Cloning of taxadiene synthase gene into Arabidopsis thaliana (ecotype Columbia-0)

Paclitaxel (Taxol), a complex diterpenoid, produced by yew tree (Taxus sp.) is the most important chemotherapeutic agent that is widely used against a variety of malignancies such as ovarian and breast cancers. However, destructive methods for its production from natural resources together with currently used low-yielding industrial production systems via total synthesis or semi-synthesis have led researchers to invent a robust alternative biological production system using biotechnological approaches. The first committed step in taxol biosynthesis pathway is the  production of taxadiene from geranylgeranyl diphosphate (GGPP) catalyzed by the plastid-localized enzyme taxadiene synthase (TXS). In this research, an attempt was made to evaluate the effects of the first critical enzyme in thetaxol biosynthesis pathway on Arabidopsis plant through the expression of taxadiene synthase gene under the control of a dexamethasone-inducible promoter. To achieve this goal, Arabidopsis plants (ecotype Columbia-0) were transformed with the construct pTA-TXS-His via floral dip method using Agrobacterium tumefaciens AGL1. The transformed plants were confirmed using the PCR reaction amplifying an 800 bp fragment of the cloned gene. Upon these findings, a proposal was made that biotechnological strategies could be utilized for the production of taxol components

Fusarium oxysporum f.sp. radicis-lycopersici induces distinct transcriptome reprogramming in resistant and susceptible isogenic tomato lines

Background: Fusarium oxysporum f.sp. radicis-lycopersici (FORL) is one of the most destructive necrotrophic pathogens affecting tomato crops, causing considerable field and greenhouse yield losses. Despite such major economic impact, little is known about the molecular mechanisms regulating Fusarium oxysporum f.sp. radicis-lycopersici resistance in tomato. Results: A transcriptomic experiment was carried out in order to investigate the main mechanisms of FORL response in resistant and susceptible isogenic tomato lines. Microarray analysis at 15 DPI (days post inoculum) revealed a distinct gene expression pattern between the two genotypes in the inoculated vs non-inoculated conditions. A model of plant response both for compatible and incompatible reactions was proposed. In particular, in the incompatible interaction an activation of defense genes related to secondary metabolite production and tryptophan metabolism was observed. Moreover, maintenance of the cell osmotic potential after the FORL challenging was mediated by a dehydrationinduced protein. As for the compatible interaction, activation of an oxidative burst mediated by peroxidases and a cytochrome monooxygenase induced cell degeneration and necrosis. Conclusions: Our work allowed comprehensive understanding of the molecular basis of the tomato-FORL interaction. The result obtained emphasizes a different transcriptional reaction between the resistant and the susceptible genotype to the FORL challenge. Our findings could lead to the improvement in disease control strategies