Identification of ZOUPI Orthologs in Soybean Potentially Involved in Endosperm Breakdown and Embryogenic Development.

Yaohua Zhang,Xin Li,Xianzhong Feng,Suxin Yang

doi:10.3389/fpls.2017.00139

Abstract

Soybean (Glycine max Merr.) is the world’s most widely grown legume and provides an important source of protein and oil. Improvement of seed quality requires deep insights into the genetic regulation of seed development. The endosperm serves as a temporary source of nutrients that are transported from maternal to filial tissues, and it also generates signals for proper embryo formation. Endosperm cell death is associated with the processes of nutrient transfer and embryo expansion. The bHLH domain transcription factor AtZHOUPI (AtZOU) plays a key role in both the lysis of the transient endosperm and the formation of embryo cuticle in Arabidopsis thaliana. There are two copies of soybean GmZOU (GmZOU-1 and GmZOU-2), which fall into the same phylogenetic clade as AtZOU. These two copies share the same transcription orientation and are the result of tandem duplication. The expression of GmZOUs is limited to the endosperm, where it peaks during the heart embryo stage. When the exogenous GmZOU-1 and GmZOU-2 were expressed in the zou-4 mutant of Arabidopsis, only GmZOU-1 partially complemented the zou mutant phenotype, as indicated by endosperm breakdown and embryo cuticle formation in the transgenic lines. This research confirmed that the GmZOU-1 is a ZOU ortholog that may be responsible for endosperm breakdown and embryo cuticle formation in soybean.

Highlights

Soybean is a major global economic crop and a source of carbohydrates, protein, oil, and other nutrients for humans and animals (Hou et al, 2009)
In order to investigate the regulating pathway of endosperm breakdown and the communication between endosperm and embryo in soybean, we identified a ZOU ortholog gene, which complements the Arabidopsis zou mutant phenotype allowing the recovery of endosperm breakdown and embryo cuticle formation
The two highest scores were obtained for the genes models Glyma.02G103200 and Glyma.02G103100, and the corresponding genes were designated as GmZOU-1 and GmZOU-2, respectively

Summary

Introduction

Soybean is a major global economic crop and a source of carbohydrates, protein, oil, and other nutrients for humans and animals (Hou et al, 2009). The endosperm plays important roles in metabolite production, transport, and accumulation in the embryo (Melkus et al, 2009). ZOUPI Orthologs in Soybean is believed to participate in the flux control of nutrients delivered by the vascular tissues of the parental plants to the embryo (Abbadi and Leckband, 2011). The soluble metabolites are temporarily stored in the endosperm vacuole with the concentration developmentally controlled, and influence metabolite accumulation in embryo (Melkus et al, 2009). In addition to nutrient transport and metabolism, the endosperm plays a role in controlling the sizes of the embryo and seed, the precise mechanism is still unknown (Luo et al, 2005)

Methods

Results

Conclusion