Transcriptome analysis revealed the interaction among strigolactones, auxin, and cytokinin in controlling the shoot branching of rice
Strigolactones inhibit bud growth by negatively regulating the auxin transport without changing the auxin biosynthesis and suppressing the expression of A-ARR in buds.
Strigolactones (SLs) are important phytohormones associated with regulation of shoot branching in rice. Rice shoot branching is persuasively mediated by plant hormones like auxin, cytokinins (CKs) and SLs. The interactions among these hormones were diversely investigated by many researchers but remained a subject of debate. In the present study, the removal of panicle and application of subsequent synthetic SLs were used to regulate rice bud growth on node 2 (the second node from panicle) at full heading stage. The bud growth was significantly induced after panicle removal but GR24 (synthetic SLs) application inhibited it, along with variations in endogenous hormone contents in bud. RNA samples from buds were subjected to RNA sequencing through Illumina HiSeq 2000 (RNA-seq). Comparison of transcript expression levels among three treatments, viz. (1) intact (Co), (2) removed panicle (RP) and (3) RP combined with synthetic SL GR24 (GR) revealed the involvement of numerous genes associated with hormone signal transduction. GR24 supply minimized the RP-induced enhancement of auxin early response genes, independent of ARF. CK signal transduction was also induced by RP, but type-A ARR were the only genes responding to GR without any other CK signal associated genes. Additionally, RP and GR can also modulate auxin transport and CK degradation by regulating the genes’ expression involved in the biosynthesis of flavonoid, phenylpropanoid and benzoxazinoid. Contemplating the results obtained so far, it is possible to open new vistas of research to reveal the interactions among SLs, auxin and CK in controlling the shoot branching of rice.
KeywordsRice Tiller bud RNA-seq Strigolactone Cytokinin Auxin
This work was supported by the Ministry of National Science and Technology of China (Project no. 31371569), the Science and Technology Department of China (Project no. 2013BAD07B09), and the Science and Technology Department of Jiangsu Province (Project no. BE2014393).
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Conflict of the interest
The authors have no conflicts of the interest to declare.
- Chao WS, Dogramaci M, Horvath DP, Anderson JV, Foley ME (2016) Phytohormone balance and stress-related cellular responses are involved in the transition from bud to shoot growth in leafy spurge. BMC Plant Biol 16:47. https://doi.org/10.1186/s12870-016-0735-2 CrossRefPubMedPubMedCentralGoogle Scholar
- Hanada K (1993) Tiller. In: Matsuo THK (ed) Science of the rice plant, vol 1. Food and Agriculture Policy Research Center, Tokyo, pp 222–229Google Scholar
- Imamura A et al (1999) Compilation and characterization of Arabidopsis thaliana response regulators implicated in His-Asp phosphorelay signal transduction. Plant Cell Physiol 40:733–742. https://doi.org/10.1093/oxfordjournals.pcp.a029600 CrossRefPubMedGoogle Scholar
- Johnson X, Brcich T, Dun EA, Goussot M, Haurogne K, Beveridge CA, Rameau C (2006) Branching genes are conserved across species. Genes controlling a novel signal in pea are coregulated by other long-distance signals. Plant Physiol 142:1014–1026. https://doi.org/10.1104/pp.106.087676 CrossRefPubMedPubMedCentralGoogle Scholar
- Kiba T, Taniguchi M, Imamura A, Ueguchi C, Mizuno T, Sugiyama T (1999) Differential expression of genes for response regulators in response to cytokinins and nitrate in Arabidopsis thaliana. Plant Cell Physiol 40:767–771. https://doi.org/10.1093/oxfordjournals.pcp.a029604 CrossRefPubMedGoogle Scholar
- Nordstrom A, Tarkowsk T, Tarkowska D, Norbaek R, Åstot C, Dolezal D, Sandberg G (2004) Auxin regulation of cytokinin biosynthesis in Arabidopsis thaliana: a factor pf potential importance for auxin cytokinin regulated development. Proc Natl Acad Sci USA 101:8039–8044. https://doi.org/10.1073/pnas.0402504101 CrossRefPubMedGoogle Scholar
- Peer WA, Bandyopadhyay A, Blakeslee JJ, Makam SN, Chen RJ, Masson PH, Murphy AS (2004) Variation in expression and protein localization of the PIN family of auxin efflux facilitator proteins in flavonoid mutants with altered auxin transport in Arabidopsis thaliana. Plant Cell 16:1898–1911. https://doi.org/10.1105/tpc.021501 CrossRefPubMedPubMedCentralGoogle Scholar
- Xu J, Ding C, Ding Y, Tang S, Zha M, Luo B, Wang S (2014) A proteomic approach to analyze differential regulation of proteins during bud outgrowth under apical dominance based on the auxin transport canalization model in rice (Oryza sativa L.). J Plant Growth Regul 34:122–136. https://doi.org/10.1007/s00344-014-9450-0 CrossRefGoogle Scholar
- Xu J, Zha M, Li Y, Ding Y, Chen L, Ding C, Wang S (2015) The interaction between nitrogen availability and auxin, cytokinin, and strigolactone in the control of shoot branching in rice (Oryza sativa L.). Plant Cell Rep 34:1647–1662. https://doi.org/10.1007/s00299-015-1815-8 CrossRefPubMedGoogle Scholar