RESUMO
Cation transport is thought to be an important process for ion homeostasis in plant cells. Here, we report that a soybean putative cation/proton antiporter GmCAX1 may be a mediator of this process. GmCAX1 is expressed in all tissues of the soybean plants but at a lower level in roots. Its expression was induced by PEG, ABA, Ca(2+), Na(+) and Li(+) treatments. The GmCAX1-GFP fusion protein was mainly localized in plasma membrane of the transgenic Arabidopsis plant cells and onion epidermal cells. Transgenic Arabidopsis plants overexpressing GmCAX1 accumulated less Na(+), K(+), and Li(+), and were more tolerant to elevated Li(+) and Na(+) levels during germination when compared with the controls. These results suggest that GmCAX1 may function as an antiporter for Na(+), K(+) and Li(+). Modulation of this antiporter may be beneficial for regulation of ion homeostasis and thus plant salt tolerance.
Assuntos
Antiporters/genética , Antiporters/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Membrana Celular/metabolismo , Glycine max/genética , Lítio/farmacologia , Cloreto de Sódio/farmacologia , Sequência de Aminoácidos , Antiporters/química , Arabidopsis/citologia , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Ligação ao Cálcio/química , Proteínas de Transporte de Cátions/química , Regulação da Expressão Gênica de Plantas , Lítio/metabolismo , Dados de Sequência Molecular , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Cloreto de Sódio/metabolismoRESUMO
Three DREB homologue genes, GmDREBa, GmDREBb, and GmDREBc, were isolated from soybean, Glycine max (L.) Merr. Each of the deduced proteins contains an AP2 domain of 64 amino acids. Yeast one-hybrid assay revealed that all of the three dehydration-responsive, element-binding proteins specifically bound to the dehydration-responsive element. Analysis of transcriptional activation abilities of these proteins in yeast indicated that GmDREBa and GmDREBb could activate the expression of a reporter gene, whereas GmDREBc could not. The transcriptions of GmDREBa and GmDREBb were induced by salt, drought, and cold stresses in leaves of soybean seedlings. The expression of GmDREBc was not significantly affected in leaves but apparently induced in roots by salt, drought, and abscisic acid treatments. These results suggest that these three genes function specifically in response to abiotic stresses in soybean.
Assuntos
Desidratação/metabolismo , Regulação da Expressão Gênica de Plantas , Glycine max/genética , Folhas de Planta/metabolismo , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Clonagem Molecular , Análise por Conglomerados , Primers do DNA , Desidratação/genética , Dados de Sequência Molecular , Filogenia , Ligação Proteica , Estrutura Terciária de Proteína , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência , Fatores de Transcrição/genética , Técnicas do Sistema de Duplo-Híbrido , LevedurasRESUMO
By using cDNA-AFLP, we analyzed a recombinant inbred line population of soybean that was derived from a soybean mosaic virus (SMV) resistant cultivar Kefeng No.1 and a susceptible cultivar Nannong 1138-2. One hundred and eight fragments showing polymorphism between SMV resistant and susceptible pools were identified. One fragment w27 was 96 bp in length and showed homology to homeobox ggth with a coding region of 738 bp, encoding a protein of 245 amino acids. The genomic sequence analysis defined an intron of 521 bp in the coding region. GmHZ1 was characterized by the presence of a homeodomain (HD) with a closely linked leucine zipper motif (Zip). Southern blot analysis indicated that there was a single copy of GmHZ1 in the soybean genome. When inoculated with SMV strain N3, resistant and susceptible varieties showed reduced and increased expression of the GmHZ1, respectively. The fusion protein of GmHZ1 with GFP was targeted only in nucleus. Yeast two hybrid studies revealed that the GmHZ1 had transcriptional activation activity and can form homodimer. GmHZ1 can bind two 9-bp pseudopalindromic elements (CAAT(A/T)ATTG and CAAT(C/G)ATTG) with different affinity. Using GUS as a reporter gene, GmHZ1 was proved to be a transcriptional activator and enhanced GUS expression by binding with the two elements in plant cells. These results indicate that the GmHZ1 may have a transcriptional activator function in plant response to SMV infection.
Assuntos
Glycine max/genética , Proteínas de Homeodomínio/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Genes de Plantas/fisiologia , Proteínas de Homeodomínio/química , Proteínas de Homeodomínio/metabolismo , Zíper de Leucina , Dados de Sequência Molecular , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Glycine max/metabolismo , Transcrição Gênica , Ativação TranscricionalRESUMO
Cell division is a fundamental biological process sharing conserved features and controls in all eukaryotes. The cell cycle is usually divided into four phases: G1, S, G2, and M. Regulated gene expression is an important mechanism for controlling cell cycle progression and genes involved in cell division-related processes often show transcriptional regulation dependent on cell cycle position. In the present report, a novel cell cycle-related gene (AtCPR) from Arabidopsis thaliana was isolated and characterized. Sequence analysis revealed that the deduced amino acid sequence of AtCPR showed 53.2% identity with p38-2G4, a mouse G1-to-S cell cycle specifically modulated and proliferation-associated nuclear protein. Assay of expression of AtCPR in partially synchronized cells suggested that AtCPR mRNA was expressed in the G1-to-S phase. In the AtCPR transgenic plants, no apparent phenotypic change was observed. By fusing a GFP tag to the AtCPR protein, it was found that AtCPR was mainly located in the nucleus. However, AtCPR does not have any transcriptional activation ability. cDNA microarray analysis showed that a total of 17 and 30 genes were identified as up-regulated and down-regulated, respectively.
Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Proteínas Nucleares/genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Arabidopsis/citologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/biossíntese , Proteínas de Arabidopsis/química , Ciclo Celular/genética , Regulação para Baixo , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Dados de Sequência Molecular , Proteínas Nucleares/biossíntese , Proteínas Nucleares/química , Análise de Sequência com Séries de Oligonucleotídeos , Plantas Geneticamente Modificadas , Homologia de Sequência de Aminoácidos , Regulação para Cima/fisiologiaRESUMO
A full-length gene GmPti1 was identified from soybean in an EST sequencing project by its homology to tomato Pti1. It encoded a protein of 366 amino acids. RT-PCR analysis showed that the GmPti1 expression was induced by salicylic acid and wounding. The deduced amino acid sequence had a Ser/Thr/Tyr kinase domain. GmPti1 protein was expressed in E. coli as an MBP fusion, purified by amylose resin and examined for its autophosphorylation ability. The phosphorylation assay in vitro showed that GmPti1 had kinase activity in the presence of Mn2+. These results demonstrated that GmPti1 represented a new Pti1-like gene, unlike the two published genes sPti1a and sPti1b, which encoding proteins had no autophosphorylation ability.
