What the study found
The study found that INDETERMINATE DOMAIN 5 (IDD5) in wheat and SEMI-DWARF 3 (SDW3) in barley are positive regulators of stem and leaf expansion. Both proteins physically interact with DELLA proteins, which are plant transcriptional regulators that help control growth through gibberellin, a plant hormone that promotes growth by triggering DELLA degradation.
Why the authors say this matters
The authors say this matters because DELLA proteins have already been important in crop improvement, including the semi-dwarf wheat alleles Rht-B1b and Rht-D1b. They conclude that understanding how DELLA proteins regulate growth is critical for refining breeding strategies, especially since some beneficial dwarfing alleles also reduce early vigor and nitrogen use efficiency.
What the researchers tested
The researchers identified the wheat and barley transcription factors IDD5 and SDW3 and tested their role in growth regulation. They examined physical interactions with DELLA proteins, looked at expression changes in gibberellin biosynthesis genes, and evaluated loss-of-function mutants in growth tests and field trials.
What worked and what didn't
IDD5 and SDW3 acted downstream of DELLA proteins and were described as key components of gibberellin-mediated growth responses. Altered expression of gibberellin biosynthesis genes suggested that IDD5 also contributes to gibberellin homeostasis. Loss-of-function mutations in IDD5 and SDW3 caused a gibberellin-insensitive semi-dwarf phenotype similar in height to the Rht-D1b Green Revolution allele; in field trials, idd5 lines had improved grain weight per spike but lower overall yield because they produced fewer spikes.
What to keep in mind
The abstract does not provide detailed limitations beyond noting that the field-trial outcome for idd5 lines involved a tradeoff between grain weight per spike and spike number. The findings are limited to wheat and barley and to the genes and growth responses described in the abstract.
Key points
- IDD5 in wheat and SDW3 in barley were identified as positive regulators of stem and leaf expansion.
- IDD5 and SDW3 physically interact with DELLA proteins and act downstream of them.
- Loss-of-function mutations in IDD5 and SDW3 produced a gibberellin-insensitive semi-dwarf phenotype.
- IDD5 may also contribute to gibberellin homeostasis through altered expression of gibberellin biosynthesis genes.
- In field trials, idd5 lines had higher grain weight per spike but lower overall yield because of fewer spikes.
Disclosure
- Research title:
- IDD5 and SDW3 control gibberellin-linked stem growth in wheat and barley
- Authors:
- Patrycja Sokolowska, Matthias Jöst, Wolfram Buss, Brett Ford, Peter Michael Chandler, Wolfgang Spielmeyer, Andrew L. Phillips, Alison K. Huttly, Danuše Tarkowská, Rocío Alarcón‐Reverte, Suzanne J. Clark, Stephen Pearce, Peter Hedden, Stephen G. Thomas
- Institutions:
- Agriculture and Food, Agriculture and Food, Agriculture and Food, Agriculture and Food, Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Commonwealth Scientific and Industrial Research Organisation, Commonwealth Scientific and Industrial Research Organisation, Commonwealth Scientific and Industrial Research Organisation, Commonwealth Scientific and Industrial Research Organisation, Czech Academy of Sciences, Institute of Experimental Botany, Czech Academy of Sciences, Institute of Experimental Botany, Rothamsted Research, Rothamsted Research, Rothamsted Research, Rothamsted Research, Rothamsted Research, Rothamsted Research, Rothamsted Research, Rothamsted Research
- Publication date:
- 2026-01-30
- OpenAlex record:
- View
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