title: The 160 bp Insertion in the Promoter of Rht-B1i Plays a Vital Role in Increasing Wheat Height.
abstract: The extensive use of two alleles (Rht-B1b and Rht-D1b) at the Rht-1 locus in wheat allowed dramatic increases in yields, triggering the so-called "Green Revolution." Here, we found that a new natural allelic variation (Rht-B1i) containing a single missense SNP (A614G) in the coding region significantly increased plant height against the genetic background of both Rht-D1a (11.68%) and Rht-D1b (7.89%). To elucidate the molecular mechanism of Rht-B1i, we investigated the promoter region. Sequence analysis showed that the Rht-B1i promoter could be divided into two classes depending on the presence or absence of a specific 160 bp insertion: Rht-B1i-1 (with the 160 bp insertion) and Rht-B1i-2 (without the 160 bp insertion). The promoter of Rht-B1i-1 contained 32 more possible cis-acting elements than Rht-B1a, including a unique auxin response element AUXREPSIAA4. Quantitative RT-PCR analysis indicated that the 160 bp insertion is likely to promote the transcription of the Rht-B1i-1 gene. The coleoptile lengths of wheat varieties treated with IAA, GA3, and IAA/GA3, combined with the histochemical staining of transgenic Arabidopsis containing the Rht-B1i-1 promoter, showed that the height-increasing effect of Rht-B1i-1 may be due to the synergistic action of IAA and GA3. These results augment our understanding of the regulatory mechanisms of Rht-1 in wheat and provide new genetic resources for wheat improvement.
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China; Graduate University of Chinese Academy of SciencesBeijing, China.
authors.forename: Xueyuan
authors.initials: X
authors.lastname: Lou
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China; Graduate University of Chinese Academy of SciencesBeijing, China.
authors.forename: Aixia
authors.initials: A
authors.lastname: Li
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China; Graduate University of Chinese Academy of SciencesBeijing, China.
authors.forename: Mingyu
authors.initials: M
authors.lastname: Pu
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences Beijing, China.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Shoaib
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences Beijing, China.
authors.forename: Dongcheng
authors.initials: D
authors.lastname: Liu
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences Beijing, China.
authors.forename: Jiazhu
authors.initials: J
authors.lastname: Sun
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of SciencesBeijing, China; The Collaborative Innovation Center for Grain Crops in Henan, Henan Agricultural UniversityZhengzhou, China.
authors.forename: Aimin
authors.initials: A
authors.lastname: Zhang
authors.affiliation: The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences Beijing, China.
authors.forename: Wenlong
authors.initials: W
authors.lastname: Yang
keywords: 160 bp insertion; Rht-B1i; Triticum aestivum L.; height-increasing effect; promoter