Loss-of-function of DELLA protein SLN1 activates GA signaling in barley aleurone

Gibberellic acid (GA) is an important signaling molecule that participates in many aspects of plant growth and development. While the importance of this hormone is clear, the transcriptional regulatory networks involved are still being characterized. The cereal aleurone, particularly the barley aleurone, has been used as a classic model to study GA and GA signaling for many years, and these studies have significantly contributed to our understanding of GA in plant biology. The objective of this study was to characterize the transcripts regulated through the DELLA protein SLN1, a negative regulator of the GA signaling pathway. To detect the transcripts, Affymetrix Barley 1 GeneChips were hybridized with RNA extracted from barley aleurone treated with GA or aleurone of the DELLA mutant sln1c without GA treatment. The transcripts detected, in term of both expressed genes and their function, were highly similar between the GA-treatment and the sln1c mutant. These results from a genome-wide transcript analysis provide evidence that SLN1 in the GA signal transduction pathway controls almost all GA-induced genes in the barley aleurone.