Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/1996
Publication Date: N/A
Interpretive Summary: Pre-harvest sprouting during rainy weather can reduce cereal seed quality. Sprouting damage can be prevented if seeds retain dormancy through maturation and harvest. However, manipulation of seed dormancy and prevention of sprouting damage is difficult because there is little knowledge of the genes that are expressed in dormant seeds. Here we report the identification and sequencing of an oleosin gene from highly dormant seeds of the wild grass, Bromus secalinus. When seeds are hydrated oleosin expression is maintained in dormant, growth-arrested seeds, but declines in germinating seeds. Oleosins are thought to be involved in maintenance of structural integrity of oil bodies within seeds. This is the first oleosin cloned from a wild grass. This new oleosin clone can be used by scientists to examine the function and evolution of oleosins in cereal and grass seeds. A functional role of oleosins in seed dormancy has not been demonstrated, but this clone can be used to examine the possible role of oleosins in dormant seeds.
Technical Abstract: Our primary interest is the role of signal transduction in seed dormancy and in desiccation tolerance. As part of our analysis, we are engaged in sequencing a series of clones identified by differential screening of a cDNA library from embryos of hydrated dormant Bromus secalinus seeds (Goldmark et al., 1992). B. Secalinus, a weedy grass introduced to North America, is particularly useful as a model system because it posesses a high level of embryonic dormancy. We report here that one of these clones expressed in dormant embryos, 2142A, bears considerable sequence homology to a number of oleosins. Clone 2142A is an 871 bp cDNA clone that is evidently complete. It includes a 168-condon open reading frame, conceptual translation of which yields a protein to 16,985 Daltons. Based on analysis of sequence similarities, we believe the gene product of clone 2142A is an ole 16-type, or low Mr oleosin isoform. This represents the first oleosin cloned from a wild grass.