Jasmonic Acid Pathway in Plants 2.0

The plant hormone jasmonic acid (JA) and its derivative, an amino acid conjugate of JA (jasmonoyl isoleucine: JA-Ile), are signaling compounds involved in the regulation of cellular defense and development in plants [...]

On the Applicability of Chitosan Oligomers-Amino Acid Conjugate Complexes as Eco-Friendly Fungicides against Grapevine Trunk Pathogens

In a context in which the incidence and severity of grapevine fungal diseases is increasing as a result of both climate change and modern management culture practices, reducing the excessive use of phytosanitary products in viticulture represents a major challenge. Specifically, grapevine trunk diseases (GTDs), caused by several complexes of wood decay or xylem-inhabiting fungi, pose a major challenge to vineyard sustainability. In this study, the efficacy of chitosan oligomers (COS)–amino acid conjugate complexes against three fungal species belonging to the Botryosphaeriaceae family (Neofusicoccum parvum, Diplodia seriata, and Botryosphaeria dothidea) was investigated both in vitro and in planta. In vitro tests led to EC50 and EC90 effective concentrations in the 254.6−448.5 and 672.1−1498.5 µg·mL−1 range, respectively, depending on the amino acid involved in the conjugate complex (viz. cysteine, glycine, proline or tyrosine) and on the pathogen assayed. A synergistic effect between COS and the amino acids was observed against D. seriata and B. dothidea (synergy factors of up to 2.5 and 2.8, respectively, according to Wadley’s method). The formulations based on COS and on the conjugate complex that showed the best inhibition rates, COS−tyrosine, were further investigated in a greenhouse trial on grafted vines of two varieties (”Tempranillo” on 775P and “Garnacha” on 110R rootstock), artificially inoculated with the mentioned three Botryosphaeriaceae species. The in planta bioassay revealed that the chosen formulations induced a significant decrease in disease severity against N. parvum and B. dothidea. In summary, the reported conjugate complexes may be promising enough to be worthy of additional examination in larger field trials.

Microwave-Induced Ugi-Four Component Reactions: Synthesis of New Hetero- Steroid-Amino Acid Conjugates

Background: Aza-steroids are an important class of compounds because of their numerous biological activities. The hetero steroids have different hydrogen bonding ability and hydrophobicity in comparison to steroids. Materials and Methods: Microwave-induced synthesis of a novel type of hybrid hetero-steroid amine conjugates, following Ugi-four component reactions of steroidal amines with alanine and valine methyl esters as amino acid residues is described. Specifically, hetero-steroid-amino acid conjugate based on D-ring fused hetero steroidal amine, hetero-steroid-amino acid conjugate based on A-ring hetero steroidal amine, and hetero-steroidamino acid conjugate based on B-ring hetero steroidal amine are synthesized. Results and Discussion: The yield of the products under microwave-induced process was considerably higher than that obtained by the conventional method. In contrast to the conventional method for the synthesis of these molecules, microwave-induced method has several advantages. Conclusion: These include rapid reaction, a superior yield of the product, minimum side reaction, and economical microwave-induced process.

Antifungal Activity of Chitosan Oligomers–Amino Acid Conjugate Complexes against Fusarium culmorum in Spelt (Triticum spelta L.)

Fusarium head blight (FHB) is a complex disease of cereals caused by Fusarium species, which causes severe damages in terms of yield quality and quantity worldwide, and which produces mycotoxin contamination, posing a serious threat to public health. In the study presented herein, the antifungal activity against Fusarium culmorum of chitosan oligomers (COS)–amino acid conjugate complexes was investigated both in vitro and in vivo. The amino acids assayed were cysteine, glycine, proline and tyrosine. In vitro tests showed an enhancement of mycelial growth inhibition, with EC50 and EC90 effective concentration values ranging from 320 to 948 µg·mL−1 and from 1107 to 1407 µg·mL−1 respectively, for the conjugate complexes, as a result of the synergistic behavior between COS and the amino acids, tentatively ascribed to enhanced cell membrane damage originating from lipid peroxidation. Tests on colonies showed a maximum percentage reduction in the number of colonies at 1500 µg·mL−1 concentration, while grain tests were found to inhibit fungal growth, reducing deoxynivalenol content by 89%. The formulation that showed the best performance, i.e., the conjugate complex based on COS and tyrosine, was further investigated in a small-scale field trial with artificially inoculated spelt (Triticum spelta L.), and as a seed treatment to inhibit fungal growth in spelt seedlings. The field experiment showed that the chosen formulation induced a decrease in disease severity, with a control efficacy of 83.5%, while the seed tests showed that the treatment did not affect the percentage of germination and resulted in a lower incidence of root rot caused by the pathogen, albeit with a lower control efficacy (50%). Consequently, the reported conjugate complexes hold enough promise for crop protection applications to deserve further examination in larger field trials, with other Fusarium spp. pathogens and/or Triticum species.

Jasmonic Acid: An Essential Plant Hormone

The plant hormone jasmonic acid (JA) and its derivative, an amino acid conjugate of JA (jasmonoyl isoleucine: JA-Ile), are signaling compounds involved in the regulation of cellular defense and development in plants [...]

Identification of an indole–triazole–amino acid conjugate as a highly effective antifungal agent

Compounds constructed by the grafting of amino acid and triazole with an indole moiety were synthesized and investigated for antifungal activities wherein one of the compounds gave highly promising results.

Remarkable isomer-selective gelation of aromatic solvents by a polymorph of a urea-linked bile acid–amino acid conjugate

A urea-linked bile acid–amino acid conjugate was developed as a remarkable isomer-selective gelator for various disubstituted aromatic solvents. Polymorphism shown by the urea derivative was studied in detail which showed that only the amorphous polymorph acts as a gelator, but not the crystalline one.