GRAFT-TRANSFORMATION, THE MECHANISM FOR GRAFT-INDUCED GENETIC CHANGES IN HIGHER-PLANTS
GRAFT-TRANSFORMATION, THE MECHANISM FOR GRAFT-INDUCED GENETIC CHANGES IN HIGHER-PLANTS
复制标题
DOI：
10.1007/bf00022565
复制
发表时间：
1991-05-01
期刊：
影响因子：
1.9
通讯作者：
OHTA, Y
中科院分区：
文献类型：
--
作者：
OHTA, Y
在我们以前的一系列试验报告中，包括辣椒的普通嫁接、病毒接种嫁接和DNA处理，我们描述了这些变异体以及对单个变异体的基因分析，以及所获得的嫁接诱导的遗传变化的特征。对砧木茎的显微组织学分析显示，染色质团，染色成蓝绿色，大小和形状各异，从木质化和死亡细胞穿过细胞壁和细胞间隙，染色成浅紫褐色，向维管束方向移动（图1）。本文讨论了染色质从砧木垂死细胞经维管系统穿过嫁接体向接穗生长点转移的机理（图3），以及该过程如何导致快速分裂的接穗花原基的转化（图4）染色质易位的意义可以从以下几个方面来理解：遗传信息永远不会从砧木传递到接穗，除非一个大于功能单位（如基因）的DNA分子从砧木易位，除非DNA分子本身整合到接穗的新细胞核中。换句话说，如果砧木的DNA分子分解成核苷酸，就像蛋白质分子被消化成氨基酸一样，并被接穗简单地用作原料，以自己的DNA链为模板形成新的细胞核，那么遗传信息就不会传递。以及区分园艺嫁接和遗传嫁接的重要性。
In our previous report of a series of experiments involving ordinary grafting, virus-inoculated grafting and DNA treatment in Capsicum annuum L., we described the variants as well as gene analyses of individual variants, together with the characteristics of the graft-induced genetic changes obtained.Microhistological analysis of the stock stems revealed that chromatin masses, stained to greenish blue and in various sizes and shapes, were moving through cell wall and intercellular space from the lignifying and dying cells, stained to lighter purplish brown, towards the vascular bundles (Fig. 1). I discussed the mechanisms of chromatin transfer from the stock dying cells through the vascular system across the graft-union to the growing point(s) of the scion (Fig. 3), and how that process causes transformation in the fast dividing scion flower primordia (Fig. 4).The significance of chromatin translocation can be understood in the following way: Genetic information is never transmitted from the stock to the scion, unless a DNA molecule larger than a functional unit such as a gene translocates from the stock, and unless the DNA molecules per se are integrated into new cell nuclei of the scion. In other words, no transmission of genetic information will take place, if DNA molecules of the stock disintegrated to nucleotides, as when a protein molecule is digested into amino acids, and are utilized by the scion simply as raw material in the formation of new cell nuclei with its own DNA strand as template.Also discussed were the significance of 'mentor methods', and the importance of distinguishing between horticultural graft and genetical graft (Fig. 2).