Overexpressing the HD-Zip class II transcription factor EcHB1 from Eucalyptus camaldulensis increased the leaf photosynthesis and drought tolerance of Eucalyptus.

Alteration in the leaf mesophyll anatomy by genetic modification is potentially a promising tool for improving the physiological functions of trees by improving leaf photosynthesis. Homeodomain leucine zipper (HD-Zip) transcription factors are candidates for anatomical alterations of leaves through modification of cell multiplication, differentiation, and expansion. Full-length cDNA encoding a Eucalyptus camaldulensis HD-Zip class II transcription factor (EcHB1) was over-expressed in vivo in the hybrid Eucalyptus GUT5 generated from Eucalyptus grandis and Eucalyptus urophylla.

Identification of a STOP1-like protein in Eucalyptus that regulates transcription of Al tolerance genes.

Tolerance to soil acidity is an important trait for eucalyptus clones that are introduced to commercial forestry plantations in pacific Asian countries, where acidic soil is dominant in many locations. A conserved transcription factor regulating aluminum (Al) and proton (H⁺) tolerance in land-plant species, STOP1 (SENSITIVE TOPROTON RHIZOTOXICITY 1)-like protein, was isolated by polymerase chain reaction-based cloning, and then suppressed by RNA interference in hairy roots produced by Agrobacterium rhizogenes-mediated transformation. Eucalyptus STOP1-like protein complemented proton tolerance in an Arabidopsis thaliana stop1-mutant, and localized to the nucleus in a transient assay of a green fluorescent protein fusion protein expressed in tobacco leaves by Agrobacterium tumefaciens-mediated transformation.

Development of the gateway recycling cloning system for multiple linking of expression cassettes in a defined order, and direction on gateway compatible binary vectors.

We developed the Gateway recycling cloning system, which allows multiple linking of expression cassettes by multiple rounds of the Gateway LR reaction. Employing this system, the recycling donor vector pRED419 was subjected to the first LR reaction with an attR1-attR2 type destination vector. Then conversion vector pCON was subjected to an LR reaction to restore the attR1-attR2 site on the destination vector for the next cloning cycle.

Characterization of Al-responsive citrate excretion and citrate-transporting MATEs in Eucalyptus camaldulensis.

Many plant species excrete organic acids into the rhizosphere in response to aluminum stress to protect sensitive cells from aluminum rhizotoxicity. When the roots of Eucalyptus camaldulensis, a major source of pulp production, were incubated in aluminum-toxic medium, citrate released into the solution increased as a function of time. Citrate excretion was inducible by aluminum, but not by copper or sodium chloride stresses.

Stable production of thermotolerant xylanase B of Clostridium stercorarium in transgenic tobacco and rice.

The xylanase B gene encoding a thermostable family 10 xylanase of Clostridium stercorarium was expressed in plants under the control of a constitutive promoter. Two forms of the xylanase B gene, the xynB gene encoding the full length of the xylanase B gene including the bacterial signal sequence and the xynBM gene without the signal sequence region, were introduced into tobacco BY-2 cells and tobacco plants respectively under the control of the cauliflower mosaic virus 35S promoter. Transgenic BY-2 cells and tobacco plants showed xylanase activity and normal growth.

Differences in Rubisco content and its synthesis in leaves at different positions in Eucalyptus globulus seedlings.

The dynamics of ribulose 1.5-bisphosphate carboxylase/oxygenase (Rubisco) content and turnover during leaf development are not well understood in woody plants. Rubisco synthesis, N influx and the mRNA levels of Rubisco-encoding genes were determined as a function of leaf position in 4.

Effect of overexpression of radish plasma membrane aquaporins on water-use efficiency, photosynthesis and growth of Eucalyptus trees.

Eucalyptus is a diverse genus of flowering trees with more than 700 genotypic species which are mostly native to Australia. We selected 19 wild provenances of Eucalyptus camaldulensis grown in Australia, compared their growth rate and drought tolerance and determined the protein levels of plasma membrane aquaporins (PIPs). There was a positive relationship between the drought tolerance and PIP content.

Simple identification of transgenic Arabidopsis plants carrying a single copy of the integrated gene.

Transgenic Arabidopsis thaliana plants carrying a single copy of integrated DNA can be identified by single-step genomic polymerase chain reaction. The reaction employs two sets of primer pairs with the same melting temperature that amplify the amplicons derived from the integrated T-DNA together with those from an endogenous single-copy gene as a reference. When the band intensity ratio is one, this means that the transgenic plants are carrying a single copy of the integrated gene per haploid.

An Analysis of the Mechanism of the Low-wave Phenomenon of Chlorophyll Fluorescence.

The low-wave phenomenon, i.e., the transient drop of yield of modulated chlorophyll fluorescence shortly after application of a pulse of saturating light, was investigated in intact leaves of tobacco and Camellia by measuring fluorescence, CO(2) assimilation and absorption at 830 nm simultaneously.

Promoter of Arabidopsis thaliana phosphate transporter gene drives root-specific expression of transgene in rice.

The PHT1 promoter::GUS fusion gene was constructed and introduced into Arabidopsis and rice by Agrobacterium-mediated transformation. Strong beta-glucuronidase (GUS) activity was detected in roots and showed phosphate starvation induction both in Arabidopsis and rice. In contrast, GUS activity in aerial tissues such as those of the leaf and stem was low.