Delineating the structural, functional and evolutionary relationships of sucrose phosphate synthase gene family II in wheat and related grasses.
BACKGROUND
Sucrose phosphate synthase (SPS) is an important component of the plant sucrose biosynthesis pathway. In the monocotyledonous Poaceae, five SPS genes have been identified. Here we present a detailed analysis of the wheat SPSII family in wheat. A set of homoeologue-specific primers was developed in order to permit both the detection of sequence variation, and the dissection of the individual contribution of each homoeologue to the global expression of SPSII.


RESULTS
The expression in bread wheat over the course of development of various sucrose biosynthesis genes monitored on an Affymetrix array showed that the SPS genes were regulated over time and space. SPSII homoeologue-specific assays were used to show that the three homoeologues contributed differentially to the global expression of SPSII. Genetic mapping placed the set of homoeoloci on the short arms of the homoeologous group 3 chromosomes. A resequencing of the A and B genome copies allowed the detection of four haplotypes at each locus. The 3B copy includes an unspliced intron. A comparison of the sequences of the wheat SPSII orthologues present in the diploid progenitors einkorn, goatgrass and Triticum speltoides, as well as in the more distantly related species barley, rice, sorghum and purple false brome demonstrated that intronic sequence was less well conserved than exonic. Comparative sequence and phylogenetic analysis of SPSII gene showed that false purple brome was more similar to Triticeae than to rice. Wheat - rice synteny was found to be perturbed at the SPS region.


CONCLUSIONS
The homoeologue-specific assays will be suitable to derive associations between SPS functionality and key phenotypic traits. The amplicon sequences derived from the homoeologue-specific primers are informative regarding the evolution of SPSII in a polyploid context.
Sharma
Shailendra
S
Leibniz Institute of Plant Genetics and Crop Plant Research, Gatersleben, Germany. shail6_r@rediffmail.com
Sreenivasulu
Nese
N
Harshavardhan
Vokkaliga Thammegowda
VT
Seiler
Christiane
C
Sharma
Shiveta
S
Khalil
Zaynali Nezhad
ZN
Akhunov
Eduard
E
Sehgal
Sunish Kumar
SK
Röder
Marion S
MS
D001483:Base Sequence; D002874:Chromosome Mapping; D018506:Gene Expression Regulation, Plant; D023061:Gene Order; D014644:Genetic Variation; D018745:Genome, Plant / Q000235:genetics; D005964:Glucosyltransferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D007438:Introns / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D006109:Poaceae / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D014908:Triticum / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000254:growth & development
D005964:Glucosyltransferases; C022698:sucrose-phosphate synthase