Wolters A A, Vergunst A C, van der Werff F, Koornneef M
Department of Genetics, Wageningen Agricultural University, The Netherlands.
Mol Gen Genet. 1993 Dec;241(5-6):707-18. doi: 10.1007/BF00279915.
Protoplast fusion experiments between Lycopersicon esculentum or L. peruvianum and Nicotiana tabacum or N. plumbaginifolia were performed to investigate the possibility of producing symmetric and asymmetric somatic hybrids between these genera. These fusions, which involved 1.7 x 10(8) protoplasts, yielded 35 viable hybrid calli. Plant regeneration was successful with two calli. One of these regenerants flowered, but developed no fruits. Analysis of the nuclear DNA by means of dot blot hybridization with species-specific repetitive DNA probes combined with flow cytometry, revealed that the nuclei of most hybrid calli contained the same absolute amount of Nicotiana DNA as the Nicotiana parent or (much) less, whereas the amount of Lycopersicon DNA per nucleus was 2-5 times that of the parental genotype. Eighteen of the 34 hybrids analyzed possessed Lycopersicon chloroplast DNA (cpDNA), whereas the other 16 had DNA from Nicotiana chloroplasts. The cpDNA type was correlated with the nuclear DNA composition; hybrids with more than 2C Nicotiana nuclear DNA possessed Nicotiana chloroplasts, whereas hybrids with 2C or less Nicotiana nuclear DNA contained Lycopersicon chloroplasts. Mitochondrial DNA (mtDNA) composition was correlated with both nuclear DNA constitution and chloroplast type. Hybrids possessed only or mainly species-specific mtDNA fragments from the parent predominating in the nucleus and often providing the chloroplasts. The data are discussed in relation to somatic incompatibility which could explain the low frequency at which hybrids between Lycopersicon and Nicotiana species are obtained and the limited morphogenetic potential of such hybrids.
开展了番茄（Lycopersicon esculentum）或秘鲁番茄（L. peruvianum）与烟草（Nicotiana tabacum）或垂花烟草（N. plumbaginifolia）之间的原生质体融合实验，以研究在这些属间产生对称和不对称体细胞杂种的可能性。这些融合涉及1.7×10⁸个原生质体，产生了35个可存活的杂种愈伤组织。两个愈伤组织成功再生出植株。其中一个再生植株开花，但未结果。通过与物种特异性重复DNA探针进行斑点杂交并结合流式细胞术对核DNA进行分析，结果显示，大多数杂种愈伤组织的细胞核所含烟草DNA的绝对量与烟草亲本相同或（远）低于烟草亲本，而每个细胞核中番茄DNA的量是亲本基因型的2至5倍。在分析的34个杂种中，18个具有番茄叶绿体DNA（cpDNA），而另外16个具有来自烟草叶绿体的DNA。cpDNA类型与核DNA组成相关；具有超过2C烟草核DNA的杂种具有烟草叶绿体，而具有2C或更少烟草核DNA的杂种含有番茄叶绿体。线粒体DNA（mtDNA）组成与核DNA构成和叶绿体类型均相关。杂种仅具有或主要具有来自在细胞核中占主导且通常提供叶绿体的亲本的物种特异性mtDNA片段。结合体细胞不亲和性对这些数据进行了讨论，体细胞不亲和性可以解释为何番茄和烟草物种间杂种的获得频率较低以及此类杂种的形态发生潜力有限。
