Genome-wide survey of G\u03b3 subunit gene family in eight Rosaceae and expression analysis of PbrGGs in pear (Pyrus bretschneideri)

Guodong Chen,Xin Qiao,Yang Li,Cong Jin,Rui Cheng,Jizhong Wang,Weike Duan

doi:10.1186/s12870-021-03250-9

Guodong Chen, Xin Qiao + Show 5 more

Open Access

https://doi.org/10.1186/s12870-021-03250-9

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Abstract

BackgroundHeterotrimeric G-proteins, composed of Gα, Gβ and Gγ subunits, are important signal transmitters, mediating the cellular response to multiple stimuli in animals and plants. The Gγ subunit is an essential component of the G-protein, providing appropriate functional specificity to the heterotrimer complex and has been well studied in many species. However, the evolutionary history, expression pattern and functional characteristics of Gγ subunits has not been explored in the Rosaceae, representing many important fruit crops.ResultsIn this study, 35 Gγ subunit genes were identified from the eight species belonging to the Rosaceae family. Based on the structural gene characteristics, conserved protein motifs and phylogenetic analysis of the Gγ subunit genes, the genes were classified into three clades. Purifying selection was shown to play an important role in the evolution of Gγ subunit genes, while a recent whole-genome duplication event was the principal force determining the expansion of the Gγ subunit gene family in the subfamily Maloideae. Gγ subunit genes exhibited diverse spatiotemporal expression patterns in Chinese white pear, including fruit, root, ovary and bud, and under abiotic stress conditions, the relative expression of Gγ subunit genes were up-regulated or down-regulated. In addition, seven of the Gγ subunit proteins in pear were located on the plasma membrane, in the cytoplasm or nucleus.ConclusionOverall, this study of the Gγ subunit gene family in eight Rosaceae species provided useful information to better understand the evolution and expression of these genes and facilitated further exploration of their functions in these important crop plants.

Highlights

Heterotrimeric G-proteins, composed of Gα, Gβ and Gγ subunits, are important signal transmitters, mediating the cellular response to multiple stimuli in animals and plants
The Gγ subunit gene family in the Rosaceae To identify the members of the Gγ subunit gene family in the Rosaceae, we searched the entire genome sequences of each of the eight Rosaceae species, using two strategies: one approach was to use a Hidden Markov Model (HMM) file of the Gγ subunit gene domain (PF00631.22) from Pfam to screen the genomes of the eight Rosaceae species, whereas the other was to use the Arabidopsis amino acid sequence of the Gγ subunit as queries with which to carry out BLASTP searches against the genome databases of each of the eight Rosaceae species
A whole-genome duplication (WGD) event strongly contributed to the expansion of the Gγ subunit gene family in species of the Maloideae subfamily, whereas singleton and dispersed duplication events played key roles in the expansion of the Gγ subunit gene family in species of the Prunoideae and Rosoideae subfamilies

Summary

Introduction

Heterotrimeric G-proteins, composed of Gα, Gβ and Gγ subunits, are important signal transmitters, mediating the cellular response to multiple stimuli in animals and plants. The type III Gγ subunits, represented by GmGγ8, GmGγ9 and GmGγ10 in soybean and AGG3 in Arabidopsis [12, 19, 20], have been recently discovered and are novel, plantspecific proteins that possess unique features compared with all other Gγ subunits [21]. These proteins are almost twice as large as the type I or type II Gγ subunits, and contain a modular structure, with a Gγ-like domain at its N-terminus, followed possibly by a transmembrane domain and a long cysteine-rich C-terminal region [17]

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