Biology subjects

Laxalt, A. M.

Publications and source records attributed to Laxalt, A. M..

3 recordsLinked to original sources

bioRxiv2025

Phosphoinositide-specific Phospholipase C 2 (SlPLC2) Facilitates Vesicle Formation and Modulates Immune Signaling in Tomato Phytophthora infestans Interactions

Phosphoinositide-specific phospholipase C (PI-PLC) is a signaling enzyme that hydrolyzes membrane phosphoinositide to generate lipid- and lipid-derived second messengers. In plants, PI-PLCs have been implicated in various physiological processes, including immunity. Tomato SlPLC2 was previously shown to be implicated in susceptibility to the necrotrophic fungus Botrytis cinerea. However, whether this observation extends to pathogens with different lifestyles and evolutionary origins, remains unknown. Here, we investigated SlPLC2 function during infection with Phytophthora infestans, a globally devastating oomycete and causal agent of potato and tomato late blight. CRISPR-Cas9 knockout SlPLC2 plants showed significantly reduced disease symptoms, lower pathogen biomass, and decreased sporangia production, indicating impaired colonization. Upon infection, SlPLC2 knockout lines displayed attenuated expression of salicylic acid (SA)- and jasmonic acid (JA)-responsive genes suggesting disrupted hormone signaling. Consistent with PLC role during plant defense, early immune responses such as hydrogen peroxide accumulation and callose deposition were reduced in knockout plants. At the cellular level, these plants allow fewer infection vesicles formation by P. infestans, accompanied by an increase in expression of a biotrophy-associated effector gene PiAvrblb2, suggesting impaired establishment of infection. In Nicotiana benthamiana SlPLC2-GFP localizes predominantly at the plasma membrane. Upon P. infestans inoculations, SlPLC2-GFP localizes to the membrane surrounding infection vesicles, where we also detected phosphoinositides PI4P and PI(4,5)P2. Overexpression of SlPLC2 in Nicotiana benthamiana enhanced susceptibility to P. infestans, reinforcing its positive role in colonization. Together, these findings identify SlPLC2 as a susceptibility factor associated with enhanced P. infestans colonization. StatementThis study identifies SlPLC2 as a key susceptibility factor that supports Phytophthora infestans infection by coordinating vesicle formation and early immune responses in tomato.

plant biology↗

bioRxiv2020

Exogenous Nitro-Oleic Acid inhibits primary root growth by reducing the mitosis in the meristem in Arabidopsis thaliana

Nitric oxide (NO) is a second messenger that regulates a broad range of physiological processes in plants. NO-derived molecules called reactive nitrogen species (RNS) can react with unsaturated fatty acids generating nitrated fatty acids (NO2-FA). NO2-FA work as signaling molecules in mammals where production and targets have been described under different stress conditions. Recently, NO2-FAs were detected in plants, however their role(s) on plant physiological processes is still poorly known. Here we show that exogenous application of nitro-oleic acid (NO2-OA) inhibits Arabidopsis primary root growth; this inhibition is not likely due to nitric oxide (NO) production or impaired auxin or cytokinin root responses. Deep analyses showed that roots incubated with NO2-OA had a lower cell number in the division area. Although this NO2-FA did not affect the signaling mechanisms maintaining the stem cell niche, plants incubated with NO2-OA showed a reduction of cell division in the meristematic area. Therefore, this work shows that NO2-OA inhibits mitotic processes subsequently reducing primary root growth.

plant biology↗

bioRxiv2018

Nitro-Oleic Acid Induced Reactive Oxygen Species Formation and Plant Defense Signaling in Tomato Cell Suspensions

Nitrated fatty acids (NO2-FAs) are formed by the addition reaction of nitric oxide- and nitrite-derived nitrogen dioxide with unsaturated fatty acids. Nitrated fatty acids act as signaling molecules in mammals through the formation of covalent adducts with cellular thiols. The study of NO2-FAs in plant systems constitutes an interesting and emerging area. The presence of NO2-FA has been reported in olives, peas, rice and in Arabidopsis. To gain a better understanding of the role of NO2-FA on plant physiology, we analyzed the effects of exogenous application of nitro-oleic acid (NO2-OA) to tomato cell cultures. We found that NO2-OA induced reactive oxygen species (ROS) production in a dose-dependent manner via activation of NADPH oxidases, which requires calcium entry from the extracellular compartment and protein kinase activation, a mechanism that resembles the plant defense responses. NO2-OA-induced ROS production, expression of plant defense genes and led to cell death. The mechanism of action of NO2-OA involves a reduction in the glutathione cellular pool and covalently addition reactions with protein thiols and reduced glutathione. Altogether, these results indicate that NO2-OA triggers responses associated with plant defense, revealing its possible role as a signal molecule in biotic stress.\n\nAbbreviations

plant biology↗