BACKGROUND: The brassinosteroid (BR) plant hormones regulate numerous developmental processes, including those determining stem height, leaf angle, and grain size that have agronomic relevance in cereals. Indeed, barley (Hordeum vulgare) varieties containing uzu alleles that impair BR perception through mutations in the BR receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1) exhibit a semi-dwarf growth habit and more upright leaves suitable for high-density planting. We used forward and reverse genetic approaches to develop novel BRI1 alleles in wheat (Triticum aestivum L.) and investigated their potential for crop productivity improvement. RESULTS: The combination of ethyl methanesulfonate-induced mutations introducing premature stop codons in all three homoeologous TaBRI1 genes resulted in severe dwarfism, malformed leaves and sterility as observed in bri1 mutants in other species. Double mutants had reduced flag-leaf angles (FLAs) conferring a more upright canopy but exhibited no differences in height or grain weight. In a targeted forward genetics screen using a double mutant, we identified two BR-insensitive lines with reduced height and FLA that contained amino acid substitutions in conserved regions of BRI-A1. The less severe mutant had a 56% reduction in FLA and was 35% shorter than the wild type, although seed set, seed area and grain weights were also reduced. The most severe mutants contained elevated levels of bioactive BRs and increased expression of BR-biosynthesis genes consistent with reduced feedback suppression of biosynthesis. CONCLUSION: Our study gives a better understanding of BRI1 function in wheat and provides mutants that could potentially be explored for improving grain yields when sown at high density.

• Klíčová slova
• BR insensitivity, Brassinosteroids, EMS-mutagenesis, Semi-dwarf, Upright leaf angles, Wheat,
• MeSH
• brassinosteroidy metabolismus   MeSH
• fenotyp MeSH
• listy rostlin genetika   anatomie a histologie   růst a vývoj   MeSH
• mutace MeSH
• pšenice * genetika   anatomie a histologie   růst a vývoj   metabolismus   MeSH
• rostlinné proteiny * genetika   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• brassinosteroidy MeSH
• rostlinné proteiny * MeSH

It has been almost a century since biologically active gibberellin (GA) was isolated. Here, we give a historical overview of the early efforts in establishing the GA biosynthesis and catabolism pathway, characterizing the enzymes for GA metabolism, and elucidating their corresponding genes. We then highlight more recent studies that have identified the GA receptors and early GA signaling components (DELLA repressors and F-box activators), determined the molecular mechanism of DELLA-mediated transcription reprograming, and revealed how DELLAs integrate multiple signaling pathways to regulate plant vegetative and reproductive development in response to internal and external cues. Finally, we discuss the GA transporters and their roles in GA-mediated plant development.

• MeSH
• gibereliny * metabolismus   MeSH
• regulace genové exprese u rostlin MeSH
• regulátory růstu rostlin metabolismus   MeSH
• rostlinné proteiny metabolismus   genetika   MeSH
• signální transdukce MeSH
• vývoj rostlin genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• gibereliny * MeSH
• regulátory růstu rostlin MeSH
• rostlinné proteiny MeSH