水稻杂种一代与亲本幼苗基因表达差异的分析

杂种优势是一种普遍存在的生物学现象,其形成的原因十分复杂。本世纪初,Bruce和Shull相继提出的杂种优势形成的显性互补假设和超亲优势假设至今仍作为一种理论模型而缺乏实验证实。水稻杂种优势的利用自70年代三系配套技术建立得到了广泛的应用,但水稻杂种优势形成的遗传学基础目前还知之甚少。在水稻杂种优势形成机理研究中,分别从生理生化代谢、同工酶分析、DNA限制性片段多态性和DNA含量差异进行了分析,但杂种优势形成的分子机理仍未得到阐明。杂种优势的形成是与异质化相关的过程,它涉及到两个遗传背景不同的体系的相互作用。因此,在相互作用过程中,亲本基因的表达与调控就决定了杂种一代的基因表达类型和特性。因此,我们从分析基因表达与调控入手,运用mRNA差异展示技术分析了玉米杂种一代与亲本基因表达的差异,揭示了不少有意义的现象。本研究以水稻籼型杂交组合(汕优63:珍汕97A×明恢63)为材料,探讨水稻杂种一代与亲本基因表达的差异,揭示了杂种优势形成过程中的一些重要现象。

ALTERATION OF GENE EXPRESSION IN RICE HYBRID F_1 AND ITS PARENTAL SEEDLINGS

Hybrid rice (Oryza sativa L.) seedling is more vigorous in root development and plant growth than its parental lines in the tested indica rice of hybridized combination (Shanyou 63 ( F1): Zhenshan 97 A Minghui 63). Analysis of the difference in gene expression between the hybrid F1 and its parental seedlings by means of mRNA differential display indicated that gene expression of the parental lines was obviously altered the hybrid F1 both in quantity and quality. Quantitatively, there were over-expression and under-expression of genes in hybrid F1 with genetic expression trend forwards a single parent. Quantitatively, hybrid F1 could have specific gene expression, single parent (maternal or paternal) gene silence, co-suppression of paternal genes, and single paternal gene expression. The relationship between heterosis formation and alteration of gene expression of parental lines in hybrid F1 was also discussed.