Genome-Wide Analysis of the <i>Rab</i> Gene Family in <i>Melilotus albus</i> Reveals Their Role in Salt Tolerance
<i>Melilotus albus</i> is a high-quality forage, due to its high protein content, and aboveground biomass and salt tolerance. Rab (Ras-related protein in the brain) proteins are the largest GTPase family which play a key role in intracellular membrane transport, and many <i>Rab<...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-12-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/1/126 |
| Summary: | <i>Melilotus albus</i> is a high-quality forage, due to its high protein content, and aboveground biomass and salt tolerance. Rab (Ras-related protein in the brain) proteins are the largest GTPase family which play a key role in intracellular membrane transport, and many <i>Rab</i> genes have been identified in eukaryotes. The growth and distribution of <i>M. albus</i> are severely hampered by soil salinization. However, little is known about candidate genes for salt tolerance in <i>M. albus</i>. In this study, 27 <i>Rab</i> family genes were identified for the first time from <i>M. albus</i>, and divided into eight groups (Groups A-H). The number of introns in <i>MaRabs</i> ranged from one to seven, with most genes containing one intron. In addition, most MaRab proteins showed similarities in motif composition. Phylogenetic analysis and structural-domain comparison indicated that <i>Rab</i> family genes were highly conserved in <i>M. albus</i>. Members of the MaRab gene family were distributed across all eight chromosomes, with the largest distribution on chromosome 1. Prediction of the protein interaction network showed that 24 Rab proteins exhibited protein–protein interactions. Analysis of the promoter <i>cis</i>-acting elements showed that <i>MaRab-</i>gene family members are extensively involved in abiotic stress responses. RNA-seq data analysis of the <i>MaRab-</i>gene-expression patterns suggested that the <i>Rab</i> gene family possesses differentially expressed members in five organs and under salt stress, drought stress, and ABA (Abscisic Acid) treatment. Differentially expressed genes under drought stress, salt stress and ABA stress were validated by quantitative real-time PCR. Furthermore, heterologous expression in yeast was used to characterize the functions of <i>MaRab1</i> and <i>MaRab17</i>, which were upregulated in reaction to salt stress. In summary, this study provided valuable information for further research into the molecular mechanism of the response of <i>M. albus</i> to saline stress, as well as the possibility of developing cultivars with high salt-resistance characteristics. |
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| ISSN: | 1661-6596 1422-0067 |