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OsBAK2/OsSERK2 Expression is Repressed by OsBZR1 to Modulate Brassinosteroid Response and Grain Length in Rice
- Source :
- Journal of Experimental Botany.
- Publication Year :
- 2023
- Publisher :
- Oxford University Press (OUP), 2023.
-
Abstract
- Brassinosteroids (BRs) are a class of polyhydroxylated steroidal phytohormones and essential for plant growth and development. Rice BRASSINOSTEROID-INSENSITIVE1 (BRI1)-ASSOCIATED RECEPTOR KINASES (OsBAKs) are plasma membrane (PM)-localized receptor kinases, belonging to the subfamily of leucine-rich repeat (LRR) receptor kinases. In Arabidopsis, BRs induce the formation of BRI1-BAK1 heterodimer complex and transmit the signal cascade to the BRASSINAZOLE RESISTANT1/bri1-EMS-SUPPRESSOR1 (BZR1/BES1) to regulate BR signaling. In rice, we found that OsBZR1 binds directly to the promoter of OsBAK2, not OsBAK1, and represses the expression of OsBAK2 to form a BR feedback inhibition loop. Additionally, the phosphorylation of OsBZR1 by OsGSK3 reduced its binding activity to OsBAK2 promoter. The osbak2 displays a typical BR deficient phenotype and negatively modulates the accumulation of OsBZR1. Interestingly, the grain length of osbak2 mutant was increased whereas the cr-osbak2/cr-osbzr1 double mutant restored the reduced grain length of cr-osbzr1 mutant, implying that the increased grain length of osbak2 may be due to the rice SERKs-dependent pathway. Our study reveals a novel mechanism of OsBAK2 and OsBZR1 engaging in a negative feedback loop to maintain rice BR homeostasis, facilitating to a deeper understanding of BR signaling network and grain length regulation in rice.
- Subjects :
- Physiology
Plant Science
Subjects
Details
- ISSN :
- 14602431 and 00220957
- Database :
- OpenAIRE
- Journal :
- Journal of Experimental Botany
- Accession number :
- edsair.doi...........7923aabb79aae9970795de9c29e8c9cb