Characterization of the wheat gene encoding a grain-specific lipid transfer protein TdPR61, and promoter activity in wheat, barley and rice.
The TaPR61 gene from bread wheat encodes a lipid transfer protein (LTP) with a hydrophobic signal peptide, predicted to direct the TaPR61 protein to the apoplast. Modelling of TaPR61 revealed the presence of an internal cavity which can accommodate at least two lipid molecules. The full-length gene, including the promoter sequence of a TaPR61 orthologue, was cloned from a BAC library of Triticum durum. Quantitative RT-PCR analysis revealed the presence of TaPR61 and TdPR61 mainly in grain. A transcriptional TdPR61 promoter-GUS fusion was stably transformed into wheat, barley, and rice. The strongest GUS expression in all three plants was found in the endosperm transfer cells, the embryo surrounding region (ESR), and in the embryo. The promoter is strong and has similar but not identical spatial patterns of activity in wheat, barley, and rice. These results suggest that the TdPR61 promoter will be a useful tool for improving grain quality by manipulating the quality and quantity of nutrient/lipid uptake to the endosperm and embryo. Mapping of regions important for the promoter function using transient expression assays in developing embryos resulted in the identification of two segments important for promoter activation in embryos. The putative cis-elements from the distal segment were used as bait in a yeast 1-hybrid (Y1H) screen of a cDNA library prepared from the liquid part of the wheat multinucleate syncytium. A transcription factor isolated in the screen is similar to BES1/BLZ1 from Arabidopsis, which is known to be a key transcriptional regulator of the brassinosteroid signalling pathway.
Australian Centre for Plant Functional Genomics, University of Adelaide, South Australia, Australia.
Nataliya
N
Kovalchuk
Jessica
J
Smith
Natalia
N
Bazanova
Tatiana
T
Pyvovarenko
Rohan
R
Singh
Neil
N
Shirley
Ainur
A
Ismagul
Alexander
A
Johnson
Andrew S
AS
Milligan
Maria
M
Hrmova
Peter
P
Langridge
Sergiy
S
Lopato
D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D002523:Edible Grain / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D015723:Gene Library; D001467:Hordeum / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D012275:Oryza / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics*; D016415:Sequence Alignment; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; D018076:DNA, Complementary; D010940:Plant Proteins; D014157:Transcription Factors; C030363:lipid transfer protein