|Tai, Yin Shan|
Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/30/2005
Publication Date: 1/5/2006
Citation: Zhang, Z., Tai, Y., Simons, K.J., Fellers, J.P., Gill, B.S., Faris, J.D. 2006. Functional analysis of the domestication gene q in wheat [abstract]. Plant and Animal Genome XIV Conference. Abstact No. P828:307.
Technical Abstract: The Q gene confers the free-threshing character of wheat and pleiotropically influences other domestication-related traits. In previous work, we showed that; Q is a member of the APETALA2 (AP2) family of transcription factors, the Q allele is more abundantly transcribed than q, and Q and q alleles differ for a single amino acid at position 329. In this study, we evaluated functional and regulatory aspects of Q using a knockout mutant, relative quantitative-PCR (RQ-PCR), and the yeast two-hybrid system. Seed of the cultivar Bobwhite was subjected to mutagenesis with EMS. One mutant possessed a speltoid spike with non free-threshing seed. This mutant was also taller with longer leaves and seed compared to the wild type. Sequence analysis of the mutant revealed a point mutation within the Q gene coding region, which induced a stop codon at position 138. RQ-PCR analysis indicated the level of Q transcription in the mutant was significantly reduced compared to the wild type. Yeast two-hybrid analysis of Q and q proteins indicated that the isoleucine at position 329 (I329) in the Q protein led to an abundance of homodimer formation, whereas the valine in the q protein limited homodimer formation. Therefore, the reduced level of transcription observed in the mutant and q genotypes may be due to the inability to form homodimers. Taken together, these results indicated that Q affects a wide range of characters and that the level of Q gene expression may depend on a self-regulatory mechanism for which I329 is critical.