Brachytic 1 of barley (Hordeum vulgare L.) encodes the α subunit of heterotrimeric G protein

Abstract

Physiological and molecular biological analysis of the dwarf barley (Hordeum vulgare L.) mutant brachytic 1 (brh1) was conducted. The root responses of brh1 to brassinolide were weaker than those of wild type, but the responses of leaf segments of dark-grown plants were not. Responses of brh1 to gibberellin A were similar to or slightly stronger than those of wild type. Endogenous levels of these hormones in young seedlings were not clearly different between brh1 and wild type. Skotomorphogeneses of brh1 were similar to those of wild type. Some of these physiological characteristics of brh1 resemble those of the dwarf rice (Oryza sativa L.) mutant daikoku (dwarf1; d1), whose dwarfism is caused by a mutation in the heterotrimeric G protein α (Gα) subunit. A database search indicated that the barley Gα gene is located near the locus where Brh1 has already been genetically mapped. Sequences of the Gα gene and cDNAs of five brh1 alleles contained substitutions and a deletion that lead to the production of abnormal Gα proteins. These results indicate that the phenotype of brh1, similarly to that of d1, is caused by mutations in an orthologous gene encoding Gα.

Genetics of barley tiller and leaf development

“…Recently, Ito et al () explored the barley Brh1 locus and identified some mutants resembling the rice dwarf mutant, daikoku ( dwarf1 ; d1 ) (Akemin ; Kadam ). The daikoku mutant has a mutation in the heterotrimeric G protein α subunit (Gα) (Ashikari et al , Fujisawa et al ).…”

Crosstalk of the Brassinosteroid Signalosome with Phytohormonal and Stress Signaling Components Maintains a Balance between the Processes of Growth and Stress Tolerance

“…RGA1 mediates a crosstalk between the BR and GA signaling pathways [ 299 ]. Recently, the barley Brachytic1 gene, which encodes the alpha subunit of the heterotrimeric G protein has been identified and functionally analyzed [ 319 , 320 ].…”

How plants grow up

“…Potential partners linking meristem maintenance and stem elongation, especially in response to environmental cues, are heterotrimeric G‐proteins. For instance, a major dwarfing locus in rice, DENSE PANICLE1 (DEP1) and barley ( HvDEP1 ) encodes a Gγ subunit (Huang et al ; Wendt et al ; Xu et al ) while defective alleles in genes encoding the Gα subunit in rice (‘ daikoku ’ dwarf1 , Ashikari et al ; Fujisawa et al ), barley ( brachytic1 , Ito et al ; Braumann et al ), maize ( compact plant2 , ct2 , Bommert et al ) and Arabidopsis ( gpa1 , Ullah et al ) confer compact shoots due to reduced axial proliferation. In rice, DWARF1 interacts with GA and BR signaling to control height (Ashikari et al ; Oki et al ).…”