Physio-molecular responses of tomato cultivars to biotic stress: Exploring the interplay between Alternaria alternata OP881811 infection and plant defence mechanisms.

Plant fungal diseases impose a formidable challenge for global agricultural productivity, a meticulous examination of host-pathogen interactions. In this intricate study, an exhaustive investigation was conducted on infected tomatoes obtained from Egyptian fields, leading to the precise molecular identification of the fungal isolate as Alternaria alternata (OP881811), and the isolate showed high identity with Chinese isolates (ON973896 and ON790502). Subsequently, fourteen diverse tomato cultivars; Cv Ferment, Cv 103, Cv Damber, Cv 186, Cv 4094, Cv Angham, Cv N 17, Cv Gesma, Cv 010, Cv branch, cv 2020, Cv 023, Cv Gana and Cv 380 were meticulously assessed to discern their susceptibility levels upon inoculation with Alternaria alternata. Thorough scrutiny of disease symptom manifestation and the extent of tomato leaf damage ensued, enabling a comprehensive evaluation of cultivar responses. Results unveiled a spectrum of plant susceptibility, with three cultivars exhibiting heightened vulnerability (Cv Ferment, Cv 103 and Cv Damber), five cultivars displaying moderate susceptibility (Cv 186, Cv 4094, Cv Angham, Cv N 17 and Cv Gesma), and six cultivars demonstrating remarkable resilience to the pathogen (Cv 010, Cv branch, cv, 2020; Cv 023, Cv Gana and Cv 380). In order to gain a thorough understanding of the underlying physiological patterns indicative of plant resistance against A. alternata, an in-depth exploration of polyphenols, flavonoids, and antioxidant enzymes ensued. These key indicators were closely examined, offering valuable insights into the interplay between plant physiology and pathogen response. Robust correlations emerged, with higher contents of these compounds correlating with heightened susceptibility, while lower levels were indicative of enhanced plant tolerance. In tandem with the physiological assessment, a thorough investigation of four pivotal defensive genes (PR5, PPO, PR3, and POX) was undertaken, employing cutting-edge Real-Time PCR technology. Gene expression profiles displayed intriguing variations across the evaluated tomato cultivars, ultimately facilitating the classification of cultivars into distinct groups based on their levels of resistance, moderate susceptibility, or heightened sensitivity. By unravelling the intricate dynamics of plant susceptibility, physiological responses, and patterns of gene expression, this comprehensive study paves the way for targeted strategies to combat plant fungal diseases. The findings contribute valuable insights into host-pathogen interactions and empower agricultural stakeholders with the knowledge required to fortify crop resilience and safeguard global food security.

Phytochemical analysis and insight into insecticidal and antifungal activities of Indian hawthorn leaf extract.

Fungicides or insecticides are popular means of controlling a variety of pathogens and insect pests; however, they can cause harmful effects on both human health and the environment. Different researchers have suggested using plant extracts, which have shown promise in managing fungi and insects. The purpose of this investigation was to explore the antifungal activities of an acetone extract made from the leaves of Indian Hawthorn (HAL) against phytopathogens that are known to harm maize crops, Fusarium verticillioides (OQ820154) and Rhizoctonia solani (OQ820155), and to evaluate the insecticidal property against Aphis gossypii Glover aphid. The HAL extract demonstrated significant antifungal activity against the two fungal pathogens tested, especially at the high dose of 2000 µg/mL. Laboratory tests on the LC20 of HAL extract (61.08 mg/L) versus buprofezin 25% WP (0.0051 mg/L) were achieved on A. gossypii Glover. HAL extract diminished the nymph's production over 72 h and their total reproductive rate. This extract was like buprofezin 25% WP in decreasing the daily reproductive rate, reproductive period, and mean survival percentage. Nevertheless, the newly-born nymphs of treated females with HAL extract attained the highest reduction in survival percentage at 46.00%. Equalized prolongations on the longevity of nymphs to 9.33, 8.33, and 7 days and the total life cycle to 15.00, 14.00, and 12.67 days were realized by HAL extract, buprofezin 25% WP, and the control, respectively. The olfactory choice test on the aphids showed the minimum attraction rate to HAL extract. The HPLC of HAL extract comprised an abundance of phenolic compounds (ferulic acid, gallic acid, 4-hydroxybenzoic acid, salicylic acid, ellagic acid, and pyrogallol), and the concentrations of these compounds vary widely, with salicylic acid being the most concentrated at 25.14 mg/mL. Among the flavonoids, epicatechin has the highest concentration at 11.69 mg/mL. The HAL extract GC-MS consists of various organic compounds, including sesquiterpenes, cyclopropenes, fatty acids, steroids, alcohols, ketones, esters, bufadienolides, opioids, and other organic compounds. The most abundant compounds in the sample are n-hexadecanoic acid (12.17%), followed by 5α, 7αH, 10α-eudesm-11-en-1α-ol (9.43%), and cis-13-octadecenoic acid (5.87%). Based on the findings, it can be inferred that the HAL extract may be a viable option for plants to combat both fungal and insect infestations. This presents an encouraging prospect for utilizing a natural and sustainable approach toward long-term pest management in plants.