Green revolution: a mutant gibberellin-synthesis gene in rice. Sasaki A,Ashikari M,Ueguchi-Tanaka M,Itoh H,Nishimura A,Swapan D,Ishiyama K,Saito T,Kobayashi M,Khush G S,Kitano H,Matsuoka M Nature The chronic food shortage that was feared after the rapid expansion of the world population in the 1960s was averted largely by the development of a high-yielding semi-dwarf variety of rice known as IR8, the so-called rice 'green revolution'. The short stature of IR8 is due to a mutation in the plant's sd1 gene, and here we identify this gene as encoding an oxidase enzyme involved in the biosynthesis of gibberellin, a plant growth hormone. Gibberellin is also implicated in green-revolution varieties of wheat, but the reduced height of those crops is conferred by defects in the hormone's signalling pathway. 10.1038/416701a

'Green revolution' genes encode mutant gibberellin response modulators. Peng J,Richards D E,Hartley N M,Murphy G P,Devos K M,Flintham J E,Beales J,Fish L J,Worland A J,Pelica F,Sudhakar D,Christou P,Snape J W,Gale M D,Harberd N P Nature World wheat grain yields increased substantially in the 1960s and 1970s because farmers rapidly adopted the new varieties and cultivation methods of the so-called 'green revolution'. The new varieties are shorter, increase grain yield at the expense of straw biomass, and are more resistant to damage by wind and rain. These wheats are short because they respond abnormally to the plant growth hormone gibberellin. This reduced response to gibberellin is conferred by mutant dwarfing alleles at one of two Reduced height-1 (Rht-B1 and Rht-D1) loci. Here we show that Rht-B1/Rht-D1 and maize dwarf-8 (d8) are orthologues of the Arabidopsis Gibberellin Insensitive (GAI) gene. These genes encode proteins that resemble nuclear transcription factors and contain an SH2-like domain, indicating that phosphotyrosine may participate in gibberellin signalling. Six different orthologous dwarfing mutant alleles encode proteins that are altered in a conserved amino-terminal gibberellin signalling domain. Transgenic rice plants containing a mutant GAI allele give reduced responses to gibberellin and are dwarfed, indicating that mutant GAI orthologues could be used to increase yield in a wide range of crop species. 10.1038/22307

Wheat gibberellin oxidase genes and their functions in regulating tillering. PeerJ Multiple genetic factors control tillering, a key agronomy trait for wheat ( L.) yield. Previously, we reported a mutant () derived from wheat cultivar Guomai 301, and found that the contents of gibberellic acid 3 (GA) in the tiller primordia of were significantly higher. Transcriptome analysis indicated that some wheat gibberellin oxidase () genes , , , , and were differentially expressed in . Therefore, this study systematically analyzed the roles of gibberellin oxidase genes during wheat tillering. A total of 63 genes were identified by whole genome analysis. The TaGAoxs were clustered to four subfamilies, GA20oxs, GA2oxs, GA3oxs and GA7oxs, including seven subgroups based on their protein structures. The promoter regions of genes contain a large number of -acting elements closely related to hormone, plant growth and development, light, and abiotic stress responses. Segmental duplication events played a major role in expansion. Compared to , the gene collinearity degrees of the were significantly higher among wheat, rice and maize. genes showed tissue-specific expression patterns. The expressions of genes (, , and ) were significantly affected by exogenous GA applications, which also significantly promoted tillering of Guomai 301, but didn't promote . overexpression transgenic wheat lines were obtained by mediated transformation. Genomic PCR and first-generation sequencing demonstrated that the gene was integrated into the wheat genome. Association analysis of expression level and tiller number per plant demonstrated that the tillering capacities of some transgenic lines were increased. These data demonstrated that some as well as GA signaling were involved in regulating wheat tillering, but the GA signaling pathway was disturbed in . This study provided valuable clues for functional characterization of genes in wheat. 10.7717/peerj.15924

Reducing brassinosteroid signalling enhances grain yield in semi-dwarf wheat. Nature Modern green revolution varieties of wheat (Triticum aestivum L.) confer semi-dwarf and lodging-resistant plant architecture owing to the Reduced height-B1b (Rht-B1b) and Rht-D1b alleles. However, both Rht-B1b and Rht-D1b are gain-of-function mutant alleles encoding gibberellin signalling repressors that stably repress plant growth and negatively affect nitrogen-use efficiency and grain filling. Therefore, the green revolution varieties of wheat harbouring Rht-B1b or Rht-D1b usually produce smaller grain and require higher nitrogen fertilizer inputs to maintain their grain yields. Here we describe a strategy to design semi-dwarf wheat varieties without the need for Rht-B1b or Rht-D1b alleles. We discovered that absence of Rht-B1 and ZnF-B (encoding a RING-type E3 ligase) through a natural deletion of a haploblock of about 500 kilobases shaped semi-dwarf plants with more compact plant architecture and substantially improved grain yield (up to 15.2%) in field trials. Further genetic analysis confirmed that the deletion of ZnF-B induced the semi-dwarf trait in the absence of the Rht-B1b and Rht-D1b alleles through attenuating brassinosteroid (BR) perception. ZnF acts as a BR signalling activator to facilitate proteasomal destruction of the BR signalling repressor BRI1 kinase inhibitor 1 (TaBKI1), and loss of ZnF stabilizes TaBKI1 to block BR signalling transduction. Our findings not only identified a pivotal BR signalling modulator but also provided a creative strategy to design high-yield semi-dwarf wheat varieties by manipulating the BR signal pathway to sustain wheat production. 10.1038/s41586-023-06023-6

The induction of sensitivity to gibberellin in aleurone tissue of developing wheat grains : I. The effect of dehydration. Armstrong C,Black M,Chapman J M,Norman H A,Angold R Planta Aleurone layers from immature developing wheat grains (Triticum aestivum L. cvs. Sappo. and Champlein), though normally insensitive, can be made to produce α-amylase in response to gibberellic acid by subjecting the grains to a period of enforced dehydration prior to introduction to the hormone. The change in sensitivity appears to depend upon the water content of the tissue, water levels of below approximately 25% being critical for the effect. Grain detachment or duration of drying apparently do not qualitatively influence the development of sensitivity to gibberellic acid. Enhanced sensitivity resulting from drying is not caused by changes in gibberellic acid uptake. A possible mechanism for the change in sensitivity of aleurone cells might be through structural alterations in cell membranes. 10.1007/BF00403003