MADS-Box Protein Complex VvAG2, VvSEP3 and VvAGL11 Regulates the Formation of Ovules in Vitis vinifera L. cv. 'Xiangfei'.

Yan Wang,Liang Hong,Jianfang Hu,Pingyin Guan,Jiang Wu,Zhenhua Liu,Jinjun Liang,Yangmei Ren

doi:10.3390/genes12050647

Abstract

The phenomenon of multi-carpel and multi-ovule exists in the grapevine cultivar ‘Xiangfei’, but the mechanism of ovule formation is seldom reported. In this study, we observed the ovule formation process by using ‘Xiangfei’ grapes. The role of the VvAG2 (VvAGAMOUS) gene in ovule formation was identified, and we explored the relationship between VvAG2, VvSEP3(VvMADS4) and VvAGL11(VvMADS5) proteins. The results showed that the ovule primordium appeared when the inflorescence length of ‘Xiangfei’ grapes were 4–5 cm long; the relative expression levels of VvAG2, VvAGL11 and VvSEP3 genes were higher during ovule formation, and the expression levels of VvAG2 gene was the highest. Transgenic tomato (Solanum lycopersicum) plants expressing VvAG2 produced higher numbers of ovules and carpels than the wild type. Moreover, yeast two-hybrid and yeast three-hybrid experiments demonstrated that VvSEP3 acts as a bridge and interacts with VvAG2 and VvAGL11 proteins, respectively. Meanwhile, a homodimer can be formed between VvSEP3 and VvSEP3, but there was no interaction between VvAG2 and VvAGL11. These findings suggest that the VvAG2 gene is involved in the formation of ovules, and VvAG2/VvSEP3 together with VvAGL11/VvSEP3 can form a tetrameric complex. In summary, our data showed that VvAG2 along with VvSEP3 and VvAGL11 jointly regulate the ovule formation of ‘Xiangfei’ grapes.

Highlights

We demonstrated that the VvAG2 gene along with VvSEP3 and VvAGL11 is involved in the ovule formation of ‘Xiangfei’ grapes
In the absence of VvSEP3, the yeast strains could not grow on the medium, which indicated that there was no direct interaction between VvAG2 and VvAGL11. These results demonstrated that the interaction between VvAG2 and VvAGL11 was linked through VvSEP3
VvSEP3 can form a homodimer and interact with VvAG2 and VvAGL11. These results indicate that VvAG2 and VvAGL11 can form tetramers by interacting with VvSEP3, where VvSEP3 acts as a bridge in the tetramer

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. As the site of double fertilization in angiosperms, ovules are the precursor of seeds. The efficient formation and development of numerous ovules are essential for the sexual reproduction and progeny reproduction of plants [1,2]. Ovule development takes place inside the gynoecium, and the ovule primordium is initiated by periclinal divisions in the subepidermal tissue of the placenta [3]. The ovule has a complex morphological structure and is composed of the funiculus, integument, micropyle and nucellus. The funiculus supports the ovule and plays a role in transporting nutrients. The integument is usually divided into two protective layers—the inner integument and outer integument—

Methods

Results

Conclusion