Identification and functional characterization of a novel BEL1-LIKE homeobox transcription factor GmBLH4 in soybean
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The interaction between BEL1- and KNOTTED1-type homeobox transcription factors from TALE (Three-Amino-acid-Loop Extension) class plays key roles in plant growth and development. In our previous study, a soybean KNOTTED1-like gene GmSBH1, which played important roles in soybean growth and development as well as in response to high temperature and humidity (HTH) stress was identified. In the present study, 15 GmSBH1-interacting candidate proteins were identified by yeast two-hybrid system. From the 15 candidate proteins, a novel BEL1-LIKE homeodomain 4 protein, GmBLH4, was selected to isolate and characterize through sequence alignment, phylogenetic analysis and subcellular localization. GmBLH4 showed tissues specific expression and was involved in response to HTH stress in developing seeds. Overexpression of GmBLH4 in Arabidopsis altered leaf phenotype and silique length, and enhanced seed tolerance to HTH stress. Glutathione-S-transferase pull-down (GST) and bimolecular fluorescence complementation (BiFC) assays confirmed that GmBLH4 specifically interacted with GmSBH1 in vivo and in vitro. The conserved domains of GmSBH1 and GmBLH4 were sufficient for their interaction in yeast expression system. Our results indicated that GmBLH4 might heterodimerize with GmSBH1 to form functional complexes and function in modulating plant growth and development as well as in response to HTH stress in soybean.
KeywordsSoybean growth and development High temperature and humidity stress Leaf phenotype GmBLH4 Shoot apical meristem Interaction
We gratefully acknowledge the partial financial support from the National Natural Science Foundation of China (31101212, 30971840, 31171572, 31371711, 31671772), the projects supported by the Shanghai Committee of Agriculture, China [Hunongkegongzi (2013), No. 1-2], and the Excellent Young Talents Program of Anhui Province Colleges and Universities of China (2012 SQRL143) for this research.
The work presented here was carried out in collaboration among all authors. YT carried out the most of the laboratory experiments; MC and PQ carried out yeast hybrid assay; SW and LH carried out the extraction of protoplasts; YZ, XY and ZW carried out the BiFC assay. WG, HM and YS designed the experiments and wrote the manuscript. All authors have contributed to read and approved the final manuscript.
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Conflict of interest
The authors declare no competing financial interests.
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