Molecular characterization and expression analysis of three novel autophagy-related genes from the cattle tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae).

The cattle tick Rhipicephalus (Boophilus) microplus is a hematophagous ectoparasite of major importance for the livestock industry. It shows a remarkable ability to survive over long periods without feeding. However, the mechanisms used to endure long-term starvation are poorly understood. It is believed that autophagy, a process of intracellular protein degradation, may play a significant role to confront adverse environmental conditions. To advance our understanding of autophagy in R. microplus, in the present study we report the molecular characterization of three autophagy-related (ATG) genes, namely, RmATG3, RmATG4 and RmATG6, as well as their expression profiles in different developmental stages and organs of the parasite. The deduced amino acid sequences derived from the characterized gene sequences were subjected to Basic Local Alignment Search Tool analysis. The testing produced significant alignments with respective ATG proteins from Haemaphysalis longicornis and Ixodes scapularis ticks. Real-time polymerase chain reaction assays revealed that RmATG4 and RmATG6 transcripts were elevated in egg and ovary tissue, when compared with larva and midgut samples, while RmATG3 expression in midgut was 2-fold higher than in egg, larva and ovary samples.

Application of Seaweed Generates Changes in the Substrate and Stimulates the Growth of Tomato Plants.

Ulva ohnoi is a cosmopolitan green seaweed with commercial potential given the biomass that may be generated. We evaluated the effects of substrate changes induced by U. ohnoi application on the vegetative response of tomato plants under greenhouse conditions. First, the decomposition dynamics and N release of the dry seaweed biomass were studied using the litterbag method. Subsequently, we evaluated the effect of seaweed powder (SP) or seaweed extract (SE) applications on substrate and plant growth. Additionally, the growth parameters responses evaluated were related to the changes in substrate properties associated with each treatment. The results showed that the dry seaweed biomass has a rapid rate of degradation (k = 0.07 day-1) and N release (k = 0.024 day-1). The SP application improved the physicochemical and biological characteristics of the substrate by increasing the availability of minerals, the fungi:bacteria ratio, and the growth morphophysiological parameters (length, area, dry and fresh weight), chlorophyll and mineral content. In contrast, SE treatment showed a positive effect on the root, mineral content, and soil microbes. This study highlights the agricultural potential of U. ohnoi powder as an alternative supplement that supports nutrition and promotes the vegetative growth of plants cultivated in soilless horticultural systems.

Systemic whitefly-induced metabolic responses in newly developed distal leaves of husk tomato plants (Physalis philadelphica) impairs whiteflies development.

BACKGROUND: Metabolic reconfiguration in plants is a hallmark response to insect herbivory that occurs in the attack site and systemically in undamaged tissues. Metabolomic systemic responses can occur rapidly while the herbivore is still present and may persist in newly developed tissue to counterattack future herbivore attacks. This study analyzed the metabolic profile of local and newly developed distal (systemic) leaves of husk tomato (Physalis philadelphica) plants after whitefly Trialeurodes vaporariorum infestation. In addition, the effect of these metabolomic adjustments on whitefly oviposition and development was evaluated. RESULTS: Our results indicate that T. vaporariorum infestation induced significant changes in husk tomato metabolic profiles, not only locally in infested leaves, but also systemically in distal leaves that developed after infestation. The distinctive metabolic profile produced in newly developed leaves affected whitefly nymphal development but did not affect female oviposition, suggesting that changes driven by whitefly herbivory persist in the young leaves that developed after the infestation event to avoid future herbivore attacks. CONCLUSIONS: This report contributes to further understanding the plant responses to sucking insects by describing the metabolic reconfiguration in newly developed, undamaged systemic leaf tissues of husk tomato plants after whitefly infestation. © 2022 Society of Chemical Industry.

Physiological, Ecological, and Biochemical Implications in Tomato Plants of Two Plant Biostimulants: Arbuscular Mycorrhizal Fungi and Seaweed Extract.

The worldwide use of plant biostimulants (PBs) represents an environmentally friendly tool to increase crop yield and productivity. PBs include different substances, compounds, and growth-promoting microorganism formulations, such as those derived from arbuscular mycorrhizal fungi (AMF) or seaweed extracts (SEs), which are used to regulate or enhance physiological processes in plants. This study analyzed the physiological, ecological, and biochemical implications of the addition of two PBs, AMF or SE (both alone and in combination), on tomato plants (Solanum lycopersicum L. cv. "Rio Fuego"). The physiological responses evaluated were related to plant growth and photosynthetic performance. The ecological benefits were assessed based on the success of AMF colonization, flowering, resistance capacity, nonphotochemical quenching (NPQ), and polyphenol content. Biochemical effects were evaluated via protein, lipid, carbohydrate, nitrogen, and phosphorous content. Each PB was found to benefit tomato plants in a different but complementary manner. AMF resulted in an energetically expensive (high ETRMAX but low growth) but protective (high NPQ and polyphenol content) response. AMF + nutritive solution (NS) induced early floration but resulted in low protein, carbohydrate, and lipid content. Both AMF and AMF + NS favored foliar instead of root development. In contrast, SE and SE + NS favored protein content and root development and did not promote flowering. However, the combination of both PBs (AMF + SE) resulted in an additive effect, reflected in an increase in both foliar and root growth as well as protein and carbohydrate content. Moreover, a synergistic effect was also found, which was expressed in accelerated flowering and AMF colonization. We present evidence of benefits to plant performance (additive and synergistic) due to the interactive effects between microbial (AMF) and nonmicrobial (SEs) PBs and propose that the complementary modes of action of both PBs may be responsible for the observed positive effects due to the new and emerging properties of their components instead of exclusively being the result of known constituents. These results will be an important contribution to biostimulant research and to the development of a second generation of PBs in which combined and complementary mechanisms may be functionally designed.