title: Cytokinins secreted by Agrobacterium promote transformation by repressing a plant myb transcription factor.
abstract: Agrobacterium-mediated transformation is the most widely used technique for generating transgenic plants. However, many crops remain recalcitrant. We found that an Arabidopsis myb family transcription factor (MTF1) inhibited plant transformation susceptibility. Mutating MTF1 increased attachment of several Agrobacterium strains to roots and increased both stable and transient transformation in both susceptible and transformation-resistant Arabidopsis ecotypes. Cytokinins from Agrobacterium tumefaciens decreased the expression of MTF1 through activation of the cytokinin response regulator ARR3. Mutating AHK3 and AHK4, genes that encode cytokinin-responsive kinases, increased the expression of MTF1 and impaired plant transformation. Mutant mtf1 plants also had increased expression of AT14A, which encodes a putative transmembrane receptor for cell adhesion molecules. Plants overexpressing AT14A exhibited increased susceptibility to transformation, whereas at14a mutant plants exhibited decreased attachment of bacteria to roots and decreased transformation, suggesting that AT14A may serve as an anchor point for Agrobacteria. Thus, by promoting bacterial attachment and transformation of resistant plants and increasing such processes in susceptible plants, treating roots with cytokinins may help engineer crops with improved features or yield.
authors.affiliation: 1Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Nagesh
authors.initials: N
authors.lastname: Sardesai
authors.forename: Lan-Ying
authors.initials: LY
authors.lastname: Lee
authors.forename: Huabang
authors.initials: H
authors.lastname: Chen
authors.forename: Hochul
authors.initials: H
authors.lastname: Yi
authors.forename: Gayla R
authors.initials: GR
authors.lastname: Olbricht
authors.forename: Alexandra
authors.initials: A
authors.lastname: Stirnberg
authors.forename: Jacob
authors.initials: J
authors.lastname: Jeffries
authors.forename: Kia
authors.initials: K
authors.lastname: Xiong
authors.forename: R W
authors.initials: RW
authors.lastname: Doerge
authors.forename: Stanton B
authors.initials: SB
authors.lastname: Gelvin
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism* / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D000071677:Histidine Kinase; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D059467:Transcriptome
chemical_list: C509519:ARR3 protein, Arabidopsis; D029681:Arabidopsis Proteins; C118912:At14a protein, Arabidopsis; D003583:Cytokinins; C549245:MYBC1 protein, Arabidopsis; D011956:Receptors, Cell Surface; D014157:Transcription Factors; D011494:Protein Kinases; D000071677:Histidine Kinase; C000605493:AHK3 protein, Arabidopsis; C421783:WOL protein, Arabidopsis