MULTIGENE FAMILIES ARE DIFFERENTIALLY EXPRESSED BETWEEN WHEAT HYBRIDS AND THEIR PARENTAL INBREDS IN PRIMARY ROOTS AND SEEDLING LEAVES

Department of Plant Genetics & Breeding China Agricultural University Beijing 100094,P.R.China

In order to identify the gene families possibly associated with wheat heterosis and to understand the mechanism of their regulation in manifestation of wheat heterosis, modified differential display of mRNA was used to analyze the expression patterns of multigene families between wheat hybrids and their parental lines. By using specific primers of MADS-box, GBFs and Ser/Thr protein kinase gene families, we found that significant differences in gene expression patterns of the three multigene families existed between wheat hybrid and their parental inbreds in both primary roots and seedling leaves. Both quantitative and qualitative differences were observed, but the major difference (over 70%) occurred in qualitative level, which is obviously different from the result of our previous study using random primers (Euphytica,106:117-123,1999), where major difference in quantitative level were observed. Further analysis demonstrated that hybrid-specific expressed and inhibited types are the main patterns of differential gene expression. It had been shown that the proteins encoded by the genes of MADS-box or GBFs family belonged to transcription factors, activities of most transcription factors were regulated by protein kinase, especially Ser/Thr protein kinase. Therefore, we speculate that the three types of regulatory protein may play important roles in wheat heterosis, further studies should be to isolate differentially expressed regulatory protein genes, and study their function and their relation to heterosis.