In Arabidopsis thaliana,canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR(ARF)family that interact with auxin/indole acetic acid repressors(Aux/IAAs),whic...In Arabidopsis thaliana,canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR(ARF)family that interact with auxin/indole acetic acid repressors(Aux/IAAs),which themselves form co-receptor complexes with one of six TRANSPORT INHIBITOR*!/AUXIN-SIGNALLING F-BOX(TIR1/AFB)proteins.Different combinations of co-receptors drive specific sensing outputs,allowing auxin to control a myriad of processes.ARF6 and ARF8 are positive regulators of adventitious root initiation upstream of jasmonate,but the exact auxin co-receptor complexes controlling the transcriptional activity of these proteins has remained unknown.Here,using loss-of-function mutants we show that three Aux/IAA genes,IAA6,IAA9,and IAA17,act additively in the control of adventitious root(AR)initiation.These three IAA proteins interact with ARF6 and/or ARF8 and likely repress their activity in AR development.We show that TIR1 and AFB2 are positive regulators of AR formation and TIR1 plays a dual role in the control of jasmonic acid(JA)biosynthesis and conjugation,as several JA biosynthesis genes are up-regulated in the tir1-1 mutant.These results lead us to propose that in the presence of auxin,TIR1 and AFB2 form specific sensing complexes with IAA6,IAA9,and/or IAA17 to modulate JA homeostasis and control AR initiation.展开更多
The auxin receptor(TIR1/AFBs)family encodes the F-box protein subunit,which is involved in the formation of the E3 ubiquitin ligase SCFTIR1/AFBs complex,a key component of the auxin signaling pathway.However,there are...The auxin receptor(TIR1/AFBs)family encodes the F-box protein subunit,which is involved in the formation of the E3 ubiquitin ligase SCFTIR1/AFBs complex,a key component of the auxin signaling pathway.However,there are few studies on the auxin receptor family in apple(Malus×domestica).In this study,eight MdAFBs were identified,and phylogenetic analysis showed that they were classified into four groups and distributed on eight chromosomes.Herein,a comprehensive analysis of the MdAFB gene family was conducted to identify cis-acting elements,gene structures,protein structures,aligned sequences,conserved motifs,conserved amino acids,and the protein–protein interaction network.The results of yeast two-hybrid assays showed that MdAFB1 interacted with three auxin repressor proteins.The results of qRT-PCR showed that MdAFB1 responded to osmotic and salt stress.The overexpression of MdAFB1 increased osmotic and salt resistance in apple calli,and the ectopic expression of MdAFB1 enhanced osmotic and salt tolerance in Arabidopsis.This study provided a basis for the identification of auxin receptor genes in apple and their functions in mediating osmotic and salt stress.展开更多
Auxin,one of the first identified and most widely studied phytohormones,has been and will remain a hot topic in plant biology.After more than a century of passionate exploration,the mysteries of its synthesis,transpor...Auxin,one of the first identified and most widely studied phytohormones,has been and will remain a hot topic in plant biology.After more than a century of passionate exploration,the mysteries of its synthesis,transport,signaling,and metabolism have largely been unlocked.Due to the rapid development of new technologies,new methods,and new genetic materials,the study of auxin has entered the fast lane over the past 30 years.Here,we highlight advances in understanding auxin signaling,including auxin perception,rapid auxin responses,TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALING F-boxes(TIR1/AFBs)-mediated transcriptional and non-transcriptional branches,and the epigenetic regulation of auxin signaling.We also focus on feedback inhibition mechanisms that prevent the over-amplification of auxin signals.In addition,we cover the TRANSMEMBRANE KINASE-mediated non-canonical signaling,which converges with TIR1/AFBs-mediated transcriptional regulation to coordinate plant growth and development.The identification of additional auxin signaling components and their regulation will continue to open new avenues of research in this field,leading to an increasingly deeper,more comprehensive understanding of how auxin signals are interpreted at the cellular level to regulate plant growth and development.展开更多
文摘In Arabidopsis thaliana,canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR(ARF)family that interact with auxin/indole acetic acid repressors(Aux/IAAs),which themselves form co-receptor complexes with one of six TRANSPORT INHIBITOR*!/AUXIN-SIGNALLING F-BOX(TIR1/AFB)proteins.Different combinations of co-receptors drive specific sensing outputs,allowing auxin to control a myriad of processes.ARF6 and ARF8 are positive regulators of adventitious root initiation upstream of jasmonate,but the exact auxin co-receptor complexes controlling the transcriptional activity of these proteins has remained unknown.Here,using loss-of-function mutants we show that three Aux/IAA genes,IAA6,IAA9,and IAA17,act additively in the control of adventitious root(AR)initiation.These three IAA proteins interact with ARF6 and/or ARF8 and likely repress their activity in AR development.We show that TIR1 and AFB2 are positive regulators of AR formation and TIR1 plays a dual role in the control of jasmonic acid(JA)biosynthesis and conjugation,as several JA biosynthesis genes are up-regulated in the tir1-1 mutant.These results lead us to propose that in the presence of auxin,TIR1 and AFB2 form specific sensing complexes with IAA6,IAA9,and/or IAA17 to modulate JA homeostasis and control AR initiation.
基金supported by the National Natural Science Foundation of China(Grant Nos.32172538,31972378)China Agriculture Research System of MOF and MARA(Grant CARS-27).
文摘The auxin receptor(TIR1/AFBs)family encodes the F-box protein subunit,which is involved in the formation of the E3 ubiquitin ligase SCFTIR1/AFBs complex,a key component of the auxin signaling pathway.However,there are few studies on the auxin receptor family in apple(Malus×domestica).In this study,eight MdAFBs were identified,and phylogenetic analysis showed that they were classified into four groups and distributed on eight chromosomes.Herein,a comprehensive analysis of the MdAFB gene family was conducted to identify cis-acting elements,gene structures,protein structures,aligned sequences,conserved motifs,conserved amino acids,and the protein–protein interaction network.The results of yeast two-hybrid assays showed that MdAFB1 interacted with three auxin repressor proteins.The results of qRT-PCR showed that MdAFB1 responded to osmotic and salt stress.The overexpression of MdAFB1 increased osmotic and salt resistance in apple calli,and the ectopic expression of MdAFB1 enhanced osmotic and salt tolerance in Arabidopsis.This study provided a basis for the identification of auxin receptor genes in apple and their functions in mediating osmotic and salt stress.
基金financially supported by the National Natural Science Foundation of China and the Israel Science Foundation(NSFC-ISF32061143005)+2 种基金National Natural Science Foundation of China(32000225)Natural Science Foundation of Shandong Province(ZR2020QC036)China Postdoctoral Science Foundation(2020M682165)。
文摘Auxin,one of the first identified and most widely studied phytohormones,has been and will remain a hot topic in plant biology.After more than a century of passionate exploration,the mysteries of its synthesis,transport,signaling,and metabolism have largely been unlocked.Due to the rapid development of new technologies,new methods,and new genetic materials,the study of auxin has entered the fast lane over the past 30 years.Here,we highlight advances in understanding auxin signaling,including auxin perception,rapid auxin responses,TRANSPORT INHIBITOR RESPONSE 1 and AUXIN SIGNALING F-boxes(TIR1/AFBs)-mediated transcriptional and non-transcriptional branches,and the epigenetic regulation of auxin signaling.We also focus on feedback inhibition mechanisms that prevent the over-amplification of auxin signals.In addition,we cover the TRANSMEMBRANE KINASE-mediated non-canonical signaling,which converges with TIR1/AFBs-mediated transcriptional regulation to coordinate plant growth and development.The identification of additional auxin signaling components and their regulation will continue to open new avenues of research in this field,leading to an increasingly deeper,more comprehensive understanding of how auxin signals are interpreted at the cellular level to regulate plant growth and development.
