Genome-Wide Characterization and Analysis of the FH Gene Family in Medicago truncatula Under Abiotic Stresses

Abstract

Background: The formin family proteins play an important role in guiding the assembly and nucleation of linear actin and can promote the formation of actin filaments independently of the Arp2/3 complex. As a key protein that regulates the cytoskeleton and cell morphological structure, the formin gene family has been widely studied in plants such as Arabidopsis thaliana and rice.

Methods: In this study, we conducted comprehensive analyses, including phylogenetic tree construction, conserved motif identification, co-expression network analysis, and transcriptome data mining.

Results: A total of 18 MtFH gene family members were identified, and the distribution of these genes on chromosomes was not uniform. The phylogenetic tree divided the FH proteins of the four species into two major subgroups (Clade I and Clade II). Notably, Medicago truncatula and soybean exhibited closer phylogenetic relationships. The analysis of cis-acting elements revealed the potential regulatory role of the MtFH gene in light response, hormone response, and stress response. GO enrichment analysis again demonstrated the importance of FH for reactions such as actin nucleation. Expression profiling revealed that MtFH genes displayed significant transcriptional responsiveness to cold, drought, and salt stress conditions. And there was a temporal complementary relationship between the expression of some genes under stress. The protein interaction network indicated an interaction relationship between MtFH protein and profilin, etc. In addition, 22 miRNAs were screened as potential regulators of the MtFH gene at the post-transcriptional level.

Conclusions: In general, this study provides a basis for deepening the understanding of the physiological function of the MtFH gene and provides a reference gene for stress resistance breeding in agricultural production.

Keywords: Medicago truncatula; abiotic stress; formins.

Figure 1

The position distribution of MtFH gene family in chromosomes. The scale on the left is used to measure the length of chromosomes, and The density of genes in each chromosome is shown in blue and yellow colors.The yellow numbers to the left of each chromosome represent each chromosome.

Figure 2

Phylogenetic tree of FH among different species. ★ represents FH members of M. truncatula, represents FH members of Glycine max, represents FH members of Oryza sativa, represents FH members of Arabidopsis thaliana.

Figure 3

The evolutionary classification, conserved motifs, conserved domains, and gene structure of MtFH. (A) The phylogenetic tree of MtFH. (B) The conserved motif of MtFH. Each different colored rectangular box represents a conserved motif. (C) The conserved domain of MtFH protein. (D) The gene structure of MtFH. The yellow rectangles are exons, the green parts are the untranslated regions of the two segments, and the remaining black lines indicate introns.

Figure 4

Intraspecific collinearity analysis of M. truncatula. The yellow rectangle represents the chromosome, and the gene pairs with segment repetition are shown by the red line. The gray lines represent collinearity genes across the genome. The middle and inner rectangles are two different representations of gene density. The yellow numbers represent the each chromosome.

Figure 5

Collinearity analysis of FH genes between A. thaliana, O. sativa, P. sativum, Z. mays, G. max, and M. truncatula. The grey line is the collinearity between the genomes of the two species. The red line is the collinearity of FH gene.

Figure 6

(A) Distribution of cis-acting elements in each MtFH gene. (B) Quantitative distribution of each cis-acting element in MtFH gene and their functional classification.

Figure 7

Diagram of the predicted miRNA interaction network with MtFH gene. Both the color and size of the nodes are proportional to the Degree Centrality value; the larger the degree value, the darker the node color and the larger the node size.

Figure 8

GO enrichment plot of MtFH. The vertical axis is the GO annotation, the horizontal axis is the fold enrichment, the color of the dots symbolizes the significant degree of gene enrichment, and the size of the dots indicates the number of genes.

Figure 9

Heatmap of MtFH gene expression between six different tissues, the colors in the graph from green to red indicate small to large expression, and the genes were clustered according to their expression.

Figure 10

Heatmap of MtFH gene expression at 0 h, 2 h, 6 h, and 12 h under different stress conditions. (A) The expression profile of MtFH gene at four time points under cold stress. (B) The expression profile of MtFH at four time points under salt stress. (C) The expression profile of MtFH at four time points under drought stress.

Figure 11

The interaction network between MtFH protein and other proteins.