Casparian strip was first found in the endodermis ofprimary root by Robert Caspary,a German botanist[1].Itis frequently regarded as a specific structure of tracheo-phyta which appears a as lignified and suberized nano...Casparian strip was first found in the endodermis ofprimary root by Robert Caspary,a German botanist[1].Itis frequently regarded as a specific structure of tracheo-phyta which appears a as lignified and suberized nanowzone encircling the radial and transverse walle of the en-dodermal cells-2..Whether the foliar endodernis of gym-nosperm in partieular the coniferous species possessesCasparian strip or not still remains controversial[3-7].展开更多
Development of the functional endodermis of Arabidopsis thaliana roots is controlled, in part, by GRAS transcription factors, namely SHORT-ROOT （SHR）, SCARECROW （SCR）, and SCARECROW-LIKE 23 （SCL23）. Recently, it...Development of the functional endodermis of Arabidopsis thaliana roots is controlled, in part, by GRAS transcription factors, namely SHORT-ROOT （SHR）, SCARECROW （SCR）, and SCARECROW-LIKE 23 （SCL23）. Recently, it has been shown that the SHR-SCR-SCL23 regulatory module is also essential for spec- ification of the endodermis （known as the bundle sheath） in leaves. Nevertheless, compared with what is known about the role of the SHR-SCR-SCL23 regulatory network in roots, the molecular interactions of SHR, SCR, and SCL23 are much less understood in shoots. Here, we show that SHR forms protein com- plexes with SCL23 to regulate transcription of SCL23 in shoots, similar to the regulation mode of SCR expression. Our results indicate that SHR acts as master regulator to directly activate the expression of SCR and SCL23. In the SHR-SCR-SCL23 network, we found a previously uncharacterized negative feed- back loop whereby SCL23 modulates SHR levels. Through molecular, genetic, physiological, and morpho- logical analyses, we also reveal that the SHR-SCR-SCL23 module plays a key role in the formation of the endodermis （known as the starch sheath） in hypocotyls. Taken together, our results provide new insights into the regulatory role of the SHR-SCR-SCL23 network in the endodermis development in both roots and shoots.展开更多
Cell-to-cell communication is fundamental to multicellular life.In plants,plasmodesmata—cytoplasmic channels that connect adjacent cells—enable the transport of molecules between cells.In roots,such transport is tho...Cell-to-cell communication is fundamental to multicellular life.In plants,plasmodesmata—cytoplasmic channels that connect adjacent cells—enable the transport of molecules between cells.In roots,such transport is thought to play a central role in nutrient acquisition and delivery across the multiple cell layers.In this study,we demonstrate that plasmodesmatal transport persists in fully differentiated Arabidopsis roots,even after the establishment of apoplastic barriers such as Casparian strips and suberin lamellae in the endodermis.This persistence highlights plasmodesmata as a critical pathway for intercellular transport in mature roots.We also identify a developmental switch in plasmodesmatal function:while transport is bidirectional in young roots,it becomes unidirectional toward the vasculature in differentiated roots.Through a genetic screen,we identified mutants with impaired directionality that maintain persistent bidirectional transport.These mutants show enlarged plasmodesmatal apertures due to defects in pectin composition and cell wall organization,highlighting the critical role of pectin in plasmodesmatal formation and function.Our findings reveal that plasmodesmata-mediated transport is dynamically regulated during root development and provide new insights into the cellular mechanisms underlying intercellular communication in plants.展开更多
基金Supported by the National Natural Science Foundation of China(30070047)and the Chinese Academy of Sciences.
文摘Casparian strip was first found in the endodermis ofprimary root by Robert Caspary,a German botanist[1].Itis frequently regarded as a specific structure of tracheo-phyta which appears a as lignified and suberized nanowzone encircling the radial and transverse walle of the en-dodermal cells-2..Whether the foliar endodernis of gym-nosperm in partieular the coniferous species possessesCasparian strip or not still remains controversial[3-7].
文摘Development of the functional endodermis of Arabidopsis thaliana roots is controlled, in part, by GRAS transcription factors, namely SHORT-ROOT （SHR）, SCARECROW （SCR）, and SCARECROW-LIKE 23 （SCL23）. Recently, it has been shown that the SHR-SCR-SCL23 regulatory module is also essential for spec- ification of the endodermis （known as the bundle sheath） in leaves. Nevertheless, compared with what is known about the role of the SHR-SCR-SCL23 regulatory network in roots, the molecular interactions of SHR, SCR, and SCL23 are much less understood in shoots. Here, we show that SHR forms protein com- plexes with SCL23 to regulate transcription of SCL23 in shoots, similar to the regulation mode of SCR expression. Our results indicate that SHR acts as master regulator to directly activate the expression of SCR and SCL23. In the SHR-SCR-SCL23 network, we found a previously uncharacterized negative feed- back loop whereby SCL23 modulates SHR levels. Through molecular, genetic, physiological, and morpho- logical analyses, we also reveal that the SHR-SCR-SCL23 module plays a key role in the formation of the endodermis （known as the starch sheath） in hypocotyls. Taken together, our results provide new insights into the regulatory role of the SHR-SCR-SCL23 network in the endodermis development in both roots and shoots.
基金supported by iGe3 with a PhD salary award to L.J.,and by funding from the Sandoz Family Monique De Meuron philanthropic foundation's program for academic promotionby the Swiss National Science Foundation(grant 31003A_179159)to M.B.by the state of Geneva.
文摘Cell-to-cell communication is fundamental to multicellular life.In plants,plasmodesmata—cytoplasmic channels that connect adjacent cells—enable the transport of molecules between cells.In roots,such transport is thought to play a central role in nutrient acquisition and delivery across the multiple cell layers.In this study,we demonstrate that plasmodesmatal transport persists in fully differentiated Arabidopsis roots,even after the establishment of apoplastic barriers such as Casparian strips and suberin lamellae in the endodermis.This persistence highlights plasmodesmata as a critical pathway for intercellular transport in mature roots.We also identify a developmental switch in plasmodesmatal function:while transport is bidirectional in young roots,it becomes unidirectional toward the vasculature in differentiated roots.Through a genetic screen,we identified mutants with impaired directionality that maintain persistent bidirectional transport.These mutants show enlarged plasmodesmatal apertures due to defects in pectin composition and cell wall organization,highlighting the critical role of pectin in plasmodesmatal formation and function.Our findings reveal that plasmodesmata-mediated transport is dynamically regulated during root development and provide new insights into the cellular mechanisms underlying intercellular communication in plants.
