Possible Role of Peroxynitrite in the Responses Induced by Fusicoccin in Plant Cultured Cells.

Fusicoccin (FC) is a well-known phytotoxin able to induce in L. (sycamore) cultured cells, a set of responses similar to those induced by stress conditions. In this work, the possible involvement of peroxynitrite (ONOO) in FC-induced stress responses was studied measuring both in the presence and in the absence of 2,6,8-trihydroxypurine (urate), a specific ONOO scavenger: (1) cell death; (2) specific DNA fragmentation; (3) lipid peroxidation; (4) production of RNS and ROS; (5) activity of caspase-3-like proteases; and (6) release of cytochrome from mitochondria, variations in the levels of molecular chaperones Hsp90 in the mitochondria and Hsp70 BiP in the endoplasmic reticulum (ER), and of regulatory 14-3-3 proteins in the cytosol.

Recent Applications of Chitin- and Chitosan-Based Polymers in Plants.

In recent years, the use of complex molecules based on the natural biopolymer chitin and/or on its deacetylated derivative chitosan has resulted in great advantages for many users. In particular, industries involved in the production of drugs, cosmetics, biotechnological items, and food have achieved better results using these particular molecules. In plants, chitin- and chitosan-based molecules are largely used as safe and environmental-friendly tools to ameliorate crop productivity and conservation of agronomic commodities.

Effect of Selenium on the Responses Induced by Heat Stress in Plant Cell Cultures.

High temperatures are a significant stress factor for plants. In fact, many biochemical reactions involved in growth and development are sensitive to temperature. In particular, heat stress (HS) represents a severe issue for plant productivity and strategies to obtain high yields under this condition are important goals in agriculture.

Role of peroxynitrite in the responses induced by heat stress in tobacco BY-2 cultured cells.

Temperatures above the optimum are sensed as heat stress (HS) by all living organisms and represent one of the major environmental challenges for plants. Plants can cope with HS by activating specific defense mechanisms to minimize damage and ensure cellular functionality. One of the most common effects of HS is the overproduction of reactive oxygen and nitrogen species (ROS and RNS).

Recent Advances of Chitosan Applications in Plants.

In recent years, the search for biological methods to avoid the application of chemical products in agriculture has led to investigating the use of biopolymers-based materials. Among the tested biomaterials, the best results were obtained from those based on the biopolymer chitosan (CHT). CHT, available in large quantities from the deacetylation of chitin, has multiple advantages: it is safe, inexpensive and can be easily associated with other compounds to achieve better performance.

Chitosan Effects on Plant Systems.

Chitosan (CHT) is a natural, safe, and cheap product of chitin deacetylation, widely used by several industries because of its interesting features. The availability of industrial quantities of CHT in the late 1980s enabled it to be tested in agriculture. CHT has been proven to stimulate plant growth, to protect the safety of edible products, and to induce abiotic and biotic stress tolerance in various horticultural commodities.

Reactive oxygen and nitrogen species in defense/stress responses activated by chitosan in sycamore cultured cells.

Chitosan (CHT) is a non-toxic and inexpensive compound obtained by deacetylation of chitin, the main component of the exoskeleton of arthropods as well as of the cell walls of many fungi. In agriculture CHT is used to control numerous diseases on various horticultural commodities but, although different mechanisms have been proposed, the exact mode of action of CHT is still unknown. In sycamore (Acer pseudoplatanus L.

Defense/stress responses activated by chitosan in sycamore cultured cells.

Chitosan (CHT) is a natural, non-toxic, and inexpensive compound obtained by partial alkaline deacetylation of chitin, the main component of the exoskeleton of crustaceans and other arthropods. The unique physiological and biological properties of CHT make this polymer useful for a wide range of industries. In agriculture, CHT is used to control numerous pre- and postharvest diseases on various horticultural commodities.

Ethylene is involved in stress responses induced by fusicoccin in sycamore cultured cells.

The phytohormone ethylene is involved in many physiological and developmental processes of plants, as well as in stress responses and in the development of disease resistance. Fusicoccin (FC) is a well-known phytotoxin, that in sycamore (Acer pseudoplatanus L.) cultured cells, induces a set of stress responses, including synthesis of ethylene.

Effect of heat stress on actin cytoskeleton and endoplasmic reticulum of tobacco BY-2 cultured cells and its inhibition by Co2+.

Temperature stress such as heat, cold, or freezing is a principal cause for yield reduction in crops. In particular, heat stress is very common and dangerous for plants since this stress can impact several plant and cellular functions. In spite of their role in sensing local stress and in controlling fundamental processes including PCD, the responses of cellular structures and organelles to heat stress are poorly investigated.

Role of nitric oxide in actin depolymerization and programmed cell death induced by fusicoccin in sycamore (Acer pseudoplatanus) cultured cells.

Programmed cell death (PCD) plays a vital role in plant development and is involved in defence mechanisms against biotic and abiotic stresses. Different forms of PCD have been described in plants on the basis of the cell organelle first involved. In sycamore (Acer pseudoplatanus L.

Chaperone-like activity of alpha-crystallin toward aldose reductase oxidatively stressed by copper ion.

The protective action of alpha-crystallin against copper-induced protein stress is studied using bovine lens aldose reductase (ALR2) as protein model. The oxidative inactivation of ALR2 induced by CuCl2 at the stoichiometric Cu2+/ALR2 ratio of 2/1 [I. Cecconi, M.

Fusicoccin affects cytochrome c leakage and cytosolic 14-3-3 accumulation independent of H-ATPase activation.

Fusicoccin (FC) is a well known toxin acting as a 14-3-3 protein-mediated activator of the plasma membrane H(+)-ATPase and the biochemical and physiological changes induced in the cell by this toxin have, up to now, been ascribed to the increased rate of proton extrusion by this pump leading to external acidification and cell hyperpolarization. In a recent work (Malerba M et al. 2003, Physiologia Plantarum, 119: 480-488) it was shown that, besides the previously well studied changes, FC induces a large stimulation of H(2)O(2) production, an activation of alternative respiration and a leakage of cytochrome c from mitochondria.