Masuda Yu, Yamada Tetsuya, Kuboyama Tsutomu, Marubashi Wataru
Laboratory of Plant Chromosome and Gene Stock, Graduate School of Science, Hiroshima University, 1-4-3 Kagamiyama, Higashi-Hiroshima-city, Hiroshima 739-8526, Japan.
Plant Cell Rep. 2007 Sep;26(9):1595-604. doi: 10.1007/s00299-007-0352-5. Epub 2007 Apr 5.
Hybrid lethality is an important problem for cross-breeding; however, its molecular mechanism is not clear. The purpose of the present study was to identify the genes expressed during hybrid lethality in the hybrid cells (Nicotiana suaveolens x N. tabacum). In order to identify these genes, we employed suppression subtractive hybridization (SSH) between RNA isolated from cells expressing lethality (lethal hybrid line; LH line) and cells overcoming lethality fortuitously (a surviving hybrid line; SH line). Four populations of cDNA were created from the time points corresponding to before and during induction, and at and after the point of no return (PNR) during the process of programmed cell death (PCD) that occurs during hybrid lethality. By SSH and following dot-blot macroarray analysis, 99 genes out of 138 isolated clones were identified as hybrid lethality-related (HLR) genes. Quantitative real-time PCR analysis data indicated that ten clones were expressed specifically in LH line cells. The HLR genes in these clones show homology to genes involved in disease resistance, ethylene-induced reactions, phosphorylation, ubiquitination, jasmonic acid-related reactions, calcium signaling and self-incompatibility. These data suggested that at least some parts of the mechanism of hybrid lethality are shared with those of the putative functions of the HLR gene-related pathways.
杂种致死性是杂交育种中的一个重要问题；然而，其分子机制尚不清楚。本研究的目的是鉴定杂种细胞（黄花烟草×烟草）杂种致死过程中表达的基因。为了鉴定这些基因，我们利用抑制性消减杂交（SSH）技术，对来自表达致死性的细胞（致死杂种系；LH系）和偶然克服致死性的细胞（存活杂种系；SH系）的RNA进行分析。在杂种致死过程中发生的程序性细胞死亡（PCD）过程中，从诱导前、诱导期间、不可逆转点（PNR）及之后对应的时间点构建了四个cDNA文库。通过SSH和随后的点杂交宏阵列分析，在138个分离克隆中，有99个基因被鉴定为杂种致死相关（HLR）基因。定量实时PCR分析数据表明，有10个克隆在LH系细胞中特异性表达。这些克隆中的HLR基因与参与抗病性、乙烯诱导反应、磷酸化、泛素化、茉莉酸相关反应、钙信号传导和自交不亲和的基因具有同源性。这些数据表明，杂种致死机制的至少某些部分与HLR基因相关途径的假定功能相同。
