Genome-wide identification and bioinformatics analysis of the oil palm SAUR gene family

【Objective】To identify members of the small auxin-up RNA(SAUR)gene family in oil palm and analyze them by bioinformatics,so as to provide a foundation for the study of auxin the signal transduction mechanism in oil palm. 【Method】Homologs of Arabidopsis thaliana SAUR genes were identified in the whole genome database of oil palm,their protein sequences analyzed by CDD and Pfam database and sequences without conserved SAUR sequence motifs were eliminated. The SAUR gene family of oil palm was then analyzed by bioinformatics.【Result】A total of 40 oil palm SAUR genes(EgSAUR1-EgSAUR40) were obtained from the whole genome database,and 31 genes were unevenly distributed on the 14 chromosomes of oil palm,with 7 genes on chromosome 4,which contained the most number of genes. The two EgSAURs genes,EgSAUR14 and EgSAUR24,contained two exons,while the other 38 genes contained only one exon without an intron. 40 EgSAURs proteins were all localized in the nucleus. From predictions of the secondary structure of EgSAURs proteins,it was found that 40 EgSAUR proteins had four structural characteristics:α-helix,β-turn,random coil and extended chain. The proportions of random coil and α-helix were higher. 11 EgSAURs proteins were acidic and 29 EgSAURs proteins were alkaline. The 40 EgSAURs proteins were divided into four categories,of which the Ⅰ(except for EgSAUR27 protein),Ⅱ(except for EgSAUR3 and EgSAUR22),Ⅲ and Ⅳ proteins all have Auxin_inducible conservative domain. The oil palm SAUR gene family contained 10 conserved Motifs and Motif 2 existed in all gene members. The number of EgSAUR genes specifically expressed in flowers was the most(EgSAUR4,EgSAUR9,EgSAUR10,EgSAUR24,EgSAUR29,EgSAUR30,EgSAUR32 and EgSAUR33),followed by roots,stems and leaves. The number of genes specifically expressed in the mesocarp was the least.【Conclusion】Gene duplication and tissue expression specificity are the two characteristics of oil palm SAUR gene family members. It is speculated that SAUR gene plays a regulatory role in flower growth and development as well as pollination and fertilization in oil palm.