Chinese Bulletin of Botany ›› 2019, Vol. 54 ›› Issue (2): 185-193.DOI: 10.11983/CBB19013

Special Issue: 逆境生物学专辑 (2019年54卷2期)

• EXPERIMENTAL COMMUNICATIONS • Previous Articles     Next Articles

Functional Analysis of Brassinosteroids in Salt Stress Responses in Rice

Lulu Li,Wenchao Yin,Mei Niu,Wenjing Meng,Xiaoxing Zhang,Hongning Tong()   

  1. Institute of Crop Sciences, Chinese Academy of Agricultural Sciences/National Key Facility for Crop Gene Resources and Genetic Improvement, Beijing 100081, China
  • Received:2019-01-18 Accepted:2019-03-19 Online:2019-03-10 Published:2019-09-01
  • Contact: Hongning Tong

Abstract: Brassinosteroids (BRs) are a class of steroid phytohormones that play diverse roles in plant growth and development and stress responses. Rapid progresses have been made in how BRs regulate plant growth and development in recent years. However, the roles of BRs in stress response in Oryza sativa remain unclear. Here, we investigated the relation between salinity stress and BR synthesis in rice. Both salt stress and abscisic acid, the well-known stress hormone, strongly inhibited the expression of two BR-synthetic genes, D2 and D11. In addition, both d2-2, the BR synthetic mutant, and d61-1, the BR receptor mutant, showed impaired tolerance to salt stress. Moreover, by using transgenic plants overexpressing OsBZR1, the key BR signaling transcriptional factor, we found that BRs strongly induced dephosphorylation of OsBZR1, but high concentrations of salt suppressed OsBZR1 protein accumulation as well as its dephosphorylation. Furthermore, transcriptome analyses revealed that 38.4% of BR-regulated genes were also regulated by high concentrations of salt, and importantly, 91.5% of the co-regulated genes are consistently up- or downregulated by both BR and salt. Gene Ontology analyses revealed that these overlapping genes were highly enriched in the biological process “response to stimulus”. Taken together, our results suggest that BRs contribute to salt stress tolerance, and salt stress suppresses BR synthesis to restrict rice growth.

Key words: brassinosteroid, rice, salt stress, abscisic acid, OsBZR1