Screening of subtractive cDNA library to find out genes involved in hybrid lethality of F₁ hybrid of Nicotiana gossei x N. tabacum

Abstract

Hybrid lethality, a major reproductive isolation, hinders gene exchanges among taxa. Identification of genes involved in this mechanism is important not only for studies on evolution but also for plant improvement. To find out the genes, we have started to screen cDNA library which enriched expressed genes of GTH4, lethal cultured cells of F₁ hybrid of N. gossei x N. tabacum, compared with that of GTH4S, non-lethal cultured cells. Further screening of 2,016 cDNA clones came out new 15 genes which expressed in GTH4 more strongly than GTH4S. However, only three were verified as preferentially expressed genes in GTH4 by semi-quantitative RT-PCR. These included Pre-pro-proteinase inhibitor I (Acc.#, Z12619), Glycine-rich protein precursor (Acc.#, GU177460) and Inhibitor of microbial serine proteinase (Acc.#, X67075). Analysis for functioning of these genes in hybrid lethality is in progress.