The phytohormone jasmonates(JAs)regulate plant growth and defense responses.The reproductive organs of flowers are devastated by insect herbivores.However,the molecular mechanisms of floral defense remain largely unkn...The phytohormone jasmonates(JAs)regulate plant growth and defense responses.The reproductive organs of flowers are devastated by insect herbivores.However,the molecular mechanisms of floral defense remain largely unknown.Here,we found that the Arabidopsis JA receptor CORONATINE INSENSITIVE1(COI1)and its substrates JA ZIMdomain(JAZ)repressors,and the mediator subunit MEDIATOR25-based MED25-MYC-MYB(MMM)complexes,including MYC2/3/4/5 and MYB28/29/76,mediated floral defense against the insects Helicoverpa armigera,Spodoptera exigua,and Spodoptera frugiperda.The flower-specific IIIa b HLH factors ABORTED MICROSPORES(AMS)and DYSFUNCTIONAL TAPETUM 1(DYT1)were JAZ-interaction proteins.They interacted with members of the MMM complexes,inhibited the transcriptional activity of MYC2 and MYB28,and repressed floral defense against insects.AMS and DYT1 recruited the flower-specific MYB21/24,and these MYBs interacted with members of MMM complexes,inhibited the MYC2-MYB28 function,and suppressed floral defense against insects.Our study revealed that the JA-COI1-JAZ-MMM pathway mediated flower defense,and the AMS/DYT1-MYB21/24 module antagonized the MMM complexes to repress floral defense against insects.展开更多
In anther development, tapetal cells take part in complex processes, including endomitosis and apoptosis （programmed cell death）. The tapetum provides many of the proteins, lipids, polysaccharides and other molecule...In anther development, tapetal cells take part in complex processes, including endomitosis and apoptosis （programmed cell death）. The tapetum provides many of the proteins, lipids, polysaccharides and other molecules necessary for pollen development. Several transcription factors, including DYT1, TDF1, AMS, MS188 and MS1, have been reported to be essential for tapetum development and function in Arabidopsis thaliana. Here, we present a detailed cytological analysis of knockout mutants for these genes, along with an in situ RNA hybridization experiment and double mutant analysis showing that these transcription factors form a genetic pathway in tapetum development. DYT1, TDF1 and AMS function in early tapetum development, while MS188 and MS1 are important for late tapetum development. The genetic pathway revealed in this work facilitates further investigation of the function and molecular mechanisms of tapetum development in Arabidopsis.展开更多
基金supported by the National Natural Science Foundation of China(32270765)。
文摘The phytohormone jasmonates(JAs)regulate plant growth and defense responses.The reproductive organs of flowers are devastated by insect herbivores.However,the molecular mechanisms of floral defense remain largely unknown.Here,we found that the Arabidopsis JA receptor CORONATINE INSENSITIVE1(COI1)and its substrates JA ZIMdomain(JAZ)repressors,and the mediator subunit MEDIATOR25-based MED25-MYC-MYB(MMM)complexes,including MYC2/3/4/5 and MYB28/29/76,mediated floral defense against the insects Helicoverpa armigera,Spodoptera exigua,and Spodoptera frugiperda.The flower-specific IIIa b HLH factors ABORTED MICROSPORES(AMS)and DYSFUNCTIONAL TAPETUM 1(DYT1)were JAZ-interaction proteins.They interacted with members of the MMM complexes,inhibited the transcriptional activity of MYC2 and MYB28,and repressed floral defense against insects.AMS and DYT1 recruited the flower-specific MYB21/24,and these MYBs interacted with members of MMM complexes,inhibited the MYC2-MYB28 function,and suppressed floral defense against insects.Our study revealed that the JA-COI1-JAZ-MMM pathway mediated flower defense,and the AMS/DYT1-MYB21/24 module antagonized the MMM complexes to repress floral defense against insects.
基金The Science and Technology Commission of Shanghai Municipality(08PJ1405500)The National Natural Science Foundation of China(30870225)The Shanghai Municipality Education Commission 2009 Innovation Project of Science and Technology
基金supported by grants from the National Natural Science Foundation of China (30925007)Shanghai(11ZR1425800)the State Key Basic Research and Development Program of China (2007CB947600)
文摘In anther development, tapetal cells take part in complex processes, including endomitosis and apoptosis （programmed cell death）. The tapetum provides many of the proteins, lipids, polysaccharides and other molecules necessary for pollen development. Several transcription factors, including DYT1, TDF1, AMS, MS188 and MS1, have been reported to be essential for tapetum development and function in Arabidopsis thaliana. Here, we present a detailed cytological analysis of knockout mutants for these genes, along with an in situ RNA hybridization experiment and double mutant analysis showing that these transcription factors form a genetic pathway in tapetum development. DYT1, TDF1 and AMS function in early tapetum development, while MS188 and MS1 are important for late tapetum development. The genetic pathway revealed in this work facilitates further investigation of the function and molecular mechanisms of tapetum development in Arabidopsis.
