Biology subjects

Escobar-Bravo, R.

Publications and source records attributed to Escobar-Bravo, R..

3 recordsLinked to original sources

bioRxiv2023

The benzoxazinoid breakdown product 5-Methoxy-2-Nitrophenol has a dual function in maize defense against herbivory

Catabolism of plant secondary metabolites can yield bioactive breakdown products. However, these compounds often remain poorly characterized. Here, we report on the discovery, biosynthesis, and biological relevance of 5-Methoxy-2-Nitrophenol (5M2NP), a secondary metabolite breakdown product which accumulates in damaged maize tissues. We used mutant plants, biochemical complementation, and metabolomic analyses to determine the biosynthetic origin of 5M2NP. Additionally, we assessed 5M2NPs role in plant defense against herbivores. For this, we surveyed defense-associated responses (gene expression, phytohormones, volatile organic compounds) in wounded, 5M2NP-supplemented maize leaves, and performed bioassays with herbivorous insects. We found that 5M2NP accumulation upon tissue disruption is contingent upon a functional benzoxazinoid biosynthesis pathway. Labeling experiments demonstrated that 5M2NP is derived from DIMBOA. Physiological doses of exogenous 5M2NP increased the wound-induced expression of defense genes and emission of terpenoids. Additionally, 5M2NP exhibited antibiotic and antixenotic activities towards both generalist and specialist herbivores in nano-to micromolar quantities. We conclude that 5M2NP, which represents a novel class of plant-derived compounds, can act as a direct defense and a defense modulator. 5M2NP thus expands the functional repertoire of benzoxazinoids and likely contributes to their protective function against insect herbivores. The discovery of 5M2NP highlights the multifunctionality of plant secondary metabolites and their breakdown products.

plant biology↗

bioRxiv2022

Maize integrates light and volatile cues from neighboring plants into unique defense responses

Plants perceive the presence and defense status of their neighbors through light and volatile cues, but how plants integrate both stimuli is poorly understood. We investigated if and how low Red to Far red light (R:FR) ratios, indicative of shading or canopy closure, affect maize (Zea mays) responses to herbivore-induced plant volatiles (HIPVs), including the green leaf volatile (Z)-3-hexenyl acetate. We modulated light signaling and perception by using FR supplementation and a phyB1phyB2 mutant, and we determined volatile release as a response readout. To gain mechanistic insights, we examined expression of volatile biosynthesis genes, hormone accumulation, and photosynthesis. Exposure to a full blend of HIPVs or (Z)-3-hexenyl acetate induced maize volatile release. Short-term FR supplementation increased this response. In contrast, prolonged FR supplementation or constitutive phytochrome B inactivation in phyB1phyB2 plants showed the opposite response. Short-term FR supplementation enhanced photosynthesis and stomatal conductance and (Z)-3-hexenyl acetate-induced JA-Ile levels. We conclude that a FR-enriched light environment can prompt maize plants to respond more strongly to HIPVs emitted by neighbors, which might be explained by changes in photosynthetic processes and phytochrome B signaling. Our findings reveal interactive responses to light and volatile cues with potentially important consequences for plant-plant and plant-herbivore interactions.

plant biology↗

bioRxiv2020

Leafminer attack induces plant-mediated facilitation of conspecific pupae in the soil

O_LIHerbivore population dynamics are strongly influenced by the interactions established through their shared host. Such plant-mediated interactions can occur between different herbivore species and between different life developmental stages of the same herbivore. Yet, whether these interactions occur between leaf-feeding herbivores and their soil-dwelling pupae is unknown. C_LIO_LIWe studied whether tomato (Solanum lycopersicum) leaf-herbivory by the American serpentine leafminer Lyriomiza trifolii affects the performance of conspecific pupae in the soil adjacent to the plant. To gain mechanistic insights, we performed insect bioassays with the jasmonate-deficient tomato mutant def-1 and its wild type, along with the analysis of phytohormones, gene expression and root volatiles. C_LIO_LILeafminer metamorphosis in the soil was accelerated when wild type plants were attacked aboveground by conspecifics, but the opposite was observed in def-1. Changes in pupal developmental rate were mediated by belowground volatiles. Accordingly, leafminer herbivory differentially modulated jasmonate and abscisic acid signaling and the accumulation of specific volatiles in the roots of wild type versus def-1 plants C_LIO_LIOur results demonstrate that aboveground herbivores can facilitate their soil-dwelling pupae by inducing def-1-dependent systemic responses. This study expands the repertoire of plant-herbivore interactions to herbivory-induced modulation of metamorphosis, with potentially important consequences for plant and herbivore community dynamics. C_LI

plant biology↗