Genome-Wide Analysis of the RAV Family in Soybean and Functional Identification of GmRAV-03 Involvement in Salt and Drought Stresses and Exogenous ABA Treatment.

Shu-Ping Zhao,Shou-Cheng Chai,You-Zhi Ma,Yong-Bin Zhou,Dong-Hong Min,Ming Chen,Wei-Jun Zheng,Yan-Xia Wang,Xiao-Hong Zhang,Tai-Fei Yu,Zhao-Shi Xu,Wan Zhao

doi:10.3389/fpls.2017.00905

Abstract

Transcription factors play vital roles in plant growth and in plant responses to abiotic stresses. The RAV transcription factors contain a B3 DNA binding domain and/or an APETALA2 (AP2) DNA binding domain. Although genome-wide analyses of RAV family genes have been performed in several species, little is known about the family in soybean (Glycine max L.). In this study, a total of 13 RAV genes, named as GmRAVs, were identified in the soybean genome. We predicted and analyzed the amino acid compositions, phylogenetic relationships, and folding states of conserved domain sequences of soybean RAV transcription factors. These soybean RAV transcription factors were phylogenetically clustered into three classes based on their amino acid sequences. Subcellular localization analysis revealed that the soybean RAV proteins were located in the nucleus. The expression patterns of 13 RAV genes were analyzed by quantitative real-time PCR. Under drought stresses, the RAV genes expressed diversely, up- or down-regulated. Following NaCl treatments, all RAV genes were down-regulated excepting GmRAV-03 which was up-regulated. Under abscisic acid (ABA) treatment, the expression of all of the soybean RAV genes increased dramatically. These results suggested that the soybean RAV genes may be involved in diverse signaling pathways and may be responsive to abiotic stresses and exogenous ABA. Further analysis indicated that GmRAV-03 could increase the transgenic lines resistance to high salt and drought and result in the transgenic plants insensitive to exogenous ABA. This present study provides valuable information for understanding the classification and putative functions of the RAV transcription factors in soybean.

Highlights

Soybean (Glycine max L.) is an economically important crop that is used in human diets, animal feeds and for biodiesel production.soybean growth and productivity are greatly affected by environmental stresses such as drought and high soil salinity (Kang et al, 2009; Kidokoro et al, 2015)
The height of WT was slightly shorter than that of transgenic lines (Figure 9). These results indicated that overexpression of GmRAV-03 in Arabidopsis enhances plant insensitivity to the exogenous abscisic acid (ABA), suggesting that GmRAV03 may play an important role in ABA signaling during seed germination and early seedling development
Genome-wide analysis of the RAV family revealed the presence of 13 RAV members in soybean

Summary

INTRODUCTION

Soybean (Glycine max L.) is an economically important crop that is used in human diets, animal feeds and for biodiesel production. The expression of genes encoding transcription factors are induced or repressed and these function to further regulate plant responses to environmental stresses (Hao and TABLE 1 | Protein information for the soybean RAVs, including sequence ID, predicted protein sequence length, predicted molecular weight (MW), predicted isoelectric point (pI), and chromosome locations of the genes putatively encoding these proteins. The members of RAV family play important roles in plant physiological processes, such as leaf senescence, flowering development, organ growth, and hormone signaling. It was reported that the RAV1 transcription factor play important roles in positively regulating leaf senescence in Arabidopsis (Woo et al, 2010). The Arabidopsis NGATHA genes (NGA1-NGA4) which belong to RAV family play important roles in leaf and flower development. TEM1 and TEM2 which belong to RAV family can delay flowering by repressing the production of FLOWERINGLOCUS T (FT) and

MATERIALS AND METHODS

RESULTS

DISCUSSION