Biology subjects

Arbona, V.

Publications and source records attributed to Arbona, V..

4 recordsLinked to original sources

bioRxiv2023

Stomata, a vulnerability in the plant defence against phytophagous mites that ABA can overcome

Arthropod herbivory possess a significant threat to crop yield, prompting plants to employ intricate defense mechanisms against pest feeding. The generalist pest, Tetranychus urticae, inflicts rapid damage and remains a challenge due to its broad target range. In this study, we explored Arabidopsis thalianas response to T. urticae infestation, revealing the induction of abscisic acid (ABA), a hormone typically associated with abiotic stress adaptation, including stomatal closure during water stress. Leveraging a FRET-based ABA biosensor (nlsABACUS2-400n), we observed elevated ABA levels in various leaf cell types post-mite feeding. While ABAs role in pest resistance or susceptibility has been debated, an ABA-deficient mutant exhibited increased mite infestation, alongside intact canonical biotic stress signalling, indicating an independent function of ABA in mite defense. Through genetic and pharmacological interventions targeting ABA levels, ABA signalling, stomatal aperture, and density, we established that ABA-triggered stomatal closure effectively hinders mite feeding and minimizes leaf cell damage. This study underscores the critical interplay between biotic and abiotic stresses in plants, highlighting how the vulnerability to mite infestation arising from open stomata, crucial for transpiration and photosynthesis, underscores the intricate relationship between these two stress types.

plant biology↗

bioRxiv2023

Specific ABA-independent tomato transcriptome reprogramming under abiotic stress combination

Crops often have to face several abiotic stresses simultaneously, and under these conditions, the plants response significantly differs from that observed under a single stress. Nevertheless, most of the molecular markers identified for increasing plant stress tolerance have been characterized under single abiotic stresses, explaining their unexpected results when they are tested under real field conditions. One important regulator of the plants responses to abiotic stresses is ABA. The ABA signaling system engages many stress-responsive genes, however, many others do not respond to ABA treatments. Thus, the ABA-independent pathway, which is still largely unknown, involve multiple signaling pathways and important molecular components necessary for the plants adaptation to climate change. In the present study, tomato ABA-deficient mutants (flacca, flc) were subjected to salinity, heat, or their combination. A deep RNA-seq analysis revealed that the combination of salinity and heat induced an important reprogramming of the tomato transcriptome, and from the 685 genes that were specifically regulated under this combination in our flc mutants, 463 genes were regulated by ABA-independent systems. Among these genes, we identified 6 transcription factors (TFs) belonging to the R2R3MYB family that were significantly upregulated. A protein-protein interaction network showed that the TFs SlMYB50 and SlMYB86 were directly involved in the upregulation of the flavonol biosynthetic pathway-related genes. This is the first time that some important ABA-independent TFs involved in the specific plant response to abiotic stress combination have been identified. Considering that ABA levels dramatically change in response to environmental factors, the study of ABA-independent genes that are specifically regulated under stress combination may provide a marvelous tool for increasing plant resilience to climate change. SIGNIFICANCE STATEMENTThis study in tomato Wt and ABA-deficient mutant plants reveals a specific and unique ABA-independent transcriptome reprogramming under abiotic stress combination, with the identification of some key TFs that were induced under these specific conditions. Taking into account that ABA levels dramatically change in all crops in response to environmental factors, the study of ABA-independent genes that are specifically regulated under stress combination may provide a marvelous tool for increasing plant resilience to climate change.

plant biology↗

bioRxiv2021

Coordination between growth and stress responses by DELLA in the liverwort Marchantia polymorpha

Plant survival depends on the optimal use of resources under variable environmental conditions. Among the mechanisms that mediate the balance between growth, differentiation and stress responses, the regulation of transcriptional activity by DELLA proteins stands out. In angiosperms, DELLA accumulation promotes defense against biotic and abiotic stress and represses cell division and expansion, while loss of DELLA function is associated with increased plant size and sensitivity towards stress1. Given that DELLA protein stability is dependent on gibberellin (GA) levels2, and GA metabolism is influenced by the environment3, this pathway is proposed to relay environmental information to the transcriptional programs that regulate growth and stress responses in angiosperms4,5. However, DELLA genes are also found in bryophytes, whereas canonical GA receptors appeared only in vascular plants6-10. Thus, it is not clear whether these regulatory functions of DELLA predated or emerged with typical GA signaling. Here we show that, as in vascular plants, the only DELLA in the liverwort Marchantia polymorpha also participates in the regulation of growth and key developmental processes, and promotes the tolerance towards oxidative stress. Moreover, part of these effects is likely caused by the conserved physical interaction with the MpPIF transcription factor. Therefore, we suggest that the role in the coordination of growth and stress responses was already encoded in DELLA from the common ancestor of land plants, and the importance of this function is justified by its conservation over the past 450 M years.

plant biology↗

bioRxiv2020

The generalist herbivore Tetranychus urticae (Koch) adapts to novel plant hosts through rapid evolution of metabolic resistance

Genetic adaptation, occurring over a long evolutionary time, enables host-specialized herbivores to develop novel resistance traits and to efficiently counteract the defenses of a narrow range of host plants. In contrast, physiological acclimation, leading to the suppression and/or detoxification of host defenses is hypothesized to enable broad-generalists to shift between plant hosts. However, the host adaptation mechanisms used by generalists composed of host-adapted populations are not known. Tetranychus urticae is an extreme generalist herbivore whose individual populations perform well only on a subset of potential hosts. We combined experimental evolution, Arabidopsis genetics, mite reverse genetics, and pharmacological approaches to examine mite host adaptation upon the shift of a bean-adapted population to Arabidopsis thaliana. We showed that cytochrome P450 monooxygenases are required for mite adaptation to Arabidopsis. We identified activities of two tiers of P450s: general xenobiotic-responsive P450s that have a limited contribution to mite adaptation to Arabidopsis and adaptation-associated P450s that efficiently counteract Arabidopsis defenses. In {approx}25 generations of mite selection on Arabidopsis plants, mites evolved highly efficient detoxification-based adaptation, characteristic of specialist herbivores. This demonstrates that specialization to plant resistance traits can occur within the ecological timescale, enabling the two-spotted spider mite to shift to novel plant hosts.

evolutionary biology↗