Isolation And Functional Analysis Of Rab8Family Genes In Nicotiana Benthamiana L.

Rab GTPases constitute a largest family of the Small GTPases, which play key roles inregulating vesicle trafficking. RabE (Rab8) proteins are related to the Golgi to PM-associatedRabs. Although the function of Rab8genes was investigated in animals, little is known abouttheir funcition in plants. In this study, we isolated NbRab8family genes in Nicotianabenthamiana L..The NbRab8family has six members (NbRab8-1~NbRab8-6).The nearly full-lengthcDNA of NbRab8is651bp in length.The deduced amino acid sequence of NbRab8genefamily contains217amino acid residues. Amino acid sequence comparison analysis showedthat NbRab8proteins have the conserved structural, including four guanine nucleotidebinding region and an effector molecule binding region. The phylogenetic analysis revealedthat NbRab8is closer to Arabidopsis RabE family. Real time quantitative PCR analysisshowed that NbRab8expression is constitutive, particularly in leaves.Subcellular localizationresults showed NbRab8located in the cell membrane and Golgi. TRV:NbRab8plants had thephenotypes such as dwarf, smaller and curled leaves, undeveloped roots, abnormal flowerwith abortive anthers and pistils. In addition, TRV:NbRab8plants were premature. The totallife span of the TRV:NbRab8plants was much shorter than that of control plants.In conclusion, NbRab8family involved in vesicle trafficking may play an important rolesin regulating tabacco development. This study provides new information on the function ofRab8in plants.