During the terminal stage of stomatal development,the R2R3-MYB transcription factors FOUR LIPS(FLP/MYB124) and MYB88 limit guard mother cell division by repressing the transcript levels of multiple cell-cycle genes.In Arabidopsis thaliana possessing the weak allele flp-1,an extra guard mother cell di-vision results in two stomata having direct contact.Here,we identified an ethylmethane sulfonate-mutagenized mutant,flp-1 xs01c,which exhibited more severe defects than fip-1 alone,producing giant tumor-like cell clusters.XS01C,encoding F-BOX STRESS-INDUCED 4 (FBS4),is preferentially ex-pressed in epidermal stomatal precursor cells.Overexpressing FBS4 rescued the defective stomatal phenotypes of flp-1 xs01c and flp-1 mutants.The deletion or substitution of a conserved residue (Pro-line166) within the F-box domain of FBS4 abolished or reduced,respectively,its interaction with Arabi-dopsis Skp1-Like1 (ASK1),the core subunit of the Skp1/Cullin/F-box E3 ubiquitin ligase complex.Fur-thermore,the FBS4 protein physically interacted with CYCA2;3 and induced its degradation through the ubiquitin-26S proteasome pathway.Thus,in addition to the known transcriptional pathway,the terminal symmetric division in stomatal development is en sured at the post-translational level,such as through the ubiquitination of target proteins recognized by the stomatal lineage F-box protein FBS4.

Yi Li;Shan Xue;Qixiumei He;Junxue Wang;Lingling Zhu;Junjie Zou;Jie Zhang;Chaoran Zuo;Zhibin Fan;Junling Yue;Chunxia Zhang;Kezhen Yang;Jie Le

Key Laboratory of Plant Molecular Physiology,CAS Center for Excellence in Molecular Plant Sciences,Institute of Botany,The Chinese Academy of Sciences,Beijing 100093,China;University of Chinese Academy of Sciences,Beijing 100049,China;The Institute of Scientific and Technical Information of China,Beijing 100038,China;Wenbo School,Jinan 250100,China;Biotechnology Research Institute,Chinese Academy of Agricultural Sciences,Beijing 100081,China

植物学报（英文版）

[1]Yi Li;Shan Xue;Qixiumei He;Junxue Wang;Lingling Zhu;Junjie Zou;Jie Zhang;Chaoran Zuo;Zhibin Fan;Junling Yue;Chunxia Zhang;Kezhen Yang;Jie Le-.Arabidopsis F-BOX STRESS INDUCED 4 is required to repress excessive divisions in stomatal development)[J].植物学报（英文版）,2022(01):56-72

MYB124,MYB88,flp,mutagenized,xs01c,fip,XS01C,FBS4,line166,dopsis,Like1,CYCA2

Arabidopsis,BOX,STRESS,INDUCED,required,excessive,divisions,stomatal,development,During,terminal,stage,R2R3,factors,FOUR,LIPS,FLP,limit,guard,mother,by,repressing,levels,multiple,cycle,genes,In,thaliana,possessing,weak,allele,extra,results,two,having,direct,contact,Here,identified,ethylmethane,sulfonate,which,exhibited,severe,defects,alone,producing,giant,tumor,like,clusters,encoding,preferentially,pressed,epidermal,precursor,cells,Overexpressing,rescued,defective,phenotypes,mutants,deletion,substitution,conserved,residue,Pro,within,box,domain,abolished,reduced,respectively,its,interaction,Skp1,ASK1,core,subunit,Cullin,E3,ligase,complex,Fur,thermore,physically,interacted,induced,degradation,through,26S,proteasome,pathway,Thus,addition,known,transcriptional,symmetric,sured,post,translational,such,ubiquitination,target,proteins,recognized,lineage

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