ARS | Publication request: CHARACTERIZATION OF A BARLEY SHRUNKEN ENDOSPERM MUTANT, SEG8

Submitted to: Oat International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: July 30, 1996
Publication Date: N/A

Interpretive Summary: Several mutant barley plants have been identified whose grain does not fill properly. The seeds appear shriveled, and weigh much less than normal barley seeds. We wanted to identify the genes that cause this mutation, because that may provide some clues about how grain filling is regulated. We examined one of these mutants, called seg8, by comparing its genes with those of normal barley. Several differences were found, and further work is underway to determine if any of these are the cause of the shriveled seed. The next step will be to identify the enzymes produced by the mutant gene or genes, and that will provide information on how grain filling is regulated.

Technical Abstract: The barley (Hordeum vulgare L.) mutant, seg8, is a maternal- effect mutant with a shrunken endosperm phenotype. The mutation is a monofactorial recessive. Research was planned to attempt to identify the mutant locus by differential screening. A cDNA library was constructed from developing seed tissue of cv. Klages, the normal counterpart of seg8, and screened against Klages and seg8 cDNA probes. Six candidate clones were identified that were hybridized with Klages, but not seg8, probes. Following secondary screening, one clone was identified as a putative aspartate aminotransferase gene, because of 73-93 percent similarity of the N-terminal amino acid sequence with other plant aspartate aminotransferases. Seg8 and Klages were crossed, and genomic DNA extracted from F2 plants. An RFLP was identified between seg8 and Klages, and 2 of 16 F2 plants showed the seg8 pattern. F3 plants are being grown to compare the shrunken endosperm phenotypes with the RFLP patterns.