Brassinosteroids （BRs） are natural plant hormones critical for growth and development. BR-deficient or signaling mutants show significantly shortened root phenotypes. But for a long time, it was thought that these p...Brassinosteroids （BRs） are natural plant hormones critical for growth and development. BR-deficient or signaling mutants show significantly shortened root phenotypes. But for a long time, it was thought that these phenotypes were solely caused by reduced root cell elongation in the mutants. Functions of BRs in regulating root development have been largely neglected. Recent detailed analyses, however, revealed that BRs are not only involved in root cell elongation but are also involved in many aspects of root development, such as maintenance of meristem size, root hair formation, lateral root initiation, gravitropic response, mycorrhiza formation, and nodulation in legume species. In this review, current findings on the functions of BRs in mediating root growth, development, and symbiosis are discussed.展开更多
Among the five members of AUX1/LAX genes coding for auxin carriers in rice,only OsAUX1 and OsAUX3 have been reported.To understand the function of the other AUX1/LAX genes,two independent alleles of osaux4 mutants,osa...Among the five members of AUX1/LAX genes coding for auxin carriers in rice,only OsAUX1 and OsAUX3 have been reported.To understand the function of the other AUX1/LAX genes,two independent alleles of osaux4 mutants,osaux4-1 and osaux4-2,were constructed using the CRISPR/Cas9 editing system.Homozygous osaux4-1 or osaux4-2 exhibited shorter primary root(PR)and longer root hair(RH)compared to the wild-type Dongjin(WT/DJ),and lost response to indoleacetic acid(IAA)treatment.OsAUX4 is intensively expressed in roots and localized on the plasma membrane,suggesting that OsAUX4 might function in the regulation of root development.The decreased meristem cell division activity and the downregulated expression of cell cycle genes in root apices of osaux4 mutants supported the hypothesis that OsAUX4 positively regulates PR elongation.OsAUX4 is expressed in RH,and osaux4 mutants showing longer RH compared to WT/DJ implies that OsAUX4 negatively regulates RH development.Furthermore,osaux4 mutants are insensitive to Pi starvation(-Pi)and OsAUX4 effects on the-Pi response is associated with altered expression levels of Pi starvation-regulated genes,and auxin distribution/contents.This study revealed that OsAUX4 not only regulates PR and RH development but also plays a regulatory role in crosstalk between auxin and-Pi signaling.展开更多
The phytohormone auxin plays a pivotal role in governing plant growth and development.Although the TRANSPORT INHIBITOR RESPONSE1/AUXIN SIGNALING F-BOX(TIR1/AFB)receptors function in both the nucleus and cytoplasm,the ...The phytohormone auxin plays a pivotal role in governing plant growth and development.Although the TRANSPORT INHIBITOR RESPONSE1/AUXIN SIGNALING F-BOX(TIR1/AFB)receptors function in both the nucleus and cytoplasm,the mechanism governing the distribution of TIR1/AFBs between these cellular compartments remains unknown.In this study,we demonstrate that auxin-mediated oxidation of TIR1/AFB2 is essential for their targeting to the nucleus.We showed that small active molecules,reactive oxygen species(ROS)and nitric oxide(NO),are indispensable for the nucleo-cytoplasmic distribution of TIR1/AFB2 in trichoblasts and root hairs.Further studies revealed that this process is regulated by the FERONIA receptor kinase–NADPH oxidase signaling pathway.Interestingly,ROS and NO initiate oxidative modifications in TIR1C140/516 and AFB2C135/511,facilitating their subsequent nuclear import.The oxidized forms of TIR1C140/516 and AFB2C135/511 play a crucial role in enhancing the function of TIR1 and AFB2 in transcriptional auxin responses.Collectively,our study reveals a novel mechanism by which auxin stimulates the transport of TIR1/AFB2 from the cytoplasm to the nucleus,orchestrated by the FERONIA–ROS signaling pathway.展开更多
Root hairs are tubular outgrowths specifically differentiated from epidermal cells in a differentiation zone. The formation of root hairs greatly increases the surface area of a root and maximizes its ability to absor...Root hairs are tubular outgrowths specifically differentiated from epidermal cells in a differentiation zone. The formation of root hairs greatly increases the surface area of a root and maximizes its ability to absorb water and inorganic nutrients essential for plant growth and development. Root hair development is strictly regulated by intracellular and intercellular signal communications. Cell surface-localized receptor-like protein kinases （P, LKs） have been shown to be important components in these cellular processes, tn this review, the functions of a number of key P, LKs in regulating Arabidopsis root hair development are discussed, especially those involved in root epidermal cell fate determination and root hair tip growth.展开更多
Emerging evidence has demonstrated that ROP GTPases play important roles in symbiosis,but the molecular mechanisms on their regulation in symbiosis are largely unknown.In this study,we showed that MtROP8 is involved i...Emerging evidence has demonstrated that ROP GTPases play important roles in symbiosis,but the molecular mechanisms on their regulation in symbiosis are largely unknown.In this study,we showed that MtROP8 is involved in the symbiotic interaction between Medicago truncatula and Sinorhizobium meliloti.Expression analyses showed that MtROP8 was down-regulated in the early infected roots,but significantly up-regulated in nodules compared to the roots.Phenotypic analysis of RNA interference(RNAi)-mediated silencing of MtROP8 revealed that knock-down of MtROP8 expression resulted in various developmental defects of root hairs,including branched hairs,short bulbous root hairs,and even root hairs with apparent swollen bases,which were caused by the modification of the distribution and the levels of reactive oxygen species(ROS).Moreover,infection events were increased in transgenic roots harboring the MtROP8 RNAi construct in response to S.meliloti inoculation,concomitant with enhanced nodulation.These results indicate that MtROP8participates in root hair development and the establishmentof the symbiotic interaction by regulating ROS production and distribution.展开更多
文摘Brassinosteroids （BRs） are natural plant hormones critical for growth and development. BR-deficient or signaling mutants show significantly shortened root phenotypes. But for a long time, it was thought that these phenotypes were solely caused by reduced root cell elongation in the mutants. Functions of BRs in regulating root development have been largely neglected. Recent detailed analyses, however, revealed that BRs are not only involved in root cell elongation but are also involved in many aspects of root development, such as maintenance of meristem size, root hair formation, lateral root initiation, gravitropic response, mycorrhiza formation, and nodulation in legume species. In this review, current findings on the functions of BRs in mediating root growth, development, and symbiosis are discussed.
基金This project was funded by grants from the National Key Research and Development Program of China(2016YFD0100400)the Zhejiang Provincial Natural Science Foundation of China(LZ19C020001)the National Natural Science Foundation of China(32060451).
文摘Among the five members of AUX1/LAX genes coding for auxin carriers in rice,only OsAUX1 and OsAUX3 have been reported.To understand the function of the other AUX1/LAX genes,two independent alleles of osaux4 mutants,osaux4-1 and osaux4-2,were constructed using the CRISPR/Cas9 editing system.Homozygous osaux4-1 or osaux4-2 exhibited shorter primary root(PR)and longer root hair(RH)compared to the wild-type Dongjin(WT/DJ),and lost response to indoleacetic acid(IAA)treatment.OsAUX4 is intensively expressed in roots and localized on the plasma membrane,suggesting that OsAUX4 might function in the regulation of root development.The decreased meristem cell division activity and the downregulated expression of cell cycle genes in root apices of osaux4 mutants supported the hypothesis that OsAUX4 positively regulates PR elongation.OsAUX4 is expressed in RH,and osaux4 mutants showing longer RH compared to WT/DJ implies that OsAUX4 negatively regulates RH development.Furthermore,osaux4 mutants are insensitive to Pi starvation(-Pi)and OsAUX4 effects on the-Pi response is associated with altered expression levels of Pi starvation-regulated genes,and auxin distribution/contents.This study revealed that OsAUX4 not only regulates PR and RH development but also plays a regulatory role in crosstalk between auxin and-Pi signaling.
基金supported by grants from the National Natural Science Foundation of China(32230009,31770307,31972863)the Science and Technology Innovation Plan Of Shanghai Science and Technology Commission(20ZR1416500).
文摘The phytohormone auxin plays a pivotal role in governing plant growth and development.Although the TRANSPORT INHIBITOR RESPONSE1/AUXIN SIGNALING F-BOX(TIR1/AFB)receptors function in both the nucleus and cytoplasm,the mechanism governing the distribution of TIR1/AFBs between these cellular compartments remains unknown.In this study,we demonstrate that auxin-mediated oxidation of TIR1/AFB2 is essential for their targeting to the nucleus.We showed that small active molecules,reactive oxygen species(ROS)and nitric oxide(NO),are indispensable for the nucleo-cytoplasmic distribution of TIR1/AFB2 in trichoblasts and root hairs.Further studies revealed that this process is regulated by the FERONIA receptor kinase–NADPH oxidase signaling pathway.Interestingly,ROS and NO initiate oxidative modifications in TIR1C140/516 and AFB2C135/511,facilitating their subsequent nuclear import.The oxidized forms of TIR1C140/516 and AFB2C135/511 play a crucial role in enhancing the function of TIR1 and AFB2 in transcriptional auxin responses.Collectively,our study reveals a novel mechanism by which auxin stimulates the transport of TIR1/AFB2 from the cytoplasm to the nucleus,orchestrated by the FERONIA–ROS signaling pathway.
基金supported by grants from the National Natural Science Foundation of China(31700245 to Zhuoyun Wei,31720103902,31470380,and 31530005 to Jia Li)the China Postdoctoral Science Foundation(2018T111116 and 2016M602889 to Zhuoyun Wei)
文摘Root hairs are tubular outgrowths specifically differentiated from epidermal cells in a differentiation zone. The formation of root hairs greatly increases the surface area of a root and maximizes its ability to absorb water and inorganic nutrients essential for plant growth and development. Root hair development is strictly regulated by intracellular and intercellular signal communications. Cell surface-localized receptor-like protein kinases （P, LKs） have been shown to be important components in these cellular processes, tn this review, the functions of a number of key P, LKs in regulating Arabidopsis root hair development are discussed, especially those involved in root epidermal cell fate determination and root hair tip growth.
基金supported by the National Basic Research Program of China(2010CB126501)the National Natural Science Foundation of China(31071065 and 31270292)
文摘Emerging evidence has demonstrated that ROP GTPases play important roles in symbiosis,but the molecular mechanisms on their regulation in symbiosis are largely unknown.In this study,we showed that MtROP8 is involved in the symbiotic interaction between Medicago truncatula and Sinorhizobium meliloti.Expression analyses showed that MtROP8 was down-regulated in the early infected roots,but significantly up-regulated in nodules compared to the roots.Phenotypic analysis of RNA interference(RNAi)-mediated silencing of MtROP8 revealed that knock-down of MtROP8 expression resulted in various developmental defects of root hairs,including branched hairs,short bulbous root hairs,and even root hairs with apparent swollen bases,which were caused by the modification of the distribution and the levels of reactive oxygen species(ROS).Moreover,infection events were increased in transgenic roots harboring the MtROP8 RNAi construct in response to S.meliloti inoculation,concomitant with enhanced nodulation.These results indicate that MtROP8participates in root hair development and the establishmentof the symbiotic interaction by regulating ROS production and distribution.
