Characterization and functional analysis of maize df in a new mutant allele
Lingfeng Ye, Anqi Xing, Lin Liu, Jiansheng Li and Dingming Kang* 

College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193.
* Corresponding Author：kdm@pku.edu.cn

Abstract
Dwarfism is one of important traits in establishment  of crop ideotype，especially for Gramineous crops. Up to now, more than 40 monogenic dwarfing mutants have been described in maize. Df, which displays a typical shorter height in maize growth, has been demonstrated from a dysfunctional auxin polar transporter. DF has two orthologue in Arabidopsis thaliana designated PGP1 and PGP19, have been reported. We have screened a new allele of df, which was shown a somewhat quantity characteristic functional in  regulation of maize height.  We mapped df locus of  the new mutant and identified the semi-dwarf phenotype, narrow leaf angle and enhanced stalk internodes, which make it potential in future maize breeding.  To further understand its molecular mechanism and functional pathway as an auxin transporter, we complemented it in  Arabidopsis pgp1 and pgp19 mutants to analyze  the dwarf phenotypes with 35S promoter. Additionally, the temporal and spatial expression pattern with Pro_Df::GUS construct, the subcellular co-localization of DF and IAA transport assay were exhibited the  molecular mechanism of DF in auxin signalling of  maize height development.

Key words: Dwarfism, Auxin polar transport, Maize, Arabidopsis