Protein kinases play crucial roles in response to external environment stress signals. A putative protein kinase, W55a, belonging to SNFl-related protein kinase 2 （SnRK2） subfamily, was isolated from a cDNA library ...Protein kinases play crucial roles in response to external environment stress signals. A putative protein kinase, W55a, belonging to SNFl-related protein kinase 2 （SnRK2） subfamily, was isolated from a cDNA library of drought-treated wheat seedlings. The entire length of W55a was obtained using rapid amplification of 5＇ cDNA ends （5＇-RACE） and reverse transcription-polymerase chain reaction（RT-PCR）. It contains a 1 029-bp open reading frame （ORF） encoding 342 amino acids. The deduced amino acid sequence of W55a had eleven conserved catalytic subdomains and one Ser/Thr protein kinase active-site that characterize Ser/Thr protein kinases. Phylogenetic analysis showed that W55a was 90.38% homologous with rice SAPK1, a member of the SnRK2 family. Using nullisomic-tetrasomic and ditelocentric lines of Chinese Spring, W55a was located on chromosome 2BS. Expression pattern analysis revealed that W55a was upregulated by drought and salt, exogenous abscisic acid, salicylic acid, ethylene and methyl jasmonate, but was not responsive to cold stress. In addition, W55a transcripts were abundant in leaves, but not in roots or stems, under environmental stresses. Transgenic Arabidopsis plants overexpressing W55a exhibited higher tolerance to drought. Based on these findings, W55a encodes a novel dehydration-responsive protein kinase that is involved in multiple stress signal transductions.展开更多
Regulation of iron uptake and use is critical for plant survival and growth. We isolated an MYB gene from Malus xiaojinensis named MxMYB1, which is induced under Fe-deficient conditions. Expression of MxMYB1 was upreg...Regulation of iron uptake and use is critical for plant survival and growth. We isolated an MYB gene from Malus xiaojinensis named MxMYB1, which is induced under Fe-deficient conditions. Expression of MxMYB1 was upregulated by Fe starvation in the roots but not in leaves, suggesting that MxMYB1 might play a role in iron nutrition in roots. Transgenic Arabidopsis plants expressing MxMYB1 exhibited lower iron content as compared with wild type plants under both Fe-normal （40 μM） and Fe-deficient conditions （Fe omitted and Ferrozine 300 μM）. However, the contents of Cu, Zn and Mn were not changed in these transgenic plants. Gene chip and real-time polymerase chain reaction analyses indicated that the expression of two Fe-related genes encoding an iron transporter AtlRT1 and an iron storage protein ferritin AtFER1 might be negatively regulated by MxMYB1 as the expression levels of these genes were lower in MxMYB1 expressing transgenic Arabidopsis plants as compared with wild type plants under both Fe-normal and Fe-deficient conditions. These results suggest that MxMYB1 may function as a negative regulator of iron uptake and storage in plants.展开更多
本文克隆了RIN4(RPM1-interacting protein 4)在胡杨中的同源基因PeRIN4,并在拟南芥中进行过表达,通过研究转基因株系的耐盐表型、质膜H^+-ATPsae活性及H^+、Na^+、K^+等的动态离子流,揭示了PeRIN4基因在植物响应和适应盐胁迫环境中的...本文克隆了RIN4(RPM1-interacting protein 4)在胡杨中的同源基因PeRIN4,并在拟南芥中进行过表达,通过研究转基因株系的耐盐表型、质膜H^+-ATPsae活性及H^+、Na^+、K^+等的动态离子流,揭示了PeRIN4基因在植物响应和适应盐胁迫环境中的作用。利用定位载体p Green0029-PeRIN4-GFP瞬时转化拟南芥叶肉细胞原生质体的方法,对胡杨PeRIN4蛋白进行亚细胞定位,发现该蛋白定位在细胞的胞质中。耐盐表型实验结果显示,在100 mmol/L NaCl处理下,拟南芥PeRIN4过表达株系(OE1和OE8)的生存率和根长均明显高于野生型(WT)和转空载体拟南芥(VC),说明PeRIN4基因能够提高拟南芥的耐盐性。与WT和VC相比,拟南芥PeRIN4过表达株系质膜H^+-ATPsae的活性较高。动态离子流数据显示,在盐胁迫下,PeRIN4过表达株系外排H^+和Na^+离子的能力强于野生型和转空载体拟南芥,然而K+的外流却弱于WT和VC。因此,PeRIN4蛋白具有调节质膜H^+-ATPsae活性的功能。拟南芥质膜H^+-ATPsae活性的提高主要有两方面的作用:一是可以增强H+泵的质子动力势,驱动Na^+/H^+逆向转运蛋白,提高Na^+外排的能力;二是抑制质膜的去极化,减少K+离子通过去极化激活的外向型K^+通道(DA-KORCs)和非选择性阳离子通道(DA-NSCCs)外流,维持了K^+/Na^+平衡,从而提高PeRIN4转基因拟南芥的耐盐性。展开更多
基金Supported by the Hi-Tech Research and Development Program (863) of China (2007AA10Z130)the National Natural Science Foundation ofChina (30700504).
文摘Protein kinases play crucial roles in response to external environment stress signals. A putative protein kinase, W55a, belonging to SNFl-related protein kinase 2 （SnRK2） subfamily, was isolated from a cDNA library of drought-treated wheat seedlings. The entire length of W55a was obtained using rapid amplification of 5＇ cDNA ends （5＇-RACE） and reverse transcription-polymerase chain reaction（RT-PCR）. It contains a 1 029-bp open reading frame （ORF） encoding 342 amino acids. The deduced amino acid sequence of W55a had eleven conserved catalytic subdomains and one Ser/Thr protein kinase active-site that characterize Ser/Thr protein kinases. Phylogenetic analysis showed that W55a was 90.38% homologous with rice SAPK1, a member of the SnRK2 family. Using nullisomic-tetrasomic and ditelocentric lines of Chinese Spring, W55a was located on chromosome 2BS. Expression pattern analysis revealed that W55a was upregulated by drought and salt, exogenous abscisic acid, salicylic acid, ethylene and methyl jasmonate, but was not responsive to cold stress. In addition, W55a transcripts were abundant in leaves, but not in roots or stems, under environmental stresses. Transgenic Arabidopsis plants overexpressing W55a exhibited higher tolerance to drought. Based on these findings, W55a encodes a novel dehydration-responsive protein kinase that is involved in multiple stress signal transductions.
基金Partially supported by the National Natural Science Foundation of China(30671441)the Hi-Tech Research and Development (863) Program ofChina (2006AA10Z1B6)the key laboratory of Beijing Municipality(JD100190532).
文摘Regulation of iron uptake and use is critical for plant survival and growth. We isolated an MYB gene from Malus xiaojinensis named MxMYB1, which is induced under Fe-deficient conditions. Expression of MxMYB1 was upregulated by Fe starvation in the roots but not in leaves, suggesting that MxMYB1 might play a role in iron nutrition in roots. Transgenic Arabidopsis plants expressing MxMYB1 exhibited lower iron content as compared with wild type plants under both Fe-normal （40 μM） and Fe-deficient conditions （Fe omitted and Ferrozine 300 μM）. However, the contents of Cu, Zn and Mn were not changed in these transgenic plants. Gene chip and real-time polymerase chain reaction analyses indicated that the expression of two Fe-related genes encoding an iron transporter AtlRT1 and an iron storage protein ferritin AtFER1 might be negatively regulated by MxMYB1 as the expression levels of these genes were lower in MxMYB1 expressing transgenic Arabidopsis plants as compared with wild type plants under both Fe-normal and Fe-deficient conditions. These results suggest that MxMYB1 may function as a negative regulator of iron uptake and storage in plants.
