AUTHOR=Li Wei , Sun Kuan , Ren Zhongying , Song Chengxiang , Pei Xiaoyu , Liu Yangai , Wang Zhenyu , He Kunlun , Zhang Fei , Zhou Xiaojian , Ma Xiongfeng , Yang Daigang 

TITLE=Molecular Evolution and Stress and Phytohormone Responsiveness of SUT Genes in Gossypium hirsutum

JOURNAL=Frontiers in Genetics

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2018.00494

DOI=10.3389/fgene.2018.00494

ISSN=1664-8021

ABSTRACT=<p>Sucrose transporters (SUTs) play key roles in allocating the translocation of assimilates from source to sink tissues. Although the characteristics and biological roles of <italic>SUTs</italic> have been intensively investigated in higher plants, this gene family has not been functionally characterized in cotton. In this study, we performed a comprehensive analysis of <italic>SUT</italic> genes in the tetraploid cotton <italic>Gossypium hirsutum</italic>. A total of 18 <italic>G. hirsutum SUT</italic> genes were identified and classified into three groups based on their evolutionary relationships. Up to eight <italic>SUT</italic> genes in <italic>G. hirsutum</italic> were placed in the dicot-specific SUT1 group, while four and six <italic>SUT</italic> genes were, respectively, clustered into SUT4 and SUT2 groups together with members from both dicot and monocot species. The <italic>G. hirsutum SUT</italic> genes within the same group displayed similar exon/intron characteristics, and homologous genes in <italic>G. hirsutum</italic> At and Dt subgenomes, <italic>G. arboreum</italic>, and <italic>G. raimondii</italic> exhibited one-to-one relationships. Additionally, the duplicated genes in the diploid and polyploid cotton species have evolved through purifying selection, suggesting the strong conservation of <italic>SUT</italic> loci in these species. Expression analysis in different tissues indicated that <italic>SUT</italic> genes might play significant roles in cotton fiber elongation. Moreover, analyses of <italic>cis</italic>-acting regulatory elements in promoter regions and expression profiling under different abiotic stress and exogenous phytohormone treatments implied that <italic>SUT</italic> genes, especially <italic>GhSUT6A/D</italic>, might participate in plant responses to diverse abiotic stresses and phytohormones. Our findings provide valuable information for future studies on the evolution and function of <italic>SUT</italic> genes in cotton.</p>