Author:
Sun Maotong,Wang Dongyue,Liu Cuishuang,Liu Yuan,Niu Muge,Wang Jinnan,Li Jihong
Abstract
Abstract
Background
Strigolactones (SLs) are important phytohormones that can regulate branch development in plants. Although SUPPRESSOR of MAX2 1-LIKE proteins (SMXLs) play a crucial role in SL signaling transduction, the SMXL gene family has not been well characterized in poplar.
Results
In this study, 12 members of the poplar SMXL gene family were identified and phylogenetically classified into four clades. Motif and 3D structural analyses revealed that PtSMXL proteins are structurally very conserved; however, the P-loop NTPase domain at the C-terminal was found to vary substantially among clades. A genomic collinearity analysis indicated that PtSMXL gene family members have expanded during recent genome doubling events in poplar, with all gene pairs subsequently undergoing purifying selection. According to a Cis-element analysis, PtSMXL promoters contain many light-responsive elements. In an expression pattern analysis, all 12 PtSMXL genes displayed tissue-specific expression, especially PtSMXL8a. PtSMXL7b expression was significantly downregulated after axillary bud growth begins. In addition, the expressions of PtSMXL7b and PtSMXL8a were highly induced by 2 μM GR24, a synthetic SL analog, thus suggesting that these genes are involved in SL-regulated axillary bud growth. In a yeast two-hybrid assay, only PtSMXL7b in clade II was able to interact with the SL receptor PtD14a in an SL dependent manner, which indicates that PtSMXL7b may be the functional homolog of D53/SMXL6/7/8 in poplar. Finally, we established its ability to affect axillary bud growth by constructing poplar overexpressing the PtSMXL7b gene.
Conclusions
Our findings may inform future research on the functions of SMXLs in poplar, especially with respect to branch development.
Funder
the Major Science and Technology Projects for the Cultivation of New Varieties of Genetically Modifed Organisms
the Agricultural Breeding Program of Shandong Province
Publisher
Springer Science and Business Media LLC
Cited by
4 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献