Sequencing Reveals Sex-Specific Markers In Kiwifruit Genome

AsianScientist (Oct. 28, 2015) – Scientists from Wuhan Botanical Garden have sequenced the genome of kiwifruits from inter-species breeding. Their results, presented the genetic maps, have been published in DNA Research. Kiwifruit (Actinidia chinensis Planchon), one of the most recently domesticated specialty fruit crops, is currently grown commercially worldwide. The genus Actinidia, with 58 chromosomes, is comprised of 54 species and 75 taxa in total. Most of these species occur naturally in China. As most commercial cultivars were developed from a narrow pool of A. chinensis germplasm, they suffer from a narrow genetic diversity. Unfortunately, limited genetic and genomic information has hampered attempts at cultivar improvement. In the present study, a team of researchers led by Professor Huang Hongwen has generated high-density kiwifruit genetic maps using an interspecific F1 cross between Actinidia rufa ‘MT570001’ and A. chinensis ‘Guihai No4.’ The A. rufa (maternal) map contained 2,426 single-nucleotide polymorphism (SNP) markers with 29 linkage groups (LGs) spanning over 2,651 cM, while, the A. chinensis (paternal) map with 4,214 SNP markers in 29 LGs spanning 3,142 cM. Collinearity between the A. rufa and A. chinensis genetic maps. Credit: Zhang Qiong/CAS. Using these maps, 440 unmapped scaffolds from the kiwifruit reference genome were anchored to chromosomes. The high-density genetic maps are beneficial for kiwifruit breeding programmes and improving the kiwifruit draft genome assembly. As a functionally dioecious plant with male and female reproductive structures on separate plants, kiwifruits present unique challenges for breeding and production. The authors have identified three sex-specific simple sequence repeats (SSR) markers that can accurately distinguish males and females. This information is useful in kiwifruit breeding and commercial production for marker-assisted selection for sex. By locating the three SSR markers in 1-2 Mb on chromosome 25, the sex determination region (SDR) in kiwifruit was narrowed to a 1 Mb region. The article can be found at: Zhang et al. (2015) High-Density Interspecific Genetic Maps of Kiwifruit and the Identification of Sex-Specific Markers. ——— Source: Chinese Academy of Sciences; Photo: Christian Schnettelker/Flickr/CC. Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff. Read more from Asian Scientist Magazine at: http://www.asianscientist.com/2015/10/in-the-lab/cas-whole-genome-sequence-kiwifruits/