Gene expression in a starch synthase IIa mutant of barley: changes in the level of gene transcription and grain composition.
The barley shrunken grain mutant M292 has a novel high-amylose starch phenotype caused by a mutation in the starch synthase IIa gene (SsIIa) located at the starch excess-6 (sex6) locus on chromosome 7H of barley. The loss of SSIIa enzyme activity leads to a decrease in amylopectin synthesis to less than 20% of the levels found in wild-type grains. Detailed composition analysis indicates that the contents of protein, non-starch polysaccharides, lipid, sucrose and hexoses, and fructo-oligosaccharides are increased in mature M292 grain compared to wild type. Using a microarray analysis, we characterize the differences between the transcription profiles of wild-type and mutant barley endosperms at mid-grain fill. The expression changes include genes involved in carbon storage, stress-related genes, and a number of transcripts with unassigned function. The changes in gene expression are discussed in terms of the altered grain composition of the mutant seed.
Clarke
B
B
CSIRO Plant Industry, GPO, Box 1600, Canberra, ACT, 2601, Australia. bryan.clarke@csiro.au
Liang
R
R
Morell
M K
MK
Bird
A R
AR
Jenkins
C L D
CL
Li
Z
Z
D018076:DNA, Complementary; D018744:DNA, Plant; D015870:Gene Expression; D020869:Gene Expression Profiling; D017343:Genes, Plant; D001467:Hordeum / Q000033:anatomy & histology / Q000201:enzymology* / Q000235:genetics; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D012639:Seeds / Q000033:anatomy & histology / Q000737:chemistry* / Q000201:enzymology / Q000235:genetics; D013214:Starch Synthase / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D018076:DNA, Complementary; D018744:DNA, Plant; D013214:Starch Synthase