Partial Transfer of Citrus genome to Fortunella species using cell engineering techniques.

点击翻译按钮获取中文摘要

Intergeneric somatic hybrids were produced between embryogenic callus-derived protoplasts of round kumquat (Fortunella japonica Swingle) and ‘Morita navel' orange (Citrus sinensis Osbeck) by electrofusion. Among the eight different fusion strains obtained, six showed nomal morphology, whereas the remainings were malformed. All of the regenerated plants were intermediate in leaf morphology and had thick and round leaves which are typical characteristics of polyploids. Ploidy analyses by flow cytometry and chromosome counting in root-tip cells revealed tetraploidy (2n=4x=36) of these plants. Hybridity of the fusion products were confirmed by RAPD and CAPS analyses. Furthermore, analyses of chloroplast(cp) and mitochondrial(mt) DNA by CAPS showed that these somatic hybrids contained cp and mtDNA of round kumquat without recombination in analyzed regions.While, somatic hybrids were produced between embryogenic callus protoplasts of ‘Shogun' mandarin (C.retuculata Blanco, 2n=2x=18) and leaf protoplasts of grapefruit (C.paradisi Macf., 2n=2x=18) by electrofusion. Hybridity of the two regenerated plants was confirmed by leaf characteristics and nuclear genome analysis using RAPD and CAPS. Flow cytometry and root-tip cell count of the two hybrids revealed a chromosome number of 27. These triploid somatic hybrids on transfer to field showed normal morphology and vigorous growth. These somatic hybrids might have derived from fused cells between haploid cell in callus cultures and mesophyll cell, although the mechanism involved in the occurrence of haploid cells from diploid callus cultures of citrus cultivars is still unclear.