Interaction between Signal Pathways upon Formation of Plant Defense in Response to Environmental Stress Factors

In the course of evolution, plants have developed numerous specific regulatory signal pathways, which are hormonal for the most part. Phytohormones comprise not only such generally recognized endogenous growth regulators as abscisic acid, auxins, cytokinins, gibberellins, brassinosteroids (BS), ethylene, salicylic acid (SA), and jasmonates but also recently described derivatives of apocarotenoids—strigolactones (SL). Signal pathways interact at the level of biosynthesis of messengers and their translocation as well as upon activation of target genes. Since abiotic and biotic environmental stressors negatively influence plant productivity, understanding of molecular mechanisms of regulation induced by stress agents may help researchers to produce stress-resistant and high-yielding plants using molecular techniques. This paper is a review of present-day literature dealing with the interaction and interference of nonhormonal and hormonal signals regulating growth and development of plants under ever-changing environmental conditions.

Glutathione Status in the Roots of Tomato Plants Transgenic by Genes psl and rapA1 in the Presence of Rhizobium leguminosarum

The level of glutathione was investigated in the roots of tomato (Solanum lycopersicum L.) plants transgenic by genes psl and rapA1 in the presence of a microsymbiont of leguminous plants Rhizobium leguminosarum VSy3. The plants transformed with gene psl showed a greater bacterial adhesion than the plants transformed with gene rapA1, which positively correlated with growth parameters of plants. Treatment with rhizobia elevated the content of glutathione in the roots of wild type plants three times, 4.7 times in the roots of plants transformed with gene rapA1, and more than five times in the plants transgenic by gene psl. The obtained results suggest that the level of glutathione in the roots may serve as a marker of efficiency of artificial symbiotic systems produced de novo.