title: Genome-wide analysis and expression profiling of the PIN auxin transporter gene family in soybean (Glycine max).
abstract: BACKGROUND
  The plant phytohormone auxin controls many aspects of plant growth and development, which largely depends on its uneven distribution in plant tissues. Transmembrane proteins of the PIN family are auxin efflux facilitators. They play a key role in polar auxin transport and are associated with auxin asymmetrical distribution in plants. PIN genes have been characterized in several plant species, while comprehensive analysis of this gene family in soybean has not been reported yet.
  
  
  RESULTS
  In this study, twenty-three members of the PIN gene family were identified in the soybean genome through homology searches. Analysis of chromosome distribution and phylogenetic relationships of the soybean PIN genes indicated nine pairs of duplicated genes and a legume specific subfamily. Organ/tissue expression patterns and promoter activity assays of the soybean PINs suggested redundant functions for most duplicated genes and complementary and tissue-specific functions during development for non-duplicated genes. The soybean PIN genes were differentially regulated by various abiotic stresses and phytohormone stimuli, implying crosstalk between auxin and abiotic stress signaling pathways. This was further supported by the altered auxin distribution under these conditions as revealed by DR5::GUS transgenic soybean hairy root. Our data indicates that GmPIN9, a legume-specific PIN gene, which was responsive to several abiotic stresses, might play a role in auxin re-distribution in soybean root under abiotic stress conditions.
  
  
  CONCLUSIONS
  This study provided the first comprehensive analysis of the soybean PIN gene family. Information on phylogenetic relationships, gene structure, protein profiles and expression profiles of the soybean PIN genes in different tissues and under various abiotic stress treatments helps to identity candidates with potential roles in specific developmental processes and/or environmental stress conditions. Our study advances our understanding of plant responses to abiotic stresses and serves as a basis for uncovering the biological role of PIN genes in soybean development and adaption to adverse environments.
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA. wangyq@missouri.edu.
authors.forename: Yongqin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA. chaic@missouri.edu.
authors.forename: Chenglin
authors.initials: C
authors.lastname: Chai
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA. valliyodanb@missouri.edu.
authors.forename: Babu
authors.initials: B
authors.lastname: Valliyodan
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA. clm3n7@mail.missouri.edu.
authors.forename: Christine
authors.initials: C
authors.lastname: Maupin
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA. bsahf7@mail.missouri.edu.
authors.forename: Brad
authors.initials: B
authors.lastname: Annen
authors.affiliation: Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, 65211, USA. nguyenhenry@missouri.edu.
authors.forename: Henry T
authors.initials: HT
authors.lastname: Nguyen
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D032461:Chromosomes, Plant / Q000235:genetics; D055864:Droughts; D020869:Gene Expression Profiling; D023281:Genomics; D007210:Indoleacetic Acids / Q000378:metabolism* / Q000494:pharmacology; D009928:Organ Specificity; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012492:Salts / Q000494:pharmacology; D013025:Glycine max / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; D012492:Salts; D000040:Abscisic Acid