Abstract: Differential gene expression between hybrids and their parents is considered to be associated with heterosis. However, the physiological functions and possible contribution to heterosis of these differentially expressed genes are unknown. We have isolated one hybrid-upregulated gene encoding putative wheat ADP-ribosylation factor, designated TaARF. In this study, realtime quantitative RT-PCR analysis indicated that TaARF transcript was preferentially expressed in root, node and crown, and the accumulation of TaARF mRNA in hybrid was more than 1.5 fold higher than that in two parents. In order to understand possible roles of putative wheat ARF gene, TaARF was overexpressed in Arabidopsis, and the transgenic plants were characterized. We shown that ectopic overexpression of TaARF in Arabidopsis leaded to the increased leaf area, increased growth rate and earlier transition to flowering, suggesting that TaARF plays significant roles in growth and development. This study provides the evidence demonstrating that TaARF plays important roles in growth and development and we speculated that the upregulated expression of this gene might contribute to the heterosis observed in wheat root and leaf growth.

Key words: ADP-ribosylation factor, ectopic overexpression, heterosis, wheat, Arabidopsis