Characteristics and Expression Analysis of Invertase Gene Family in Common Wheat (Triticum aestivum L.)

Abstract

Invertase (INV) irreversibly catalyzes the conversion of sucrose into glucose and fructose, playing important role in plant development and stress tolerance. However, the functions of INV genes in wheat have been less studied. In this study, a total of 126 TaINV genes were identified using a genome-wide search method, which could be classified into five classes (TaCWI-α, TaCWI-β, TaCI-α, TaCI-β, and TaVI) based on phylogenetic relationship. A total of 101 TaINVs were collinear with their ancestors in the synteny analysis, and we speculated that polyploidy events were the main force in the expansion of the TaINV gene family. Compared with TaCI, TaCWI and TaVI are more similar in gene structure and protein properties. Transcriptome sequencing analysis showed that TaINVs expressed in multiple tissues with different expression levels. Among 19 tissue-specific expressed TaINVs, 12 TaINVs showed grain-specific expression pattern and might play an important role in wheat grain development. In addition, qRT-PCR results further confirmed that TaCWI50 and TaVI27 show different expression in grain weight NILs. Our results demonstrated that the high expression of TaCWI50 and TaVI27 may be associated with a larger TGW phenotype. This work provides the foundations for understanding the grain development mechanism.

Keywords: expression profiles; genome-wide; invertase; wheat.

Figure 1

Phylogenetic analysis of the invertase family members in A. thaliana, G. max, O. sativa, Z. may, T. urartu, Ae. tauschii, T. dicoccoides, and T. aestivum. The INVs from different species are labeled with different colors.

Figure 2

Synteny analysis of INV genes between wheat and two dicotyledons plants (A. thaliana, and G. max (A), two monocotyledons model plants (Z. mays, and O. sativa) (B), its relative ancestors (T. urartu, Ae. tauschii (C), and T. dicoccoides(D)). The gray line in the background indicates a collinear block, while the blue line highlights the isomorphic INV gene pair.

Figure 3

Chromosomal localization of TaINVs. Different groups of TaINVs are represented in different colors. Black represents CWI group, red represents VI group, and blue represents CI group. In addition, tandem repeat genes are connected with red brackets.

Figure 4

Phylogenetic relationship(A), cis-acting elements (B) and gene structure analysis (C) of TaINVs.

Figure 5

The motifs distribution of wheat Ac-INV proteins (B) were displayed according to phylogenetic relationships (A). The logos of ten motif were shown proportionally (C).

Figure 6

The motifs distribution of TaCI proteins (B) were displayed according to phylogenetic relationships (A). The logos of 10 motif were shown proportionally (C).

Figure 7

The expression profiles of TaINV genes involved in 5 tissues at different growth stages. The color scale of heatmap shows the level of gene expression.

Figure 8

Expression profiling of 9 TaINV genes in grains at D4, D7, and D10 stage between RHL81-L (L) and RHL81-S (S). Asterisks indicate significant differences between L and S at different time using two-tailed Student’s t-test: p < 0.01 (**), p < 0.05 (*).

Figure 9

Localization of fusion protein (pCaMV35S::TaCWI50-GFP). Scale bars are shown in the lower right corner of each image.