RNA-seq analysis of lignocellulose-related genes in hybrid Eucalyptus with contrasting wood basic density.

Background: Wood basic density (WBD), the biomass of plant cell walls per unit volume, is an important trait for elite tree selection in kraft pulp production. Here, we investigated the correlation between WBD and wood volumes or wood properties using 98 open-pollinated, 2.4 to 2.

Transcriptional Profiles of Hybrid Eucalyptus Genotypes with Contrasting Lignin Content Reveal That Monolignol Biosynthesis-related Genes Regulate Wood Composition.

Eucalyptus species constitutes the most widely planted hardwood trees in temperate and subtropical regions. In this study, we compared the transcript levels of genes involved in lignocellulose formation such as cellulose, hemicellulose and lignin biosynthesis in two selected 3-year old hybrid Eucalyptus (Eucalyptus urophylla × Eucalyptus grandis) genotypes (AM063 and AM380) that have different lignin content. AM063 and AM380 had 20.

Enrichments of gene replacement events by -mediated recombinase-mediated cassette exchange.

We report recombinase-mediated cassette exchange (RMCE), which can permit integration of transgenes into pre-defined chromosomal loci with no co-expressed marker gene by using -mediated transformation. Transgenic tobacco plants which have a single copy of negative marker genes () at target loci in heterozygous and homozygous conditions were used for gene exchange by the RMCE method. By negative selection, we were able to obtain five heterozygous and four homozygous transgenic plants in which the genes were exchanged from 64 leaf segments of heterozygous and homozygous target plants, respectively.

A multi-year assessment of the environmental impact of transgenic Eucalyptus trees harboring a bacterial choline oxidase gene on biomass, precinct vegetation and the microbial community.

A 4-year field trial for the salt tolerant Eucalyptus globulus Labill. harboring the choline oxidase (codA) gene derived from the halobacterium Arthrobacter globiformis was conducted to assess the impact of transgenic versus non-transgenic trees on biomass production, the adjacent soil microbial communities and vegetation by monitoring growth parameters, seasonal changes in soil microbes and the allelopathic activity of leaves. Three independently-derived lines of transgenic E.

The choline oxidase gene codA confers salt tolerance to transgenic Eucalyptus globulus in a semi-confined condition.

The performance of tree species is influenced by environmental factors and growth stages. To evaluate the practical performance of transgenic tree species, it is insufficient to grow small, young trees under controlled conditions, such as in a growth chamber. Three transgenic Eucalyptus globulus lines, carrying the choline oxidase gene, were investigated for their salt tolerance and expression of the transgene at the young plantlet stage in a special netted-house.

Marker-free gene targeting by recombinase-mediated cassette exchange.

Repeated gene targeting by recombinase-mediated cassette exchange (RMCE) is an efficient tool for the study of gene function and regulation because of the high predictability and repeatability of gene expression. We have developed the site-directed integration (SDI) vector system for Agrobacterium-mediated transformation to precisely integrate a single copy of a desired gene into a predefined chromosomal locus in the absence of any coexpressed selection marker gene (Nanto et al. Plant Biotechnol J 3:203-214, 2005; Nanto and Ebinuma Transgenic Res 17:337-344, 2008; Nanto et al.

Agrobacterium-mediated transformation of Eucalyptus globulus using explants with shoot apex with introduction of bacterial choline oxidase gene to enhance salt tolerance.

Eucalyptus globulus is one of the most economically important plantation hardwoods for paper making. However, its low transformation frequency has prevented genetic engineering of this species with useful genes. We found the hypocotyl section with a shoot apex has the highest regeneration ability among another hypocotyl sections, and have developed an efficient Agrobacterium-mediated transformation method using these materials.

Monoterpene engineering in a woody plant Eucalyptus camaldulensis using a limonene synthase cDNA.

Metabolic engineering aimed at monoterpene production has become an intensive research topic in recent years, although most studies have been limited to herbal plants including model plants such as Arabidopsis. The genus Eucalyptus includes commercially important woody plants in terms of essential oil production and the pulp industry. This study attempted to modify the production of monoterpenes, which are major components of Eucalyptus essential oil, by introducing two expression constructs containing Perilla frutescens limonene synthase (PFLS) cDNA, whose gene products were designed to be localized in either the plastid or cytosol, into Eucalyptus camaldulensis.

Expression of a transgene exchanged by the recombinase-mediated cassette exchange (RMCE) method in plants.

We developed a site-directed integration (SDI) system for Agrobacterium-mediated transformation to precisely integrate a single copy of a desired gene into a predefined target locus by recombinase-mediated cassette exchange (RMCE). We produced site-specific transgenic tobacco plants from four target lines and examined expression of the transgene in T1 site-specific transgenic tobacco plants, which were obtained by backcrossing. We found that site-specific transgenic plants from the same target lines showed approximately the same level of expression of the transgene.

Marker-free site-specific integration plants.

Recently, site-specific recombination methods in plants have been developed to delete selection markers to produce marker-free transgenic plants or to integrate the transgene into a pre-determined genomic location to produce site-specific transgenic plants. However, these methods have been developed independently, and although the strategies of producing marker-free site-specific integration plants have been discussed, the concept has not been demonstrated. In the present study, we combined two approaches to site-specific recombination and demonstrated the concepts for removing the marker after site-specific integration for producing marker-free site-specific transgenic plants.

Agrobacterium-mediated RMCE approach for gene replacement.

We describe the site-directed integration (SDI) system for Agrobacterium-mediated transformation to precisely integrate a single copy of a desired gene into a predefined target locus by recombinase-mediated cassette exchange (RMCE). The system requires the selection of a transformed line with an integrated copy of a target cassette, and subsequent introduction of an exchange vector. The target cassette contains the npt and cod genes between oppositely orientated recognition sites (RS).