Genome-wide analysis and characterization of gene family reveal involvement in sucrose transportation in plants.

Sucrose is the main transported form of photosynthetic products. Sucrose transporter (SUT) participates in the translocation of sucrose from source to sink, which is important for the growth and development of plants. is an important economic crop in southwestern China because of its high growth rate, high fiber content, and dual usage for food and timber, but the mechanism of sucrose transportation in is unclear. In this study, a total of 12 transporter genes were determined in by whole-genome identification. , , and were homologs of rice , while was a homolog of , and these four genes were expressed in the leaf, internode, node, and bamboo shoots of . In addition, family genes were involved in photosynthetic product distribution, ABA/MeJA responses, and drought resistance, especially . The function of was then verified in . DfSUT4 was localized mainly in the leaf mesophyll and stem phloem of transgenic plant. The overexpression of gene in transgenic plant showed increases of photosynthetic rate, above-ground biomass, thousand grain weight, and cellulose content. Our findings altogether indicate that can be a candidate gene that can be involved in phloem sucrose transportation from the source leaves to the sink organs, phytohormone responses, abiotic stress, and fiber formation in plants, which is very important in the genetic improvement of and other crops.