【摘 要】
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The signaling pathway of the gaseous hormone ethylene is involved in plant reproduction,growth,devel-opment,and stress responses.During reproduction,the two synergid cells of the angiosperm female gametophyte both undergo programmed cell death(PCD)/degene
【机 构】
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State Key Laboratory for Protein and Plant Gene Research,Peking-Tsinghua Center for Life Sciences at
论文部分内容阅读
The signaling pathway of the gaseous hormone ethylene is involved in plant reproduction,growth,devel-opment,and stress responses.During reproduction,the two synergid cells of the angiosperm female gametophyte both undergo programmed cell death(PCD)/degeneration but in a different manner:PCD/degeneration of one synergid facilitates pollen tube rupture and thereby the release of sperm cells,while PCD/degeneration of the other synergid blocks supernumerary pollen tubes.Ethylene signaling was postu-lated to participate in some of the synergid cell functions,such as pollen tube attraction and the induction of PCD/degeneration.However,ethylene-mediated induction of synergid PCD/degeneration and the role of ethylene itself have not been firmly established.Here,we employed the CRISPR/Cas9 technology to knock out the five ethylene-biosynthesis 1-aminocyclopropane-1-carboxylic acid oxidase(ACO)genes and created Arabidopsis mutants free of ethylene production.The ethylene-free mutant plants showed normal triple responses when treated with ethylene rather than 1-aminocyclopropane-1-carboxylic acid,but had increased lateral root density and enlarged petal sizes,which are typical phenotypes of mutants defective in ethylene signaling.Using these ethylene-free plants,we further demonstrated that production of ethylene is not necessarily required to trigger PCD/degeneration of the two synergid cells,but certain com-ponents of ethylene signaling including transcription factors ETHYLENE-INSENSITIVE 3(EIN3)and EIN3-LIKE 1(EIL1)are necessary for the death of the persistent synergid cell.
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