The wheat super domestication gene Q

摘要

The Q gene is largely responsible for the domestication and widespread cultivation of macaroni and bread wheat primarily because it confers the free-threshing character. It also pleiotropically influences many other domestication-related traits such as glume shape and tenacity, rachis fragility, plant height, spike length, and ear emergence time. For nearly a century, scientists have been intrigued by the Q gene and its pleiotropic nature. Here, we provide a summary of early investigations and discoveries regarding Q and its role in floral morphology and domestication, followed by an overview of our work to clone and characterize Q. Fine-mapping, chromosome walking, and DNA sequence analysis of knockout mutants allowed us to verify that Q is a member of the AP2 class of transcription factors. Analysis of transgenic plants confirmed the dosage and pleiotropic effects of Q on characters such as glume shape and tenacity, rachis fragility, and plant height. The Q and q alleles harbor structural differences, and Q is more abundantly transcribed than q. The q allele is the more primitive, and Q arose only once most likely in a tetraploid, which upon hybridization with Aegilops tauschii produced Triticum aestivum, and from those wheats originated the world's macaroni and bread wheat. Future work will focus on the functional analysis of Q and elucidating associated genes and pathways. Unique methods of improving wheat or domesticating new crops may result from further exploitation of Q, one of the most important genes in the rise of modern civilization.