Identification of a negative regulator of gibberellin action, HvSPY, in barley

Masumi Robertson, Stephen M. Swain, Peter M. Chandler, Neil E. Olszewski

Research output: Contribution to journalArticlepeer-review

89 Scopus citations


To broaden our understanding of the molecular mechanisms of gibberellin (GA) action, we isolated a spindly clone (HvSPY) from barley cultivar Himalaya and tested whether the HvSPY protein would modulate GA action in barley aleurone. The HvSPY cDNA showed high sequence identity to Arabidopsis SPY along its entire length, and the barley protein functionally complemented the spy-3 mutation. HvSPY and SPY proteins showed sequence relatedness with animal O-linked N-acetylglucosamine transferases (OGTs), suggesting that they may also have OGT activity. HvSPY has a locus distinct from that of Sin, a mutation that causes the constitutive GA responses of slender barley, which phenotypically resembles Arabidopsis spy mutants. The possibility that the HvSPY gene encodes a negative regulator of GA action was tested by expressing HvSPY in a barley aleurone transient assay system. HvSPY coexpression largely abolished GA3-induced activity of an α-amylase promoter. Surprisingly, HvSPY coexpression increased reporter gene activity from an abscisic acid (ABA)-inducible gene promoter (dehydrin), even in the absence of exogenous ABA. These results show that HvSPY modulates the transcriptional activities of two hormonally regulated promoters: negatively for a GA-induced promoter and positively for an ABA-induced promoter.

Original languageEnglish (US)
Pages (from-to)995-1007
Number of pages13
JournalPlant Cell
Issue number6
StatePublished - Jun 1998


Dive into the research topics of 'Identification of a negative regulator of gibberellin action, HvSPY, in barley'. Together they form a unique fingerprint.

Cite this