Plant Transformation: Advances and Perspectives

Abstract

Genetic transformation is a powerful tool for plant breeding and genetical, physiological or biochemical research, consequently it is an extremely dynamic field. Transgenic plants are commonly used to complete or substitute mutants in basic research, helping the studies of complex biological situations such as pathogenesis process, genome organization, light reception and signal transduction. In this review, recent approaches for foreign gene introduction (e.g. Agrobiolistics, whole tissue electroporation, in planta Agrobacterium transformation), screening (reporter gene possibilities and performance) and transformant selection (ipt selective marker) are discussed. Transgene expression and mechanisms underlying (trans)gene inactivation are presented. Practical applications of genetically modified plants, field tests and commercial transgenic crops worldwide and in Brazil are listed, as well as the main traits and species modified. Potential uses of transgenic plants for animal compound production, biological remediation and synthetic polymer assembly are also shown.

Technique of Overlap Extension by Polymerase Chain Reaction for Splicing Cauliflower Mosaic Virus (CaMV) 35S Promoter and DhPEX11-Like

“…Cauliflower Mosaic Virus (CaMV) and the closely related Figwort Mosaic Virus are circular duplex DNA viruses which replicate via transcription of a fulllength (35S) genomic RNA intermediate [12]. The cauliflower mosaic virus (CaMV) 35S promoter is a strong and constitutive promoter that widely used for production purposes [13,14].…”

Factors affecting somatic embryogenesis and transformation in modern plant breeding

“…With the advent of chemotatic chemicals such as acetosyringone, Agrobacterium transformation of monocots such as rice, wheat and banana has materialized. Regardless of the method employed, every stable transformation process demands the simultaneous occurrence of two independent biological events: the stable insertion of the transgene into the plant genome and regeneration from those cells in which this has occurred, producing a non-chimeric transgenic plant (Alves et al, 1999).…”

“…Transformation is the introduction of exogenous DNA into plant cells, tissues or organs employing direct or indirect means (Alves et al, 1999). Indirect gene transfer involves the introduction of exogenous DNA by a biological vector such as Agrobacterium, whereas direct gene transfer involves introduction of exogenous DNA by physical or chemical processes such as electroporation, polyethylene glycol mediated DNA uptake, microinjection, silicon carbide fibres and microprojectile bombardment (Taylor and Fauquet, 2002).…”

“…One of the major objectives of plant transformation has been to solve agricultural problems without environmental damage (Alves et al, 1999). Following the advent of pioneer transgenic plants containing marker genes, todays transgenic crops are incorporated with commercial value genes and the most commonly used traits are herbicide tolerance (35 %), product quality (20 %), insect resistance (18 %), virus resistance (11 %), fungal resistance (3 %), nematode and bacterial resistance and marker or reporter genes (13 %) (Alves et al, 1999;Vines, 2001;Koichi et al, 2002). Other valuable genes are used to generate nutritionally enhanced crops with altered carbohydrate, starch, protein or lipid characteristics, higher vitamin or anti-oxidants content, improved taste, increased shelf-life and better ripening characteristics.…”

“…Constitutive promoters cause gene expression throughout the life of the plant in most tissues. The most widely used constitutive promoter is CaMV 35S derived from cauliflower mosaic virus (Alves et al, 1999). Häggman and Aronen (1998) reported very high transient GUS expression in Scots pine embryogenic cultures using the constitutive CaMV 35S promoter.…”