RESUMO
Bioactive gibberellins (GAs) are a type of important plant growth regulators, which play the key roles in multiple processes, such as seed germination, leaf expansion, flowering, fruit bearing, and stem development. Its biosynthesis is regulated by a variety of enzymes including gibberellin 3-oxidase that is a key rate-limiting enzyme. In Arabidopsis, gibberellin 3-oxidase consists of four members, of which AtGA3OX1 and AtGA3OX2 are highly expressed in stems, suggesting the potential roles in the stem development played by the two genes. To date, there are few studies on AtGA3OX1 and AtGA3OX2 regulating secondary wall thickening in stems. In this study, we used the atga3ox1atga3ox2 double mutant as the materials to study the effects of AtGA3OX1 and AtGA3OX2 genes on secondary wall thickening in stems. The results indicated that simulations repression of AtGA3OX1 and AtGA3OX2 genes resulted in significantly reduction of secondary wall thickening of fiber cells, but not that of vessel cells. Three main components (cellulose, hemicelluloses, and lignin) were also dramatically suppressed in the double mutants. qRT-PCR analysis demonstrated that the expressions of secondary wall biosynthetic genes and the associated transcription factors were obviously affected in AtGA3OX1 and AtGA3OX2 double mutant. Therefore, we presume that Arabidopsis AtGA3OX1 and AtGA3OX2 genes might activate the expression of these transcription factors, thus regulate secondary wall thickening in stems. Together, our results provide a theoretical basis for enhancing the lodging resistance of food crops and improving the biomass of energy plants by genetically engineering Arabidopsis AtGA3OX homologs.
Assuntos
Arabidopsis/enzimologia , Parede Celular/metabolismo , Oxigenases de Função Mista/metabolismo , Caules de Planta/metabolismo , Arabidopsis/química , Arabidopsis/genética , Arabidopsis/metabolismo , Parede Celular/genética , Celulose/metabolismo , Regulação da Expressão Gênica de Plantas , Oxigenases de Função Mista/química , Oxigenases de Função Mista/genética , Dados de Sequência Molecular , Filogenia , Caules de Planta/genética , Plantas/classificação , Plantas/enzimologia , Homologia de Sequência de AminoácidosRESUMO
A rice (Oryza sativa L.) mutant with a high-tillering capacity, designated as ht1, was found from a japonica rice variety Xindao18. This high-tillering mutant phenotype was stably expressed through successive five self-crossed generations, and the number of tillers in mutants was three times more than that in wild-type rice. Genetic analysis showed that the phenotype of ht1was controlled by a single dominant nuclear gene, temporarily designated as HT1. By means of molecular marker technique, the HT1 gene was mapped to an interval between two SSR markers RM25435 and RM25552 on chro-mosome 10. Through high-resolution linkage analysis, the HT1 gene was further restricted to a 0.1 cM region flanked by two SSR markers RM25523 and RM25532. The physical distance between these two markers is about 130kb.
Assuntos
Mapeamento Cromossômico , Mutação , Oryza/genética , Locos de Características QuantitativasRESUMO
CMS in rapeseed is of tremendous importance in its commercial application in hybrid seed production. This review focuses on the progresses of study on CMS in rapeseed from four aspects: (1) the mitochondrial DNA locus found to be associated with CMS, (2) the effects of restorer gene for fertility on the expression of the locus associated with CMS, (3) the mapping with molecular marker and (4) cloning of restorer genes of fertility of the CMS in rapeseed. The prospects of further studies on this subject are discussed.
Assuntos
Brassica rapa/genética , DNA de Plantas/genética , Genes de Plantas/genética , Infertilidade das Plantas/genética , DNA Mitocondrial/genética , Fertilidade/genéticaRESUMO
Transgenic plants can transfer foreign genes through pollen or seed to related plant species. This may cause potential harm to ecological environment. How to decrease the gene flow is drawing a growing public attention. The approaches for decreasing the gene flow include chloroplast transformation, pollen sterility, seed sterility, cleistogamy, apomixis, temporal control, and transgenic mitigation. The theoretical basis, advantages and disadvantages, and usage status of these approaches are presented in this review.
Assuntos
Ecossistema , Poluição Ambiental/prevenção & controle , Fluxo Gênico , Genes de Plantas , Plantas Geneticamente Modificadas/genética , Cloroplastos/genética , Plantas Geneticamente Modificadas/efeitos adversos , Pólen/genética , Sementes/genéticaRESUMO
The chloroplast genome transformation of higher plant has become the research hotspot of plant genetic engineering with several advantages over nuclear genetic engineering, and it has become into a powerful approach for both basic and applied research. This paper presents a brief summary for the principle and methods of chloroplast genome transformation in higher plant. The particular emphasis was placed on its application in the basic and applied research. These applications include the studies of rearrangement of Rubisco and the structure, transcription, translation and RNA editing of genes in chloroplast; the producing of antibodies, vaccines, poly-beta-hydroxybutyrate and bio-elastic protein using chloroplast as bioreactor; the generating of transgenic plants with resistance to insect, disease, herbicide and drought; and the decreasing the gene flow of transgenic plants.
Assuntos
Genoma de Cloroplastos/genética , Plantas Geneticamente Modificadas/genética , Plantas/genética , Transformação Genética , Cloroplastos/genética , Imunidade Inata/genética , Doenças das Plantas/genéticaRESUMO
Apomixis allows the establishment of genetically stable seed propagating clones of crops, which can perpetuate themselves across countless sporophytic generations. This asexual mode of reproduction, which naturally occurs in some angiosperms,may prove to be an unrivalled tool to improve crop yields. The current state of knowledge on the molecular and genetic basis of apomixis is reviewed.
