Table 1. Arabidopsis mutations of genes with microtubule-associated functions. Only mutants for which the genetic lesion has been reported are presented. This list contains sensu strictu MAP mutants, mutants of the tubulin folding machinery as well as further mutants for which distinctive microtubule-related phenotypes have been reported. Homology AGI number Mutant angustifolia1 similar to CtBP- an1 Bars At1g01510 Main morphological and sub- Miscellaneous Reference cellular phenotype - reduced trichome branching (Kim et al., 2002) - microtubule density (Folkers et al., - elongated leaves 2002) - microtubule orientation arl2 ARF-like (titan5, GTPase family, hallimasch) tubulin folding armadillo-repeat kinesin (plant- containing specific class) At2g18390 - mutants arrest during (Steinborn et al., embryogenesis At1g01950 2002) - helical root growth (Sakai et al., 2008) kinesin ark2 atk1 kinesin 14 At4g21270 class - atk1-1 mutant male meiotic (Chen et al., spindles (metaphase1) were 2002; Marcus et broad, unfocused and multi- al., 2003) axial atk5 kinesin 14 At4g05190 class - plants appear (Ambrose et al., morphologically normal 2005; Ambrose - involved in early mitotic and Cyr, 2007) spindle formation champignon tubulin-folding (titan1) co-factor D clasp-1 CLASP At3g60740 - mutants arrest during (Steinborn et al., embryogenesis At2g20190 homologue 2002) - plants are dwarfed (Ambrose et al., - less populated cortical 2007; Kirik et al., microtubules array 2007) - mitotic arrays are aberrant eb1-a End Binding1 At3g47690 - helical growth double and (Bisgrove et al., eb1-b homologue At5g62500 - some alleles oryzalin triple mutants 2008) eb1-c At5g67270 hypersensitive reveal phenotype endosperm plant MAP At2g44190 defective1 - endosperm does not (Pignocchi et al., cellularize ede1 2009) - cytokinesis defects in embryo fass phosphatase fs1 PP2A (ton2) regulatory and cortical microtubules are Camilleri et al., subunit B” misaligned 2002) fragile fiber1 kinesin 4 class At5g18580 At5g47820 fra1 - no division plane alignment (Torres-Ruiz and - lacks pre-prophase bands Jurgens, 1994; - reduced mechanical (Zhong et al., strength of fibers 2002; Zhou et al., - abnormal orientation of 2007) cellulose microfibrils fragile fiber2 katanin p60 fra2 subunit At1g80350 (bot1, lue1, erh3) - stunted growth (Bichet et al., - ectopic root hairs 2001; Burk et al., - delayed establishment of 2001; Webb et the cortical microtubule array al., 2002; Bouquin et al., 2003) hinkel kinesin 14 (nack1) class At1g18370 - cytokinesis defects (Nishihama et al., - phragmoplast microtubules 2002; Strompen do not re-organize ibo1 NIMA-related (nek6) protein kinase At3g44200 - epidermal outgrowth et al., 2002) GFP fusions (Motose et al., label 2008; Sakai et microtubules; al., 2008) interaction with ARK kinesins. kiesel tubulin-folding kis co-factor A At2g30410 - shape defect in trichomes (Kirik et al., - cell defect in etiolated 2002b; Steinborn hypocotyls et al., 2002) - microtubule orientation abnormal kinesin13a kinesin 13 At3g16630 class map18 microtubule binding motif of MAP1B - overbranched trichome (Lu et al., 2005) - Golgi stacks clustered At5g44610 - cell shape defects based on RNAi (Wang et al., - microtubule orientation data 2007) defective map70-5 plant MAP At4g17220 - reduced inflorescence growth based on RNAi (Korolev et al., data 2007) temperature- (Whittington et - helical organ growth in overexpressors microtubule XMAP215 / organization1 TOGp swelling, stunted organs and sensitive alleles al., 2001; Twell et mor1 homologue cytokinesis defects present al., 2002) At2g35630 (gem1) - helical organ growth, cell - reduced microtubule length morphogenesis kinesin (plant- of root-hairs specific class) At3g54870 - split root hairs (Jones et al., - root hair microtubules with 2006; Yang et al., mrh2 ectopic localization in 2007; Sakai et (ark1) endoplasm al., 2008) nedd1 WD40 repeat At5g05970 protein pfifferling tubulin-folding tubulin folding plp3 (Zeng et al., development At1g71440 co-factor E phosducin 3 - mitotic defects during pollen 2009) - mutants arrest during (Steinborn et al., embryogenesis At3g50960 At5g66410 - disoriented cell growth and cytokinesis defects - disrupted microtubule arrays 2002) includes RNAi (Castellano and data, double Sablowski, 2008) knock-down reveals phenotype phragmoplast- kinesin 12 At3g17360 orienting class At3g19050 kinesin kinesin 12 At4g14150 associated class At3g23670 pakrp2 double mutants (Müller et al., reveal 2006) phenotype and misplaced cell walls phramoplast- pakrp1 and cytokinesis - misoriented mitotic arrays pok1 and pok2 kinesin - abnormal plane of - defects in the first post- double mutants meiotic division of the male reveal gametophyte1 phenotype - phragmoplasts of the microspore become disorganized (Lee et al., 2007) pleiade PRC1 / Ase1 / (map65-3) MAP65 At5g51600 homologue - cytokinesis defects in roots (Müller et al., - the cytokinetic phragmoplast 2002; Müller et is distorted al., 2004; Caillaud et al., 2008) porcino tubulin-folding por co-factor C At4g39920 - mutants arrest early during (Kirik et al., embryogenesis 2002a; Steinborn - strong mutants have no et al., 2002) detectable microtubules propyzamide- similar to hypersensitive1 MAPK phs1 phosphatase prefoldin6 prefoldin At5g23720 At1g29990 homologue - helical growth dominant- (Naoi and - cortical microtubules less negative allele, Hashimoto, 2004) ordered and more knock-out is fragmented embryo-lethal - shorter roots and etiolated (Gu et al., 2008) hypocotyls ran-gap mutants RanGAP At3g63130 - oblique cell walls in roots based on a rg1 homologue At5g19320 - cell wall stubs combination of rg2 (Xu et al., 2008) RNAi with TDNA insertion root swelling7 kinesin 5 class At2g28620 rsw7 - swollen roots temperature- (Bannigan et al., - cortical and spindle sensitive allele 2007) microtubules misoriented rop-interacting1 CRIB motif At2g33460 ric1 - misformed leaf epidermal (Fu et al., 2005) cells - fewer, shorter and less organized microtubules runkel kinase domain ruk and HEAT organization and arrested (emb3013) repeats cell plate expansion spira1-like 2 plant MAP At5g18700 At1g69230 - abnormal phragmoplast - enhanced helical organ spira1-like 3 At3g02180 growth when analyzed in spira1-like 4 At5g15600 spr1 background (Krupnova et al., 2009) (Nakajima et al., 2006) spiral1 plant MAP At2g03680 spr1 - helical growth and swollen cells (sku6) - helical microtubule arrays (Furutani et al., 2000; Nakajima et al., 2004; Sedbrook et al., 2004) spiral3 GCP2 spr3 homologue through recessive missense with grip motif mutation At5g17410 (SPC98-like) - right-handed helical growth (Nakamura and Hashimoto, 2009) - knock-outs have gametophytic defects stud1 kinesin 14 std1 class At3g43210 (tetraspore, (Hülskamp et al., abnormal pollen shape 1997; Spielman - male meiotic microtubule nack2) tangled1 - meiosis defects lead to array fails to form plant MAP At3g05330 tan1 - abnormal plane of cytokinesis et al., 1997; Yang et al., 2003) (Walker et al., 2007) - PPB alignment and phragmoplast attraction impaired tonneau1 LisH domain ton1 TOF motif At3g55000 - no division plane alignment (Traas et al., - no PPB formed 1995; Nacry et PLL motif al., 1998; Azimzadeh et al., 2008) tortifolia1 plant MAP At4g27060 tor1 (spr2, cn) - helical organ growth (Bürger, 1971; - cortical microtubules Buschmann et misaligned and later helical - altered microtubule dynamics tortifolia1-like (spr2-like) plant MAP At1g50890 - enhances twisting in tor1 background al., 2004; Shoji et al., 2004; Yao et al., 2008) (Yao et al., 2008) tua2 -tubulin At1g50010 tua3 GTP binding At5g19770 tua4 At1g04820 tua5 At5g19780 tua6 At4g14960 (lefty1+2, tor2) tua6cys213 is a (Bao et al., 2001; helical microtubule arrays in temperature Thitamadee et dominant-negative mutants sensitive allele; al., 2002; Ishida antisense data and Hashimoto, available. 2007; Ishida et - helical organ twisting and - altered microtubule dynamics in helical growth background al., 2007; - stunted growth in -tubulin Buschmann et al., 2009) antisense plants tub1 -tubulin At1g75780 - helical organ twisting dominant- (Ishida et al., tub2 GTPase At5g62690 - helical microtubule arrays negative tubulin 2007) tub3 At5g62700 tub4 At5g44340 mutations tug1 -tubulin tug2 At3g61650 At5g05620 - gametophytic or seedling lethal - aberrant cytokinetic microtubule arrays double mutants (Binarova et al., reveal 2006; Pastuglia phenotype, et al., 2006) RNAi data also available ungud9 plant MAP At2g34680 (air9) - embryo lethal and (Lalanne et al., gametophyte defective 2004; Buschmann et al., 2006; Buschmann et al., 2007) wave- TPX2 domain dampened2 homology At5g28646 - helical growth and impaired root waving wvd2 overexpression (Yuen et al., and RNAi 2003; Perrin et - helical microtubule arrays wave- TPX2 domain dampened-like homology At3g04630 - helical growth and impaired root waving al., 2007) overexpression (Yuen et al., and RNAi 2003; Perrin et wdl1 al., 2007) zwichel Ca2+ / zwi (kcbp) - fewer trichome branches zwi mutants (Oppenheimer et calmodulin – and impaired branch may be al., 1997; regulated class elongation hypomorphic Krishnakumar 14 kinesin At5g65930 and Oppenheimer, 1999; Reddy et al., 2004) Supplemental References Ambrose, J.C., and Cyr, R. 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