Original Paper

Theoretical and Applied Genetics

, Volume 126, Issue 5, pp 1321-1336

First online:

Genetic characterization and mapping of the Rht-1 homoeologs and flanking sequences in wheat

  • Edward P. WilhelmAffiliated withNational Institute of Agricultural BotanyJohn Innes Centre Email author 
  • , Rhian M. HowellsAffiliated withNational Institute of Agricultural Botany
  • , Nadia Al-KaffAffiliated withJohn Innes CentreTaibah University
  • , Jizeng JiaAffiliated withKey Laboratory of Crop Germplasm Resources and Utilization, Ministry of Agriculture, National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences
  • , Catherine BakerAffiliated withJohn Innes Centre
  • , Michelle A. Leverington-WaiteAffiliated withJohn Innes Centre
  • , Simon GriffithsAffiliated withJohn Innes Centre
  • , Andy J. GreenlandAffiliated withNational Institute of Agricultural Botany
  • , Margaret I. BoultonAffiliated withJohn Innes Centre
    • , Wayne PowellAffiliated withNational Institute of Agricultural BotanyInstitute of Biological, Environmental, and Rural Sciences

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Abstract

The introgression of Reduced height (Rht)-B1b and Rht-D1b into bread wheat (Triticum aestivum) varieties beginning in the 1960s led to improved lodging resistance and yield, providing a major contribution to the ‘green revolution’. Although wheat Rht-1 and surrounding sequence is available, the genetic composition of this region has not been examined in a homoeologous series. To determine this, three Rht-1-containing bacterial artificial chromosome (BAC) sequences derived from the A, B, and D genomes of the bread wheat variety Chinese Spring (CS) were fully assembled and analyzed. This revealed that Rht-1 and two upstream genes were highly conserved among the homoeologs. In contrast, transposable elements (TEs) were not conserved among homoeologs with the exception of intronic miniature inverted-repeat TEs (MITEs). In relation to the Triticum urartu ancestral line, CS-A genic sequences were highly conserved and several colinear TEs were present. Comparative analysis of the CS wheat BAC sequences with assembled Poaceae genomes showed gene synteny and amino acid sequences were well preserved. Further 5′ and 3′ of the wheat BAC sequences, a high degree of gene colinearity is present among the assembled Poaceae genomes. In the 20 kb of sequence flanking Rht-1, five conserved non-coding sequences (CNSs) were present among the CS wheat homoeologs and among all the Poaceae members examined. Rht-A1 was mapped to the long arm of chromosome 4 and three closely flanking genetic markers were identified. The tools developed herein will enable detailed studies of Rht-1 and linked genes that affect abiotic and biotic stress response in wheat.