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The Influence of Lead and Acyrthosiphon pisum (Harris) on Generation of Pisum sativum Defense Signaling Molecules and Expression of Genes Involved in Their Biosynthesis
The main aim of this study was to understand the regulation of the biosynthesis of phytohormones as signaling molecules in the defense mechanisms of pea seedlings during the application of abiotic and biotic stress factors. It was important to identify this regulation at the molecular level in Pisum sativum L. seedlings under the influence of various concentrations of lead—i.e., a low concentration increasing plant metabolism, causing a hormetic effect, and a high dose causing a sublethal effect—and during feeding of a phytophagous insect with a piercing-sucking mouthpart—i.e., pea aphid (Acyrthosiphon pisum (Harris)). The aim of the study was to determine the expression level of genes encoding enzymes of the biosynthesis of signaling molecules such as phytohormones—i.e., jasmonates (JA/MeJA), ethylene (ET) and abscisic acid (ABA). Real-time qPCR was applied to analyze the expression of genes encoding enzymes involved in the regulation of the biosynthesis of JA/MeJA (lipoxygenase 1 (LOX1), lipoxygenase 2 (LOX2), 12-oxophytodienoate reductase 1 (OPR1) and jasmonic acid-amido synthetase (JAR1)), ET (1-aminocyclopropane-1-carboxylate synthase 3 (ACS3)) and ABA (9-cis-epoxycarotenoid dioxygenase (NCED) and aldehyde oxidase 1 (AO1)). In response to the abovementioned stress factors—i.e., abiotic and biotic stressors acting independently or simultaneously—the expression of the LOX1, LOX2, OPR1, JAR1, ACS3, NCED and AO1 genes at both sublethal and hormetic doses increased. Particularly high levels of the relative expression of the tested genes in pea seedlings growing at sublethal doses of lead and colonized by A. pisum compared to the control were noticeable. A hormetic dose of lead induced high expression levels of the JAR1, OPR1 and ACS3 genes, especially in leaves. Moreover, an increase in the concentration of phytohormones such as jasmonates (JA and MeJA) and aminococyclopropane-1-carboxylic acid (ACC)-ethylene (ET) precursor was observed. The results of this study indicate that the response of pea seedlings to lead and A. pisum aphid infestation differed greatly at both the gene expression and metabolic levels. The intensity of these defense responses depended on the organ, the metal dose and direct contact of the stress factor with the organ.
In Memoriam: Professor Philippe Jeandet – an outstanding scientist and his legacy in natural product chemistry and bioactivity
Professor Philippe Jeandet was one of the world’s leading biologists and plant biochemists, best known for his research on the chemical structure of natural products and their bioactivity, particularly that of stilbenoids. His scientific interests primarily focused on resveratrol (trans-3,5,4'-trihydroxystilbene), a stilbene with a wide range of biological activities. Additionally, his work highlighted the potential of combining pharmacological treatments with the use of natural products of plant origin, which have made significant contributions to the treatment of various diseases. He leaves behind a legacy of groundbreaking research and a lasting influence in the field. He was also involved in research on sugar signaling during plant responses to abiotic and biotic stress factors, as well as the role of signaling molecules in fruit development. His scientific achievements demonstrate that he was, first and foremost, a dedicated scientist – but also a honourable colleague who understood and respected the work of others.