Biology subjects

Chaparro, A. F.

Publications and source records attributed to Chaparro, A. F..

3 recordsLinked to original sources

bioRxiv2025

Natural variation in expression of a plant immune receptor mediates elicitor sensitivity

Plant immune systems rely on pattern recognition receptors (PRRs) to specifically detect diverse pathogen/pest-associated molecular patterns (PAMPs). While many distinct receptors are known to mediate PAMP recognition, the role of transcriptional regulation of PRRs remains poorly understood. In legume plants, Inceptin Receptor (INR) senses an 11-amino acid peptide, In11, to activate direct and indirect defenses against caterpillar pests. Here we investigated the genetic basis of the rare In11 insensitivity phenotype found in common bean (Phaseolus vulgaris) landraces. Natural variation in the rapid In11-induced ethylene response corresponded with genetic variation at the locus encoding INR itself. Surprisingly, phenotypic variation corresponded with expression level of the INR receptor, rather than coding sequence variation. Promoter sequence variation across 21 accessions of Andean Phaseolus vulgaris, as well as near-isogenic lines (NILs) derived from crosses between an In11-sensitive and insensitive line, corresponded with strength of In11-induced ethylene response. Promoter alleles also corresponded with strength of activation of a luciferase reporter in the heterologous expression model, Nicotiana benthamiana, indicating that cis-element variation is sufficient to drive differences in leaf expression levels. Surprisingly, NILs encoding either WT or the lower expression inr-2 allele did not show differences in resistance to herbivory by beet armyworm (Spodoptera exigua), or in In11-pretreatment protection assays, suggesting that even low INR expression can still mediate effective responses against herbivores despite insensitivity to the In11 elicitor in laboratory assays. Our results demonstrate that natural variation in PRR expression can contribute to differential PAMP responses while not necessarily affecting downstream resistance phenotypes.

plant biology↗

bioRxiv2025

A plant immune receptor mediates tritrophic interactions by linking caterpillar detection to predator recruitment

Plants deploy direct and indirect defenses in response to insect herbivory. The specific antiherbivore responses involve cell surface immune receptors that recognize herbivore associated molecular patterns (HAMPs), yet the ecological relevance of this molecular interplay remains unexplored. We demonstrate that the Inceptin Receptor (INR) encoded by common bean, upon recognition of inceptin, a HAMP in caterpillar oral secretions, orchestrates a tritrophic interaction. Laboratory and field experimentation in Mexico using a naturally occurring inceptin-insensitive mutant and its near-isogenic wild type equivalent, revealed that inceptin recognition by INR activates an herbivore-specific immune pathway, and triggers the emission of a volatile blend that recruits predatory wasps. These findings provide a novel molecular-to-ecological link, revealing how an immune receptor mediates ecologically relevant plant-insect-predator interactions in nature.

plant biology↗

bioRxiv2021

Signatures of plant defense response specificity mediated by herbivore-associated molecular patterns in legumes

I.Chewing herbivores activate plant defense responses through a combination of mechanical wounding and elicitation by herbivore associated molecular patterns (HAMPs). HAMPs are wound response amplifiers; however, specific defense outputs may also exist that strictly require HAMP-mediated defense signaling. To investigate HAMP-mediated signaling and defense responses, we characterized cowpea transcriptome changes following elicitation by inceptin, a peptide HAMP common in Lepidoptera larvae oral secretions. Following inceptin treatment, we observed large-scale reprogramming of the transcriptome consistent with 3 different response categories: 1) amplification of mechanical wound responses, 2) temporal extension through accelerated or prolonged responses, and 3) examples of inceptin-specific elicitation and suppression. At both early and late timepoints, namely 1 and 6 hours, large sets of transcripts specifically accumulated following inceptin elicitation but not wounding alone. Further inceptin-regulated transcripts were classified as reversing changes induced by wounding alone. Within key signaling and defense related gene families, inceptin-elicited responses commonly targeted select subsets of wound-induced transcripts. Transcripts displaying the largest inceptin-elicited fold-changes included terpene synthases (TPS) and peroxidases (POX) that correspond with induced volatile production and increased peroxidase activity in cowpea. Characterization of inceptin-elicited cowpea defenses via heterologous expression in Nicotiana benthamiana demonstrated that specific cowpea TPS and POX were able to confer terpene emission and the reduced growth of beet armyworm (Spodoptera exigua) herbivores, respectively. Collectively, our present findings in cowpea support a model where HAMP-elicitation both amplifies concurrent wound responses and specifically contributes to the activation of selective outputs associated with direct and indirect anti-herbivore defenses. II. Significance StatementPlants recognize herbivore-associated molecular patterns (HAMPs) to induce defenses, but interactions with the more general wound response are not well-understood. We leveraged a known HAMP-receptor interaction to characterize transcriptomic modulation of the wound response by the peptide HAMP, inceptin. Inceptin not only amplifies wound responses, but can specifically induce or suppress transcripts with demonstrated functions in direct and indirect defense against herbivores. The plant immune system thus recognizes HAMPs to fine-tune wound responses against herbivory.

plant biology↗