The PHOSPHATE1 genes participate in salt and Pi signaling pathways and play adaptive roles during soybean evolution

Yan Wang,Huihui Gao,Weiwei Zhu,Lingli He,Chaoying He,Qingshan Chen,Lixin Yan

doi:10.1186/s12870-019-1959-8

Abstract

BackgroundThe PHOSPHATE1 (PHO1) gene family plays diverse roles in inorganic phosphate (Pi) transfer and signal transduction, and plant development. However, the functions and diversification of soybean PHO1 family are poorly understood.ResultsCultivated soybean (Glycine max) was domesticated from wild soybean (Glycine soja). To illuminate their roles in this evolutionary process, we comparatively investigated the G. max PHO1 genes (GmPHO1) in Suinong 14 (SN14) and G. soja PHO1 genes (GsPHO1) in ZYD00006 (ZYD6). The sequences of the orthologous Gm-GsPHO1 pairs were grouped into two Classes. The expression of Class I in both SN14 and ZYD6 was widely but relatively high in developing fruits, whereas Class II was predominantly expressed in the roots. The whole family displayed diverse response patterns to salt stresses and Pi-starvation in roots. Between SN14 and ZYD6, most PHO1 genes responded similarly to salinity stresses, and half had sharp contrasts in response to Pi-starvation, which corroborated the differential response capacities to salinity and low-Pi stress between SN14 and ZYD6. Furthermore, in transgenic Arabidopsis plants, most Class II members and GmPHO1;H9 from Class I could enhance salt tolerance, while only two Class II genes (GmPHO1;H4 and GmPHO1;H8) differently altered sensitivity to Pi-starvation. The expression of critical genes was accordingly altered in either salt or Pi signaling pathways in transgenic Arabidopsis plants.ConclusionsOur work identifies some PHO1 genes as promising genetic materials for soybean improvement, and suggests that expression variation is decisive to functional divergence of the orthologous Gm-GsPHO1 pairs, which plays an adaptive role during soybean evolution.

Highlights

The PHOSPHATE1 (PHO1) gene family plays diverse roles in inorganic phosphate (Pi) transfer and signal transduction, and plant development
When the Arabidopsis PHO1 genes were included, we found that the functionally characterized AtPHO1;H4 (SHB1) gene belonged to Class I, whereas AtPHO1;H1 and
The present study investigated the divergence of Gs-GmPHO1 orthologous gene pairs in terms of sequences and expression patterns under different conditions, evaluated their roles in determining response capacity to salinity and Pi-starvation between soybean accessions and performed transgenic Arabidopsis analyses (Fig. 8) to provide further insights into the functional diversification and adaptive roles of the PHO1 gene family during soybean evolution

Summary

Introduction

The PHOSPHATE1 (PHO1) gene family plays diverse roles in inorganic phosphate (Pi) transfer and signal transduction, and plant development. Three PHO1 homologs (OsPHO1;1, OsPHO1;2, and OsPHO1;3) have been identified in the rice genome, but only OsPHO1;2 has been shown to play a role in loading Pi into the xylem [13] These observations suggest that this gene family plays diverse roles. In corroboration with this notion, members of the PHO1 gene family in Arabidopsis were found to participate in signal transduction, as well as plant growth and development. Arabidopsis PHO1 has been reported to play an important role in stomatal responses to ABA [18], suggesting a possible interaction among different signal transduction pathways in plants such as drought and salinity stresses

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