DSpace Angular :: Browsing by Author "Meneses Araya, Claudio Antonio"

Browsing by Author "Meneses Araya, Claudio Antonio"

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A First Insight into the Microbial and Viral Communities of Comau Fjord-A Unique Human-Impacted Ecosystem in Patagonia (42 degrees S)
(2023) Guajardo Leiva, Sergio Eduardo; Mendez, Katterinne N.; Meneses Araya, Claudio Antonio; Diez Moreno, Beatriz; Castro Nallar, Eduardo
While progress has been made in surveying the oceans to understand microbial and viral communities, the coastal ocean and, specifically, estuarine waters, where the effects of anthropogenic activity are greatest, remain partially understudied. The coastal waters of Northern Patagonia are of interest since this region experiences high-density salmon farming as well as other disturbances such as maritime transport of humans and cargo. Here, we hypothesized that viral and microbial communities from the Comau Fjord would be distinct from those collected in global surveys yet would have the distinctive features of microbes from coastal and temperate regions. We further hypothesized that microbial communities will be functionally enriched in antibiotic resistance genes (ARGs) in general and in those related to salmon farming in particular. Here, the analysis of metagenomes and viromes obtained for three surface water sites showed that the structure of the microbial communities was distinct in comparison to global surveys such as the Tara Ocean, though their composition converges with that of cosmopolitan marine microbes belonging to Proteobacteria, Bacteroidetes, and Actinobacteria. Similarly, viral communities were also divergent in structure and composition but matched known viral members from North America and the southern oceans. Microbial communities were functionally enriched in ARGs dominated by beta-lactams and tetracyclines, bacitracin, and the group macrolide-lincosamide-streptogramin (MLS) but were not different from other communities from the South Atlantic, South Pacific, and Southern Oceans. Similarly, viral communities were characterized by exhibiting protein clusters similar to those described globally (Tara Oceans Virome); however, Comau Fjord viromes displayed up to 50% uniqueness in their protein content. Altogether, our results indicate that microbial and viral communities from the Comau Fjord are a reservoir of untapped diversity and that, given the increasing anthropogenic impacts in the region, they warrant further study, specifically regarding resilience and resistance against antimicrobials and hydrocarbons.
Biotechnological and Oenological Potential of Advanced Genetic Lines of Grapevine Resistant to Powdery Mildew (Erysiphe necator)
(2025) Ormeño Vásquez, Phillip; Sosa Zuniga, Viviana; Gil Cortiella, Mariona; Morales Poblete, René Eduardo; Vallejos, Carolina; Medina, Consuelo; Meneses Araya, Claudio Antonio; Arce Johnson, Patricio
The development of grapevine varieties combining powdery mildew (Erysiphe necator) resistance with acceptable wine quality represents an important goal for sustainable viticulture. This study evaluated the oenological potential of five advanced breeding lines carrying Run1 or Run1Ren1 resistance loci, developed through marker-assisted selection to achieve 99.2–99.6% Vitis vinifera genome content. Genotypes were assessed under Chilean conditions during the 2024–2025 seasons, analyzing disease resistance, berry characteristics, and wine chemical parameters. All resistant genotypes exhibited complete powdery mildew resistance (OIV scores 9) without fungicide applications. Wine analyses showed pH 3.4–3.9, titratable acidity 3.7–7.8 g/L, and total phenolics 229.2–1356.1 mg GAE/L, values within ranges reported in the literature for commercial wines. Two genotypes evaluated across both seasons showed different patterns of year-to-year variation, with AJ-T2 showing 4.7% variation in anthocyanin content, while AJ-T6 exhibited greater variation in phenolic parameters. HPLC analysis revealed anthocyanin profiles dominated by malvidin-3-glucoside without diglucoside forms, consistent with V. vinifera patterns. These preliminary results from single-plant evaluations suggest that marker-assisted breeding may contribute to developing disease-resistant varieties with wine chemical parameters within commercial ranges, though multi-plant trials with appropriate controls are essential for validation.
Characterization of Bunch Compactness in a Diverse Collection of Vitis vinifera L. Genotypes Enriched in Table Grape Cultivars Reveals New Candidate Genes Associated with Berry Number
(MDPI, 2025) Meneses, Marco; Muñoz Espinoza, Claudia; Reyes Impellizzeri, Sofía; Salazar, Erika; Meneses Araya, Claudio Antonio; Herzog, Katja; Hinrichsen, Patricio
Bunch compactness (BC) is a complex, multi-trait characteristic that has been studied mostly in the context of wine grapes, with table grapes being scarcely considered. As these groups have marked phenotypic and genetic differences, including BC, the study of this trait is reported here using a genetically diverse collection of 116 Vitis vinifera L. cultivars and lines enriched for table grapes over two seasons. For this, 3D scanning-based morphological data were combined with ground measurements of 14 BC-related traits, observing high correlations among both approaches (R-2 > 0.90-0.97). The multivariate analysis suggests that the attributes 'berries per bunch', 'berry weight and width', and 'bunch weight and length' could be considered as the main descriptors for BC, optimizing evaluation times. Then, GWASs based on a set of 70,335 SNPs revealed that GBS analysis in this same population enabled the detection of several SNPs associated with different sub-traits, with a locus for 'berries per bunch' in chromosome (chr) 18 being the most prominent. Enrichment analysis of significant and frequent SNPs found simultaneously in several traits and seasons revealed the over-representation of discrete functions such as alpha-linolenic acid metabolism and glycan degradation. In summary, the utility of 3D automated phenotyping was validated for table grape backgrounds, and new SNPs and candidate genes associated with the BC trait were detected. The latter could eventually become a selection tool for grapevine breeding programs.
Cistanthe longiscapa exhibits ecophysiological and molecular adaptations to the arid environments of the Atacama Desert
(OXFORD UNIV PRESS INC, 2025) Ossa, Paulina; Moreno, Adrian A.; Orellana, Daniela; Toro, Monica; Carrasco Valenzuela, Tomas; Riveros, Anibal; Meneses Araya, Claudio Antonio; Nilo Poyanco, Ricardo; Orellana, Ariel
Understanding how plants survive extreme conditions is essential to breeding resilient crops. Cistanthe longiscapa, which flourishes in the Atacama Desert, provides a rare glimpse into plant resilience. To uncover the genetic basis of its stress tolerance, we investigated the ecophysiological and transcriptomic responses of C. longiscapa from 3 sites with low but different precipitation levels. Ecophysiological analyses were performed on samples collected in the field at dusk and dawn, which are crucial stages in crassulacean acid metabolism (CAM), a water-efficient type of photosynthesis. Additional transcriptomic analysis allowed us to evaluate CAM intensity in C. longiscapa and identify changes in the molecular signature of these plants. Our results show that C. longiscapa displays considerable ecophysiological trait response variation across the 3 sites, including variations in markers such as nocturnal acid accumulation, isotopic carbon ratio, and succulence, among others. Analysis of gene expression patterns revealed differences among plants exhibiting varying intensities of CAM photosynthesis and identified key molecular signatures associated with their ecological strategies. Additionally, genes related to stress responses, plastid activities, and circadian rhythm show contrasting expression levels between strong and weak CAM plants, and this expression profile is shared with other CAM plants under stress. Our findings demonstrate that C. longiscapa is a valuable resource for identifying genes involved in the transition between different CAM intensities. This may lead to the discovery of genes that enhance plant tolerance to stressful environments., Cistanthe longiscapa exhibits weak or strong CAM photosynthesis under varying aridity levels in the Atacama Desert, which is associated with contrasting gene expression patterns during dawn and dusk.
Decoding the Hayward kiwi (Actinidia deliciosa var Hayward) genome: transcriptomic responses to drought and salinity and AdhSAP4’s role in salinity stress responses
(2025) Parra, Samuel; Núñez-Lillo, Gerardo; Tapia-Reyes, Patricio; Carrasco-Lozano, Emerson Clovis; Porcile, Vincenzo; Gonzalez-Calquin, Christian; Amaza, Leticia; Quiroz, Luis Felipe; Meneses Araya, Claudio Antonio; Handford, Michael; Norambuena, Lorena; Martínez, Juan Pablo; Stange, Claudia
Abiotic stresses such as drought and salinity pose major limitations to crop productivity, particularly in sensitive species like the Hayward kiwi (Actinidia deliciosa var. Hayward). Stress-associated proteins (SAPs), defined by conserved A20/AN1 zinc finger domains, are emerging as key modulators of plant stress responses. Despite their relevance in model plants, their functional roles in kiwi remain unexplored. In this study we assembled a high-quality haploid reference genome for Hayward kiwi, annotating 42,797 protein-coding genes. RNA-Seq profiling of in vitro leaves exposed to drought (20% PEG-6000) and salinity (200 mM NaCl) at 6 and 24 hours identified differentially expressed genes (DEGs). The differential gene expression kinetics between drought and salinity suggest distinct adaptation mechanisms. Fourteen SAP genes were identified, with AdhSAP4 showing salt-induced expression and homology to rice OsSAP7. Nuclear localization of AdhSAP4-GFP was confirmed, and transgenic tobacco lines overexpressing AdhSAP4 exhibited heightened salt sensitivity, reduced growth, and chlorophyll loss. This study establishes a genomic and transcriptomic framework for kiwi stress biology and confirms AdhSAP4 as a negative regulator of salinity tolerance. The evolutionary conservation of SAP function highlights their potential as biotechnological targets for enhancing stress resilience in perennial crops like kiwi.
Enhanced auxin signaling promotes root-hair growth at moderately low temperature in Arabidopsis thaliana
(Cell Press, 2025) Berdion Gabarain, Victoria; Nuñez Lillo, Gerardo; Pencik, Ales; Carignani Sardoy, Mariana; Ibeas, Miguel Angel; Salinas Grenet, Hernán; Martínez Pacheco, Javier; López, Leonel; Rossi, Andrés Hugo; Miglietta, Esteban A.; Guidobono, Juan Santiago; Zhongtao, Jia; Novak, Ondrej; Hettwer Giehl, Ricardo Fabiano; Wiren, Nicolaus von; Meneses Araya, Claudio Antonio; Estévez, José Manuel
Root hairs (RHs) are mixed tip- and non-tip-growing protrusions derived from root epidermal cells that play essential roles in nutrient and water uptake, root anchorage, and interactions with soil microorganisms. Nutrient availability and temperature are critical and interconnected factors for sustained plant growth, but the molecular mechanisms that underlie their perception and downstream signaling pathways remain unclear. Here, we show that moderately low temperature (10°C) induces a strong RH elongation response mediated by several molecular components of the auxin pathway. Specifically, auxin biosynthesis mediated by TAA1/YUCCAs, auxin transport via PIN2, PIN4, and AUX1, and auxin signaling regulated by TIR1/AFB2 in conjunction with specific ARFs (ARF6/ARF8 and ARF7, but not ARF19) contribute to the RH response under moderately low temperature. These findings establish the auxin biosynthesis and signaling pathway as a central regulatory process driving RH growth under moderate low-temperature conditions in roots. Our work underscores the importance of moderately low temperature as a stimulus that interacts with complex nutritional signaling originating from the growth medium and the plant nutritional status; this process has the potential to be fine-tuned for future biotechnological applications to enhance nutrient uptake.
Fruit sugar hub: gene regulatory network associated with soluble solids content (SSC) in Prunus persica
(2024) Núñez Lillo, Gerardo; Lillo Carmona, Victoria; Pérez Donoso, Alonso Gastón; Pedreschi, Romina; Campos Vargas, Reinaldo; Meneses Araya, Claudio Antonio
Chilean peach growers have achieved worldwide recognition for their high-quality fruit products. Among the main factors influencing peach fruit quality, sweetness is pivotal for maintaining the market's competitiveness. Numerous studies have been conducted in different peach-segregating populations to unravel SSC regulation. However, different cultivars may also have distinct genetic conformation, and other factors, such as environmental conditions, can significantly impact SSC. Using a transcriptomic approach with a gene co-expression network analysis, we aimed to identify the regulatory mechanism that controls the sugar accumulation process in an 'O × N' peach population. This population was previously studied through genomic analysis, associating LG5 with the genetic control of the SSC trait. The results obtained in this study allowed us to identify 91 differentially expressed genes located on chromosome 5 of the peach genome as putative new regulators of sugar accumulation in peach, together with a regulatory network that involves genes directly associated with sugar transport (PpSWEET15), cellulose biosynthesis (PpCSLG2), flavonoid biosynthesis (PpPAL1), pectin modifications (PpPG, PpPL and PpPMEi), expansins (PpEXPA1 and PpEXPA8) and several transcription factors (PpC3H67, PpHB7, PpRVE1 and PpCBF4) involved with the SSC phenotype. These results contribute to a better understanding of the genetic control of the SSC trait for future breeding programs in peaches.
Integration of lipidomics and transcriptomics provides new insights into lipid metabolism in response to water deficit in Prunus spp. rootstock leaves
(Elsevier B.V., 2025) Olmedo, Patricio; Nunez Lillo, Gerardo; Toro, Guillermo; Opazo, Ismael; Salvatierra, Ariel; Meneses Araya, Claudio Antonio; Pedreschi, Romina; Pimentel, Paula
The mechanisms underlying the role of lipids in the response to water deficit in Prunus species have not yet been elucidated. To investigate these, a drought-tolerant rootstock (R40) and a drought-sensitive rootstock (R20) were exposed to well-watered (WW) and water deficit (WD) conditions. We combined physiological, lipidomics, and transcriptomics analyses to elucidate lipid dynamics in rootstock leaves and roots when coping drought. Data showed that R40 genotype possessed a higher stomatal conductance and photosynthetic rate under WD conditions. Lipidomic profiling indicated that most of differences were found in leaves between both genotypes. Under WD conditions, R40 genotype showed a higher number of lipids accumulated, such as ceramides, unsaturated fatty acids, and triacylglycerols. Also, when comparing WW and WD conditions, we observed that drought induced major changes in the R20 genotype. Interestingly, WD reduced the number of accumulated compounds, suggesting a lipid remodeling associated with degradation. Transcriptomic analysis of lipid-related genes showed that the R20 genotype were more responsive to WD, decreasing the expression of these transcripts. A decrease in fatty acid biosynthesis and desaturation was induced in the R20 genotype under WD, while the R40 genotype showed an increased expression of genes associated mainly with biosynthesis of fatty acids and triacylglycerol.
Molecular and Genomic Characterization of the Pseudomonas syringae Phylogroup 4: An Emerging Pathogen of Arabidopsis thaliana and Nicotiana benthamiana
(MDPI, 2022) Zavala, Diego; Fuenzalida Valdivia, Isabel Cristina; Gangas, Maria Victoria; Margutti, Micaela Peppino; Bartoli, Claudia; Roux, Fabrice; Meneses Araya, Claudio Antonio; Herrera Vásquez, Ariel Esteban; Blanco Herrera, María Francisca
Environmental fluctuations such as increased temperature, water availability, and air CO2 concentration triggered by climate change influence plant disease dynamics by affecting hosts, pathogens, and their interactions. Here, we describe a newly discovered Pseudomonas syringae strain found in a natural population of Arabidopsis thaliana collected from the southwest of France. This strain, called Psy RAYR-BL, is highly virulent on natural Arabidopsis accessions, Arabidopsis model accession Columbia 0, and tobacco plants. Despite the severe disease phenotype caused by the Psy RAYR-BL strain, we identified a reduced repertoire of putative Type III virulence effectors by genomic sequencing compared to P. syringae pv tomato (Pst) DC3000. Furthermore, hopBJ1(Psy) is found exclusively on the Psy RAYR-BL genome but not in the Pst DC3000 genome. The plant expression of HopBJ1(Psy) induces ROS accumulation and cell death. In addition, HopBJ1(Psy) participates as a virulence factor in this plant-pathogen interaction, likely explaining the severity of the disease symptoms. This research describes the characterization of a newly discovered plant pathogen strain and possible virulence mechanisms underlying the infection process shaped by natural and changing environmental conditions.
Ontogenetically distinct neutrophils differ in function and transcriptional profile in zebrafish
(Nature Portfolio, 2023) Garcia-Lopez, Juan P.; Grimaldi, Alexandre; Chen, Zelin; Meneses Araya, Claudio Antonio; Bravo-Tello, Karina; Bresciani, Erica; Banderas, Alvaro; Burgess, Shawn M.; Hernandez, Pedro P.; Feijoo, Carmen G.
Neutrophil ontogeny in zebrafish may be a continuum or consist of distinct lineages. Here the authors characterise neutrophils derived from rostral blood island and caudal haematopoietic tissue lineages and show differential gene expression and function in steady state and during wound healing., The current view of hematopoiesis considers leukocytes on a continuum with distinct developmental origins, and which exert non-overlapping functions. However, there is less known about the function and phenotype of ontogenetically distinct neutrophil populations. In this work, using a photoconvertible transgenic zebrafish line; Tg(mpx:Dendra2), we selectively label rostral blood island-derived and caudal hematopoietic tissue-derived neutrophils in vivo during steady state or upon injury. By comparing the migratory properties and single-cell expression profiles of both neutrophil populations at steady state we show that rostral neutrophils show higher csf3b expression and migration capacity than caudal neutrophils. Upon injury, both populations share a core transcriptional profile as well as subset-specific transcriptional signatures. Accordingly, both rostral and caudal neutrophils are recruited to the wound independently of their distance to the injury. While rostral neutrophils respond uniformly, caudal neutrophils respond heterogeneously. Collectively, our results reveal that co-existing neutrophils populations with ontogenically distinct origin display functional differences.
Photosynthetic and Genetic Adaptations Underpinning the Resilience of Cistanthe longiscapa in the Atacama Desert
(2024) Sandoval-Ibáñez, O.; Tapia-Reyes, P.; Riveros, Anibal; Yusta, R.; Chang, S.; Ossa, P.; Nilo-Poyanco, R.; Moreno, A.A.; Miquel, A.; Almeida, A.M.; Zurita-Silva, A.; Orellana, D.; Baeza, C.; Blanco-Herrera, F.; Genova, A.D.; Allende, M.L.; González, M.; Maass, A.; Gutierrez Alliende, Rodrigo Hernan; Meneses Araya, Claudio Antonio
The Atacama Desert is one of the most hostile environments for life. However, the plant species Cistanthe longiscapa (C. longiscapa) completes its life cycle in the Atacama Desert after sporadic rainfall. Physiological analyses under controlled environmental conditions revealed superior photosynthetic performance, better light acclimation mechanisms, and larger accumulation of photosystem II in C. longiscapa compared to its mesophilic sister species. C. longiscapa shows evolutionary expansions in gene families related to DNA repair, photosynthesis, and protein homeostasis. In addition, we observed substantial gene duplication and polymorphic variations between coastal and inland populations in the Atacama Desert. Finally, our assembled mitochondrial genome provides genetic information for all DNA-containing compartments of C. longiscapa. Diurnal oscillations of malic acid and time-resolved transcriptome analyses of plants harvested in the Atacama Desert indicate that C. longiscapa engages in CAM metabolism. We observed significant differences in transcripts encoding plastid-localized proteins, including those involved in carbon metabolism, light harvesting, and photoprotection, highlighting the critical role of chloroplasts in the adaptation of C. longiscapa to the Atacama Desert. Our study provides physiological and genetic evidence for the adaptations of C. longiscapa and advances our understanding of how plants can cope with extreme environmental conditions.
Sup4h5-L19 activation tagging line partially restores root hair growth in p4h5 mutant by introducing small transcriptomic changes in Arabidopsis thaliana
(2024) Urzúa Lehuedé, Tomás; Núñez Lillo, Gerardo; Salgado Salter, Juan; Achá, Romina; Ibeas, Miguel Anguel; Meneses Araya, Claudio Antonio; Estévez, José M.
An specific group of 2-oxoglutarate (2OG) dioxygenases named as Prolyl 4-Hydroxylases (P4H) produce trans-4-hydroxyproline (Hyp/O) from peptidyl-proline, catalyzing proline hydroxylation of cell wall glycoproteins EXT, AGPs, and HRGPs in plant cells, a crucial modification for O-glycosylation. Out of the Arabidopsis thaliana 13 P4Hs, P4H5 regulate root hair cell elongation and T-DNA insertional p4h5 mutant has arrested cell elongation and shortened root hairs. P4H5 selectively hydroxylates EXT proline units indicating that EXT proline hydroxylation as an essential modification for root hair growth. In this work, we isolate an activation-tagging line called Sup4h5-L19/p4h5 (p4h5-L19) that partially suppressed root hair phenotype in the p4h5 mutant background. The T-DNA insertion site was mapped by Thermal Asymmetric Interlaced PCR (TAIL-PCR) followed by PCR product sequencing and the T-DNA is inserted at the beginning of the sixth exon of the AT3G17750 gene, an uncharacterized cytosolic kinase. By analyzing expression changes and mutants analysis in this loci, no clear direct effect was detected. By RNA-seq analysis, it become clear that p4h5-L19 may largely reverse the genetic alterations caused by the p4h5 mutant in Wt Col-0, particularly at 10°C where there is an increase in root hair growth, with a total of 14 genes that have been activated and 83 genes that have been suppressed due to the enhancer of the activation tagging L19 in p4h5 L19 compared to p4h5. Among these genes, 3 of them, Tonoplast Intrinsic Proteins (TIPs), were identified to be root hair specific (TIP1;1, TIP2;2, and TIP2;3) and the corresponding mutants for two of them (TIP1;1 and TIP2;3) showed reduced root hair growth response at low temperature. This study unmasked new components of the root hair growth response at low temperature that works independently of the O-glycosyated EXTs in the cell walls.
The Negative Regulators of the Basal Defence WRKY7, WRKY11 and WRKY17 Modulate the Jasmonic Acid Pathway and an Alternative Splicing Regulatory Network in Response to Pseudomonas syringae in Arabidopsis thaliana
(2024) Fuenzalida Valdivia, Isabel Cristina; Herrera Vásquez, Ariel Esteban; Gangas, Maria Victoria; Saez-Vasquez, Julio; Alvarez, José Miguel; Meneses Araya, Claudio Antonio; Blanco Herrera, María Francisca
In Arabidopsis thaliana, the transcription factors WRKY7, WRKY11 and WRKY17 act as negative defence regulators against Pseudomonas syringae pv. tomato (Pst) DC3000. However, their coordinated regulation of gene expression has yet to be fully explored. In this study, we conducted a transcriptomic analysis on the triple mutant wrky7/11/17 in response to Pst DC3000 at 0, 3 and 24h post-inoculation (hpi). Our results suggest that at early infection stages (0 and 3 hpi), WRKY7, WRKY11 and WRKY17 significantly repress a group of genes involved in signal perception and transduction, including receptor-like kinases. Furthermore, at later stages of interaction (24 hpi), these transcription factors induce genes related to the biosynthesis and signalling of the jasmonic acid (JA) pathway. Further infection experiments with Pst DC3000 in plants treated with methyl jasmonate (a JA analogue) and infections with Botrytis cinerea, a pathogen against which JA-mediated responses are crucial for effective defence, support this proposal. Moreover, we analysed the role of WRKY7, WRKY11 and WRKY17 in alternative splicing regulation. A comparison between differentially expressed (DEG) and spliced (DAS) genes revealed that over 80% of DAS events do not occur in conjunction with overall changes in gene expression. Alternative splicing events were found in genes with functions in splicing and the JA pathway, such as ALY4, PRP40A, JAZ3 and JAZ10. These results suggest that WRKY7, WRKY11 and WRKY17 can also participate in this layer of gene expression regulation to modulate immunity negatively
Transcriptomic reprogramming in a susceptible Phaseolus vulgaris L. variety during Pseudomonas syringae attack: The key role of homogalacturonan methylation
(2022) De la Rubia, Alfonso G.; Largo-Gosens, Asier; Yusta, Ricardo; Sepúlveda, Pablo; Riveros Valdevenito, Anibal Jose; Luz Centeno, María Luz; Sanhueza, Dayan; Meneses Araya, Claudio Antonio; Saez-Aguayo, Susana; García-Angulo, Penélope
The susceptibility of common bean varieties to Pseudomonas pv. syringae phaseolicola (Pph) has been well-documented. However, the molecular mechanism that drives this susceptibility has not been clarified yet. In an attempt to understand this process, 15-day-old common bean plants, variety riñón, were infected with Pph to analyze the transcriptomic changes during the first steps of the infection (at 2 and 9 h). RNA-seq analysis showed an upregulation of defense- and signaling-related genes at 2h, most of them being downregulated at 9h, suggesting that Pph would inhibit the transcriptomic reprogramming of the plant. This trend was also observed in the modulation of 101 cell wall (CW) related genes, suggesting that Pph could produce/induce changes in the CW. However, the changes in CW composition at early stages of Pph infection were related to homogalacturonan (HG) methylation and the formation of HG egg boxes. From all HG-related genes modulated by the infection, a common bean pectin methylesterase inhibitor 3 (PvPMEI3) gene – closely related to AtPMEI3 — was detected. In addition, PMEI3 protein was located in the apoplast and its PME inhibitory activity was demonstrated. Therefore, PvPMEI3 seems to be a good candidate to play a key role in Pph infection. This premise was supported by the analysis of Arabidopsis pmei3 mutant, which showed susceptibility to Pph, in contrast to resistant Col-0 control plants. All these changes could be an attempt to reinforce the CW structure and thus, hinder the attack of the bacterium. However, these transcriptional and CW-remodeling processes are neither maintained during the necessary time, nor are deep enough to block the action of the pathogen, facilitating the well known susceptibility of riñón variety to Pph.
Two antagonistic gene regulatory networks drive Arabidopsis root hair growth at low temperature linked to a low-nutrient environment
(WILEY, 2025) Urzúa Lehuede, Tomás; Berdion Gabarain, Victoria; Ibeas, Miguel Angel; Salinas Grenet, Hernán; Achá Escobar, Romina; Moyano, Tomás C.; Ferrero, Lucía; Núñez Lillo, Gerardo; Pérez Díaz, Jorge; Perotti, María Florencia; Natali Miguel, Virginia; Spies, Fiorella Paola; Rosas, Miguel A.; Kawamura, Ayako; Rodríguez García, Diana R.; Kim, Ah-Ram; Nolan, Trevor; Moreno, Adrian A.; Sugimoto, Keiko; Perrimon, Norbert; Sanguinet, Karen A.; Meneses Araya, Claudio Antonio; Chan, Raquel L.; Ariel, Federico; Alvárez, José M.; Estévez, José M.
Root hair (RH) cells can elongate to several hundred times their initial size, and are an ideal model system for investigating cell size control. Their development is influenced by both endogenous and external signals, which are combined to form an integrative response. Surprisingly, a low-temperature condition of 10 degrees C causes increased RH growth in Arabidopsis and in several monocots, even when the development of the rest of the plant is halted. Previously, we demonstrated a strong correlation between RH growth response and a significant decrease in nutrient availability in the growth medium under low-temperature conditions. However, the molecular basis responsible for receiving and transmitting signals related to the availability of nutrients in the soil, and their relation to plant development, remain largely unknown. We have discovered two antagonic gene regulatory networks (GRNs) controlling RH early transcriptome responses to low temperature. One GNR enhances RH growth and it is commanded by the transcription factors (TFs) ROOT HAIR DEFECTIVE 6 (RHD6), HAIR DEFECTIVE 6-LIKE 2 and 4 (RSL2-RSL4) and a member of the homeodomain leucine zipper (HD-Zip I) group I 16 (AtHB16). On the other hand, a second GRN was identified as a negative regulator of RH growth at low temperature and it is composed by the trihelix TF GT2-LIKE1 (GTL1) and the associated DF1, a previously unidentified MYB-like TF (AT2G01060) and several members of HD-Zip I group (AtHB3, AtHB13, AtHB20, AtHB23). Functional analysis of both GRNs highlights a complex regulation of RH growth response to low temperature, and more importantly, these discoveries enhance our comprehension of how plants synchronize RH growth in response to variations in temperature at the cellular level.

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