Brasileiro-Vidal A C, Dos Santos-Serejo J A, Soares Filho W Dos S, Guerra M
Departamento de Botânica, Centro de Ciências Biológicas, Universidade Federal de Pernambuco, Rua Nelson Chaves s/n. Cidade Universitária, Recife, PE, Brazil.
Genetica. 2007 Mar;129(3):273-9. doi: 10.1007/s10709-006-0007-4. Epub 2006 Aug 4.
Several chromosome types have been recognized in Citrus and related genera by chromomycin A(3 )(CMA) banding patterns and fluorescent in situ hybridization (FISH). They can be used to characterize cultivars and species or as markers in hybridization and backcrossing experiments. In the present work, characterization of six cultivars of P. trifoliata ("Barnes", "Fawcett", "Flying Dragon", "Pomeroy", "Rubidoux", "USDA") and one P. trifoliata x C. limonia hybrid was performed by sequential analyses of CMA banding and FISH using 5S and 45S rDNA as probes. All six cultivars showed a similar CMA(+) banding pattern with the karyotype formula 4B + 8D + 6F. The capital letters indicate chromosomal types: B, a chromosome with one telomeric and one proximal band; D, with only one telomeric band; F, without bands. In situ hybridization labeling was also similar among cultivars. Three chromosome pairs displayed a closely linked set of 5S and 45S rDNA sites, two of them co-located with the proximal band of the B type chromosomes (B/5S-45S) and the third one co-located with the terminal band of a D pair (D/5S-45S). The B/5S-45S chromosome has never been found in any citrus accessions investigated so far. Therefore, this B chromosome can be used as a marker to recognize the intergeneric Poncirus x Citrus hybrids. The intergeneric hybrid analyzed here displayed the karyotype formula 4B + 8D + 6F, with two chromosome types B/5S-45S and two D/5S-45S. The karyotype formula and the presence of two B/5S-45S chromosomes clearly indicate that the plant investigated is a symmetric hybrid. It also demonstrates the suitability of karyotype analyses to differentiate zygotic embryos or somatic cell fusions involving trifoliate orange germplasm.
通过放线菌素A（3）（CMA）带型分析和荧光原位杂交（FISH），在柑橘属及相关属中已识别出几种染色体类型。它们可用于鉴定品种和物种，或作为杂交和回交实验中的标记。在本研究中，利用5S和45S rDNA作为探针，通过CMA带型分析和FISH的顺序分析，对6个枳（“巴恩斯”、“福西特”、“飞龙”、“波默罗伊”、“鲁比杜克斯”、“美国农业部”）品种和1个枳×酸橙属间杂种进行了鉴定。所有6个品种均显示出相似的CMA（+）带型模式，核型公式为4B + 8D + 6F。大写字母表示染色体类型：B，一条具有一个端粒带和一个近端带的染色体；D，只有一个端粒带；F，无带。品种间的原位杂交标记也相似。三对染色体显示出一组紧密相连的5S和45S rDNA位点，其中两对与B型染色体的近端带共定位（B/5S - 45S），第三对与一对D染色体的末端带共定位（D/5S - 45S）。到目前为止，在任何已研究的柑橘种质中都从未发现过B/5S - 45S染色体。因此，这条B染色体可作为识别枳属×柑橘属间杂种的标记。这里分析的属间杂种显示核型公式为4B + 8D + 6F，有两种染色体类型B/5S - 45S和两种D/5S - 45S。核型公式以及两条B/5S - 45S染色体的存在清楚地表明所研究的植物是一个对称杂种。这也证明了核型分析适用于区分涉及枳橙种质的合子胚或体细胞融合。
