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. 2021 Oct 15;21(1):471.
doi: 10.1186/s12870-021-03250-9.

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

Guodong Chen  1 , Yang Li  2 , Xin Qiao  3 , Weike Duan  2 , Cong Jin  2 , Rui Cheng  4 , Jizhong Wang  2
Affiliations

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

Guodong Chen et al. BMC Plant Biol. .

Abstract

Background: 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 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.

Results: In 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.

Conclusion: Overall, 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.

Keywords: Abiotic stress; Expression pattern; Gγ subunit; Pear; Subcellular localization.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
The evolutionary relationships and genome information of eight Rosaceae species. Blue and orange stars represent the divergent events in the eight species. The blue star indicates the occurrence of the ancient whole-genome duplication γ event (~300 mya) in all members of the Rosaceae; the orange star indicates the occurrence of the recent, lineage-specific WGD event (30~45 mya) in apple and pear. The data were downloaded from NCBI Taxonomy common tree (http://www.ncbi.nlm.nih.gov/Taxonomy/CommonTree/wwwcmt.cgi), and the phylogenetic tree was constructed using MEGA6 software
Fig. 2
Fig. 2
Phylogenetic tree, structural gene features and conserved protein motifs of the Gγ subunit genes in the eight Rosaceae species. A The phylogenetic tree was generated using the amino acid sequences encoded by each of 35 Gγ subunit genes with the Neighbor-Joining method and 1,000 bootstrap replicates. Different colors in the branches indicated the different subunit type. B Gene structural analysis, the orange boxes, black lines and green boxes in the gene structural diagram represent coding sequences (CDS), introns and untranslated regions (UTRs), respectively; gene models are drawn to scale as indicated on the x-axis. C Conserved motif analysis: fifteen distinct motifs (motifs 1 to 15) were identified with the MEME tool and the representation of each motif was illustrated with a different color. The lengths and positions of the colored blocks correspond to the lengths and positions of the motifs in the individual protein sequences, respectively
Fig. 3
Fig. 3
The number of Gγ subunit gene pairs from different origins in the eight Rosaceae species. The number of different modes of duplicated Gγ subunit gene pairs was determined by MCScanX and presented by GraphPad Prism 8 software. The x-axis in the lower histogram indicates the number of Gγ subunit genes. The x-axis of the upper-right histogram indicates the percentage frequency of each duplicated event. The y-axis of both histograms indicates the different species. Different color bars represent different duplication events
Fig. 4
Fig. 4
Distribution and collinearity of Gγ subunit genes in the eight Rosaceae species. The circular forms of the chromosomes of different species are marked in different colors. The red lines around the circumference of the circle mark the gene positions. The lines in different colors inside the circle represent the collinearity relationships among the genes from the eight Rosaceae species
Fig. 5
Fig. 5
Distribution of the mean Ks and Ka/Ks values of Gγ subunit genes in the eight Rosaceae species. A The mean Ks values represent the times of Gγ subunit gene divergence in the eight Rosaceae species. B Ka/Ks ratios represent the driving forces behind duplicated Gγ subunit gene evolution in the eight Rosaceae species
Fig. 6
Fig. 6
Expression analysis of seven PbrGG genes in different tissues. The relative transcript abundance levels of PbrGG genes were assessed by qPCR in various tissues of Chinese white pear. Total RNA was extracted from the root, leaf, stem, petal, bud, sepal, fruit, ovary, pollen and pollen tubes. For each gene, the relative expression levels were obtained by normalization with pear Actin. Data are shown as mean ± standard deviation
Fig. 7
Fig. 7
Expression patterns of PbrGG genes under abiotic stress. The relative expression levels of PbrGG genes were analyzed by qRT-PCR, and the samples were harvested from roots after N-deficiency treatment for five days; and the samples were harvested from leaves after ABA treatment for 6 h. For each gene, the relative expression levels were acquired by normalization to that of pear Actin. The error bars indicate standard deviations. Asterisks indicate a significant difference (*P < 0.05) compared with CK after abiotic stress treatment. Data are expressed as mean ± standard deviation
Fig. 8
Fig. 8
Subcellular localization of three PbrGG proteins. Seven PbrGG-GFP fusion proteins, with 35s-GFP as the control, were expressed transiently in tobacco leaves in an independent manner, and the results were visualized by laser confocal microscopy. The merged images include the chloroplast autofluorescence channel (first panels) and the green fluorescence channel (second panels). The corresponding brightfield images are shown in the third panels. Bar=20 μm
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References

    1. New DC, Wong J. The evidence for G-protein-coupled receptors and heterotrimeric G proteins in protozoa and ancestral metazoa. Biol Signals Recept. 1998;7(2):98–108. doi: 10.1159/000014535. - DOI - PubMed
    1. Urano D, Chen JG, Botella JR, Jones AM. Heterotrimeric G protein signalling in the plant kingdom. Open Biol. 2013;3:22. doi: 10.1098/rsob.120186. - DOI - PMC - PubMed
    1. Jose J, Choudhury SR. Heterotrimeric G-proteins mediated hormonal responses in plants. Cell Signal. 2020;76:109799. doi: 10.1016/j.cellsig.2020.109799. - DOI - PubMed
    1. Zhang H, Xie P, Xu X, Xie Q, Yu F. Heterotrimeric G protein signaling in plant biotic and abiotic stress response. Plant Biol. 2021;23:20–30. doi: 10.1111/plb.13241. - DOI - PubMed
    1. Gautam N, Downes GB, Yan K, Kisselev O. The G-protein βγ complex. Cell Signal. 1998;10(7):447–455. doi: 10.1016/S0898-6568(98)00006-0. - DOI - PubMed

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