Molecular Cloning, Expression Analysis, and Functional Analysis of Nine <i>IbSWEETs</i> in <i>Ipomoea batatas</i> (L.) Lam
Sugar Will Eventually be Exported Transporter (<i>SWEET</i>) genes play an important regulatory role in plants’ growth and development, stress response, and sugar metabolism, but there are few reports on the role of SWEET proteins in sweet potato. In this study, nine <i>IbSWEET<...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-11-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/23/16615 |
| Summary: | Sugar Will Eventually be Exported Transporter (<i>SWEET</i>) genes play an important regulatory role in plants’ growth and development, stress response, and sugar metabolism, but there are few reports on the role of SWEET proteins in sweet potato. In this study, nine <i>IbSWEET</i> genes were obtained via PCR amplification from the cDNA of sweet potato. Phylogenetic analysis showed that nine IbSWEETs separately belong to four clades (Clade I~IV) and contain two MtN3/saliva domains or PQ-loop superfamily and six~seven transmembrane domains. Protein interaction prediction showed that seven SWEETs interact with other proteins, and SWEETs interact with each other (SWEET1 and SWEET12; SWEET2 and SWEET17) to form heterodimers. qRT-PCR analysis showed that <i>IbSWEETs</i> were tissue-specific, and <i>IbSWEET1b</i> was highly expressed during root growth and development. In addition to high expression in leaves, <i>IbSWEET15</i> was also highly expressed during root expansion, and <i>IbSWEET7</i>, <i>10a</i>, <i>10b</i>, and <i>12</i> showed higher expression in the leaves. The expression of <i>SWEETs</i> showed a significant positive/negative correlation with the content of soluble sugar and starch in storage roots. Under abiotic stress treatment, <i>IbSWEET7</i> showed a strong response to PEG treatment, while <i>IbSWEET10a</i>, <i>10b</i>, and <i>12</i> responded significantly to 4 °C treatment and, also, at 1 h after ABA, to NaCl treatment. A yeast mutant complementation assay showed that IbSWEET7 had fructose, mannose, and glucose transport activity; IbSWEET15 had glucose transport activity and weaker sucrose transport activity; and all nine IbSWEETs could transport 2-deoxyglucose. These results provide a basis for further elucidating the functions of <i>SWEET</i> genes and promoting molecular breeding in sweet potato. |
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| ISSN: | 1661-6596 1422-0067 |