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Tomato Cells (tomato + cell)
Selected AbstractsPhosphatidic acid formation is required for extracellular ATP-mediated nitric oxide production in suspension-cultured tomato cellsNEW PHYTOLOGIST, Issue 4 2010Daniela J. Sueldo Summary ,In animals and plants, extracellular ATP exerts its effects by regulating the second messengers Ca2+, nitric oxide (NO) and reactive oxygen species (ROS). In animals, phospholipid-derived molecules, such as diacylglycerol, phosphatidic acid (PA) and inositol phosphates, have been associated with the extracellular ATP signaling pathway. The involvement of phospholipids in extracellular ATP signaling in plants, as it is established in animals, is unknown. ,In vivo phospholipid signaling upon extracellular ATP treatment was studied in 32Pi -labeled suspension-cultured tomato (Solanum lycopersicum) cells. ,Here, we report that, in suspension-cultured tomato cells, extracellular ATP induces the formation of the signaling lipid phosphatidic acid. Exogenous ATP at doses of 0.1 and 1 mm induce the formation of phosphatidic acid within minutes. Studies on the enzymatic sources of phosphatidic acid revealed the participation of both phospholipase D and C in concerted action with diacylglycerol kinase. ,Our results suggest that extracellular ATP-mediated nitric oxide production is downstream of phospholipase C/diacylglycerol kinase activation. [source] Ultrastructural aspects of tomato leaves infected by Tomato torrado virus (ToTV) and co-infected by other virusesPLANT PATHOLOGY, Issue 2 2010A. Alfaro-Fernández Optical and electron microscopy studies were carried out to investigate the cytopathology induced in tomato leaves infected by Tomato torrado virus (ToTV), a new picorna-like virus associated with the ,Torrado' disease. Infected leaves, showing typical Torrado disease symptoms were surveyed in commercial greenhouses in the main tomato production areas of Spain. The effect of the co-infection of ToTV with other viruses which commonly infect tomato crops was also studied. Ultra-thin sections of ToTV-infected tomato leaves did not show a strong cellular alteration. However, crystalline arrays of isometric virus-like particles (VLPs) of 20,30 nm in the inclusion bodies were observed in phloem parenchyma cells of the infected tissues. Tissues co-infected by ToTV and either Tomato chlorosis virus (ToCV) or Pepino mosaic virus (PepMV) presented more severe cellular alterations. The most deleterious consequences for tomato cells were found in triple infections of ToTV, PepMV and Tomato spotted wilt virus (TSWV), where characteristic cell wall overgrowth was distinguishable, together with a large amount of necrotic cells. [source] ABA activates ADPR cyclase and cADPR induces a subset of ABA-responsive genes in ArabidopsisTHE PLANT JOURNAL, Issue 3 2004Juan-Pablo Sánchez Summary Cyclic ADP-ribose (cADPR) was previously shown to activate transient expression of two abscisic acid (ABA)-responsive genes in tomato cells. Here, we show that the activity of the enzyme responsible for cADPR synthesis, ADP-ribosyl (ADPR) cyclase, is rapidly induced by ABA in both wild-type (WT) and abi1-1 mutant Arabidopsis plants in the absence of protein synthesis. Furthermore, in transgenic Arabidopsis plants, induced expression of the Aplysia ADPR cyclase gene resulted in an increase in ADPR cyclase activity and cADPR levels, as well as elevated expression of ABA-responsive genes KIN2, RD22, RD29a, and COR47 (although to a lesser extent than after ABA induction). Genome-wide profiling indicated that about 28% of all ABA-responsive genes in Arabidopsis are similarly up- and downregulated by cADPR and contributed to the identification of new ABA-responsive genes. Our results suggest that activation of ADPR cyclase is an early ABA-signaling event partially insensitive to the abi1-1 mutation and that an increase in cADPR plays an important role in downstream molecular and physiological ABA responses. [source] | ||||||||||