Plant responses to multiple antagonists are mediated by order of attack and phytohormone crosstalk

Plants are often attacked by multiple antagonists, and traits of the attacking organisms, and their order of arrival onto hosts, may affect plant defenses. However, few studies have assessed how multiple antagonists, and varying attack order, affect plant defense or nutrition. To address this, we assessed defensive and nutritional responses of Pisum sativum plants after attack by a vector herbivore (Acrythosiphon pisum), a non-vector herbivore (Sitona lineatus), and a pathogen (Pea enation mosaic virus, PEMV). We show PEMV-infectious A. pisum induced several pathogen-specific plant defense signals, but these defenses were inhibited when S. lineatus was present in peas infected with PEMV. In contrast, feeding by S. lineatus induced anti-herbivore defense signals, but these defenses were enhanced by PEMV. Sitonalineatus also increased abundance of plant amino acids, but only when they attacked after PEMV-infectious A. pisum. Our results suggest that diverse communities of biotic antagonists alter defense and nutritional traits of plants through complex pathways that depend on the identity of attackers and their order of arrival onto hosts. Moreover, we show interactions among a group of biotic stressors can vary along a spectrum from antagonism to enhancement/synergism based on the identity and order of attackers, and these interactions are mediated by a multitude of phytohormone pathways.

Plant responses to multiple antagonists are mediated by order of attack and phytohormone crosstalk

Plants are often attacked by multiple antagonists, and traits of the attacking organisms, and their order of arrival onto hosts, may affect plant defenses. However, few studies have assessed how multiple antagonists, and varying attack order, affect plant defense or nutrition. To address this, we assessed defensive and nutritional responses of Pisum sativum plants after attack by a vector herbivore (Acrythosiphon pisum), a non-vector herbivore (Sitona lineatus), and a pathogen (Pea enation mosaic virus, PEMV). We show PEMV-infectious A. pisum induced several pathogen-specific plant defense signals, but these defenses were inhibited when S. lineatus was present in peas infected with PEMV. In contrast, feeding by S. lineatus induced anti-herbivore defense signals, but these defenses were enhanced by PEMV. Sitona lineatus also increased abundance of plant amino acids, but only when they attacked after PEMV-infectious A. pisum. Our results suggest that diverse communities of biotic antagonists alter defense and nutritional traits of plants through complex pathways that depend on the identity of attackers and their order of arrival onto hosts. Moreover, we show interactions among a group of biotic stressors can vary along a spectrum from antagonism to enhancement/synergism based on the identity and order of attackers, and these interactions are mediated by a multitude of phytohormone pathways.

INFLUENCE OF NPK MINERALS AND BIOSTIMULANTS ON THE GROWTH, YIELD, AND FRUIT NUTRITIONAL VALUE IN CV. ‘ŠAMPION’ APPLE TREES GROWING ON DIFFERENT ROOTSTOCKS

The study was conducted in 2015–2017 to assess the influence of rootstocks on the growth and fruiting of apple trees of cv.‘Šampion’ cultivated on rootstocks M26, P2. M9, and P22 with the following treatments: mineral fertilization (NPK), nano-concentrations of elements (Fe, Co, Al, Mg, Mn, Ni, Ag), natural chicken manure fertiliser, humus, microbial product, plant amino acids, and stillage yeasts. ‘Šampion’ apple trees grew vigorously on rootstocks M26 and P2 when humus and microbiological biostimulants were applied, especially in terms of the shoot diameter and TCSA. The best fruit yield and quality parameters were obtained in apple trees growing on rootstocks M9 and M26 fertilised with microbiological biostimulants and formulations containing plant amino acids. Apples with the highest concentration of nutrients, in particular minerals, were harvested from trees growing on rootstocks M9 and P22 and stimulated with nanoparticle mineral preparations and humus formulations.

Determination of qualitative composition and quantitative content of amino acids in garlic bulbs and leaves

Introduction. Plant amino acids have an important impact on functioning of various systems and organs of human body. In addition, they possess a wide range of pharmacotherapeutic properties, improve the digestion and potentiate the activity of biologically active compounds present in plants. Thus, the search of plant species that contain a large complex of plant amino acids and are used as food is of current interest. Garlic (Allium sativum L.) from Alliaceae family is one of such plants, and has been used since ancient times for the treatment of various disorders.The aim of the study – to determine the composition and quantitative content of free and bound amino acids of garlic bulbs and leaves.Research methods. The amino acid composition was determined using the high-performance liquid chromatography (HPLC) method.Results and Discussion. 16 amino acids were detected in garlic bulbs as a result of the experiment. Arginine (3.04 %) and proline (1.56 %) were found to be accumulated infree state, while glutamic acid (10.59 %), aspartic acid (6.06 %) and arginine (5.94 %) prevailed in bound state. 15 free and 16 bound amino acids were identified and quantified in garlic leaves. Glutamic acid (2.11 %), leucine (1.79 %), valine (1.77 %), isoleucine (1.52 %), treonine and phenylalanine (1.44 %) dominated infree state, and glutamic acid (28.49 %), aspartic acid (12.90 %) and leucine (7.61 %) prevailed in bound state. Methionine was found only in bound state in garlic leaves.Conclusions. The amino acid composition of garlic bulbs and leaves was studied using the HPLC method. 16 amino acids in both free and bound state were detected and their content was determined in garlic bulbs, while in garlic leaves – 15 free and 16 bound amino acids. The results of the experiment showed that methionine is present only in bound state in garlic leaves.