Integrated analysis of transcriptome and metabolome of Arabidopsis albino or pale green mutants with disrupted nuclear-encoded chloroplast proteins.

We used four mutants having albino or pale green phenotypes with disrupted nuclear-encoded chloroplast proteins to analyze the regulatory system of metabolites in chloroplast. We performed an integrated analyses of transcriptomes and metabolomes of the four mutants. Transcriptome analysis was carried out using the Agilent Arabidopsis 2 Oligo Microarray, and metabolome analysis with two mass spectrometers; a direct-infusion Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR/MS) and a gas chromatograph-time of flight mass spectrometer. Among approximately 200 known metabolites detected by the FT-ICR/MS, 71 metabolites showed significant changes in the mutants when compared with controls (Ds donor plants). Significant accumulation of several amino acids (glutamine, glutamate and asparagine) was observed in the albino and pale green mutants. Transcriptome analysis revealed altered expressions of genes in several metabolic pathways. For example, genes involved in the tricarboxylic acid cycle, the oxidative pentose phosphate pathway, and the de novo purine nucleotide biosynthetic pathway were up-regulated. These results suggest that nitrogen assimilation is constitutively promoted in the albino and pale green mutants. The accumulation of ammonium ions in the albino and pale green mutants was consistently higher than in Ds donor lines. Furthermore, genes related to pyridoxin accumulation and the de novo purine nucleotide biosynthetic pathway were up-regulated, which may have occurred as a result of the accumulation of glutamine in the albino and pale green mutants. The difference in metabolic profiles seems to be correlated with the disruption of chloroplast internal membrane structures in the mutants. In albino mutants, the alteration of metabolites accumulation and genes expression is stronger than pale green mutants.

Oxicam-type nonsteroidal anti-inflammatory drugs enhance Agrobacterium-mediated transient transformation in plants.

Agrobacterium-mediated transformation is a key innovation for plant breeding, and routinely used in basic researches and applied biology. However, the transformation efficiency is often the limiting factor of this technique. In this study, we discovered that oxicam-type nonsteroidal anti-inflammatory drugs, including tenoxicam (TNX), increase the efficiency of Agrobacterium-mediated transient transformation. TNX treatment increased the transformation efficiency of Agrobacterium-mediated transformation of Arabidopsis thaliana mature leaves by agroinfiltration. The increase of efficiency by TNX treatment was not observed in dde2/ein2/pad4/sid2 quadruple mutant, indicating that TNX inhibits the immune system mediated by jasmonic acid, ethylene, and salicylic acid against to Agrobacterium. We also found that TNX-treatment is applicable for the transient expression and subcellular localization analysis of fluorescent-tagged proteins in Arabidopsis leaf cells. In addition, we found that TNX increases the efficiency of Agrobacterium-mediated transient transformation of Jatropha. Given that treatment with oxicam compounds is a simple and cost effective method, our findings will provide a new option to overcome limitations associated with Agrobacterium-mediated transformation of various plant species.

Transformation of Jatropha curcas L. for production of larger seeds and increased amount of biodiesel.

The development of green energy is important to mitigate global warming. Jatropha (Jatropha curcas L.) is a promising candidate for the production of alternative biofuel, which could reduce the burden on the Earth's resources. Jatropha seeds contain a large quantity of lipids that can be used to produce biofuel, and the rest of the plant has many other uses. Currently, techniques for plant genetic transformation are extensively employed to study, create, and improve the specific characteristics of the target plant. Successful transformation involves the alteration of plants and their genetic materials. The aim of this study was to generate Jatropha plants that can support biofuel production by increasing their seed size using genes found via the rice FOX-hunting system. The present study improved previous protocols, enabling the production of transgenic Jatropha in two steps: the first step involved using auxins and dark incubation to promote root formation in excised shoots and the second step involved delaying the timing of antibiotic selection in the cultivation medium. Transgenic plants were subjected to PCR analysis; the transferred gene expression was confirmed via RT-PCR and the ploidy level was investigated. The results suggest that the genes associated with larger seed size in Arabidopsis thaliana, which were found using the rice FOX-hunting system, produce larger seeds in Jatropha.