Exogenous abscisic acid(ABA)can inhibit root growth and promote formation of more root hairs in the root tip of Arabidopsis.However,the molecular mechanisms that underlie root ABA signaling are largely unknown.We repo...Exogenous abscisic acid(ABA)can inhibit root growth and promote formation of more root hairs in the root tip of Arabidopsis.However,the molecular mechanisms that underlie root ABA signaling are largely unknown.We report here that hydrogen peroxide(H2O2)reduces the root growth of wild type, and the phenotype of H2O2 on the root growth is similar to ABA response.Meanwhile ABA-induced changes in the morphology of root system can be partly reversed by ascorbic acid in wild type and abolished in NADPH oxidase defective mutant atrbohF and atrbohC.Further,ABA can induce H2O2 accumulation in the root cells and enhance transcription level of OXI1,which is necessary for many more AOS-dependent processes such as root hair growth in Arabidopsis.Our results suggest that H2O2 as an important signal molecule is required for the ABA-regulated root growth and development in Arabidopsis.展开更多
The phytohormone abscisic acid(ABA)plays an important role in plant growth and development,for example in seed dormancy and germination,as well as in plant responses to environmental stresses,such as drought and high ...The phytohormone abscisic acid(ABA)plays an important role in plant growth and development,for example in seed dormancy and germination,as well as in plant responses to environmental stresses,such as drought and high salinity.Previous studies have shown that ABA regulates the expression of genes with an ABA-responsive element(ABRE)and their corresponding physiological responses.Bioinformatics analysis identified a GRAM domain-containing gene family that has a multiple ABRE cis-element,which was termed the ABA-responsive protein(ABR)family.To analyze the function of the ABR family,we identified homozygous T-DNA insertion mutants and constructed abr1,2,3 double mutants and triple mutant.The abr1,abr2 and abr3single mutants showed a normal phenotype;however,the germination of seeds of the double mutants and triple mutant were insensitive to ABA,NaCl,mannitol and glucose.ABR1-GFP was distributed as a punctate structure in the cytosol and may be localized in the endomembrane system.The ABR2-GFP and ABR3-GFP proteins localized in the cytoplasm.In addition,ABR1,ABR2 and ABR3 were expressed in various tissues,and could be induced by several abiotic stresses,especially by ABA.The expressions of these genes were significantly suppressed in aba2,abi1 and abi2 null mutants.These results suggested that the ABR family may act downstream of ABI1 and ABI2 in the ABA signal transduction process in plants.展开更多
Gene expression of glutathione peroxidase 3 (ATGPX3) in response to osmotic stress was analyzed in Arabidopsis using ATGPX3 promoter-glucuronidase (GUS) transgenic plants. High levels of GUS ex- pression were detected...Gene expression of glutathione peroxidase 3 (ATGPX3) in response to osmotic stress was analyzed in Arabidopsis using ATGPX3 promoter-glucuronidase (GUS) transgenic plants. High levels of GUS ex- pression were detected under osmotic stress in ATGPX3 promoter-GUS transgenic plants. Compared with the wild type, the growth and development of ATGPX3 mutants (atgpx3-1) were more sensitive to mannitol. In addition, the expression of RD29A, ABI1, ABI2 and RbohD in atgpx3-1 was induced by ABA stress. These results suggest that ATGPX3 might be involved in the signal transduction of osmotic stress.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.30370765,30530430 and 30625005)
文摘Exogenous abscisic acid(ABA)can inhibit root growth and promote formation of more root hairs in the root tip of Arabidopsis.However,the molecular mechanisms that underlie root ABA signaling are largely unknown.We report here that hydrogen peroxide(H2O2)reduces the root growth of wild type, and the phenotype of H2O2 on the root growth is similar to ABA response.Meanwhile ABA-induced changes in the morphology of root system can be partly reversed by ascorbic acid in wild type and abolished in NADPH oxidase defective mutant atrbohF and atrbohC.Further,ABA can induce H2O2 accumulation in the root cells and enhance transcription level of OXI1,which is necessary for many more AOS-dependent processes such as root hair growth in Arabidopsis.Our results suggest that H2O2 as an important signal molecule is required for the ABA-regulated root growth and development in Arabidopsis.
基金supported by the National Natural Science Foundation of China(91117002)
文摘The phytohormone abscisic acid(ABA)plays an important role in plant growth and development,for example in seed dormancy and germination,as well as in plant responses to environmental stresses,such as drought and high salinity.Previous studies have shown that ABA regulates the expression of genes with an ABA-responsive element(ABRE)and their corresponding physiological responses.Bioinformatics analysis identified a GRAM domain-containing gene family that has a multiple ABRE cis-element,which was termed the ABA-responsive protein(ABR)family.To analyze the function of the ABR family,we identified homozygous T-DNA insertion mutants and constructed abr1,2,3 double mutants and triple mutant.The abr1,abr2 and abr3single mutants showed a normal phenotype;however,the germination of seeds of the double mutants and triple mutant were insensitive to ABA,NaCl,mannitol and glucose.ABR1-GFP was distributed as a punctate structure in the cytosol and may be localized in the endomembrane system.The ABR2-GFP and ABR3-GFP proteins localized in the cytoplasm.In addition,ABR1,ABR2 and ABR3 were expressed in various tissues,and could be induced by several abiotic stresses,especially by ABA.The expressions of these genes were significantly suppressed in aba2,abi1 and abi2 null mutants.These results suggested that the ABR family may act downstream of ABI1 and ABI2 in the ABA signal transduction process in plants.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 30370765 & 30530430)the National Key Basic Special Founds (Grant No. 2003CB114305)the Natural Science Foundation of Henan Province (Grant No. 0411031400)
文摘Gene expression of glutathione peroxidase 3 (ATGPX3) in response to osmotic stress was analyzed in Arabidopsis using ATGPX3 promoter-glucuronidase (GUS) transgenic plants. High levels of GUS ex- pression were detected under osmotic stress in ATGPX3 promoter-GUS transgenic plants. Compared with the wild type, the growth and development of ATGPX3 mutants (atgpx3-1) were more sensitive to mannitol. In addition, the expression of RD29A, ABI1, ABI2 and RbohD in atgpx3-1 was induced by ABA stress. These results suggest that ATGPX3 might be involved in the signal transduction of osmotic stress.
