Haplotype dictionary for the Rht-1 loci in wheat

Abstract

The introduction of Reduced height (Rht)-B1b and Rht-D1b into bread wheat (Triticum aestivum) varieties was a key component of the 'green revolution' and today these alleles are the primary sources of semi-dwarfism in wheat. The Rht-1 loci encode DELLA proteins, which are transcription factors that affect plant growth and stress tolerance. In bread wheat, Rht-D1b and Rht-B1b influence resistance to the disease Fusarium Head Blight. To identify Rht-1 variants, locus specific primers were developed and used to sequence the entire open reading frame (ORF) and 1.7 kb of the 5' and 0.5 kb of the 3' flanking regions of Rht-A1 (Rht-A1+f), Rht-B1 (Rht-B1+f), and Rht-D1 (Rht-D1+f) in bread wheat (36 sequences from each genome) and tetraploid and diploid wheat (TDW) (one to three sequences from each genome). Among the bread wheat accessions, the Rht-A1+f and Rht-D1+f sequences contained relatively low genetic diversity and few haplotypes relative to the Rht-B1+f sequences. The TDW accessions were relatively rich in genetic diversity and contained the majority of the polymorphic sites. Novel polymorphisms, relative to 'Chinese Spring', discovered among the accessions include 160 and 197 bp insertions 5' of Rht-B1 and a frameshift in the Rht-B1 ORF. Quantitative real-time PCR using shoot and leaf tissue from 5-day-old seedlings of genotypes lacking or containing the 5' insertions revealed no major effect on Rht-B1 transcript accumulation. This research provides insights into the genetic diversity present at the Rht-1 loci in modern bread wheat and in relation to ancestral wheat accessions.

Ppd1, Vrn1, ALMT1 and Rht genes and their effects on grain yield in lower rainfall environments in southern Australia

“…Wilhelm et al (2013) were identified using the multiplex PCR method described by those authors. We used 1 pmol/mL of the forward primer Rht-F11 in combination with 0.33 pmol/mL each of reverse primers 160-R1, 197-R1 and Rht-ABD-R9 in 10-mL reaction volumes; initial denaturation was at 958C for 3 min followed by amplification with Bioline MyTaqÔ Red DNA polymerase over 32 cycles of 958C for 30 s, 608C for 30 s and 728C for 90 s, where necessary reactions were held at 128C before electrophoresis through 1.5% TAE-agarose gels (Wilhelm et al 2013).…”

“…Chinese Spring, but six lines in the dataset we analysed carried the allele with a 197-bp insertion that Wilhelm et al (2013) found in cv. Cappelle Desprez.…”

“…The Rht-D1b allele was introduced from MEC3 (pedigree: Sonora 64//Tezanos Pintos Precoz/Yaqui 54) into cultivars related to Spear and Dagger, or from Pavon F 76 (Eagles et al 2009). There are other, less important sources of both Rht-ba and Rht-ab (Gale and King 1988), but the gibberellin-insensitive Rht-B1b and Rht-D1b alleles in all Australian cultivars trace back to the (Wilhelm et al 2013), which we will consider again later in this paper. The Rht genes code for DELLA proteins, which are transcription factors that affect plant growth and stress tolerance (Wilhelm et al 2013).…”

“…There are other, less important sources of both Rht-ba and Rht-ab (Gale and King 1988), but the gibberellin-insensitive Rht-B1b and Rht-D1b alleles in all Australian cultivars trace back to the (Wilhelm et al 2013), which we will consider again later in this paper. The Rht genes code for DELLA proteins, which are transcription factors that affect plant growth and stress tolerance (Wilhelm et al 2013). In southern Australia, the difference between the Rht-ba and Rht-ab semi-dwarf genotypes with respect to heading date is negligible (Fischer and Quail 1990;Cane et al 2013), which was also the case in Germany and the USA (Börner et al 1993;Butler et al 2005).…”

“…The semi-dwarf stature considered in this paper is determined by the Rht-B1 and Rht-D1 genes on chromosomes 4BS and 4DS (Ellis et al 2002;Wilhelm et al 2013). The gibberellininsensitive Rht-B1b allele and largely photoperiod-insensitive Ppd-D1a allele were principally introduced into Australian wheat breeding from 'WW15', a line Pugsley (1983) considered to be 'the most significant wheat introduced to Australia this century'.…”