: the resources nursery click here (N 34°18′, E 111°30′) of Forestry Bureau of Anti-diabetic Compound Library Luoning County, Henan Province, China; the Arboretum (N 25°08′, E 102°45′) of Forestry Academy of Yunnan Province, located at Heilongtan in the northern suburbs

of Kunming City, Yunnan, China; and Beijing Botanical Garden (N 39°48′, 116°28′) under the Institute of Botany, Chinese Academy of Sciences, Beijing, China. All necessary permits for the collection of fresh leaves from the trees growing at each place were acquired prior to material collection. All collected material was verified by a taxonomic expert. Fresh leaves of each accession were collected in the spring and dried immediately using silica gel for future DNA extraction. Total genomic DNA was extracted using the Plant Genomic DNA Kit (DP305) from Tiangen Biotech (Beijing) Co., Ltd. China. The nuclear DNA BCKDHA UBE3 gene locus was amplified using the primer pair H_UBE3_23f (5′-TCGCCTCCAAGTTCAGTG-3′) and H_UBE3_838r (5′-CTCCCATAGGTGTAGTTCCA-3′). Taq DNA polymerase and PCR buffer (TaKaRa Code: DR100B) were from TaKaRa Biotechnology Co., Ltd. (Dalian, China). The PCR protocol were as follows: preheating at 94 °C for 4 min, 34 cycles at 94 °C for

45 s, annealing at 52 °C for 45 s and elongation at 72 °C for 1.2 min, followed by a final extension at 72 °C for 10 min. PCR amplification of the regions of interest was performed in an Applied Biosystems VeritiTM 96-Well Thermal Cycler (Model#: 9902, made in Singapore). The amplicons were resolved simultaneously on 2% agarose gels (Promega, the USA) run in 1 × TAE buffer at 3 V cm−1 for 2.5 h and were stained with ethidium bromide. The fragments (PCR products) were directly sequenced with the same primer pair mentioned above using a 3730xl DNA analyzer (Applied Biosystems, Foster City, CA, USA). The DNA sequences were aligned with ClustalX [15] and then were manually confirmed using Sequencher (v4.6) software. Sequence haplotype diversity was calculated using DnaSP (DNA Sequences Polymorphism version 5.10.01) software [16]. Sequence datasets were analyzed using Mega 6 software [17].