Auxin-Dependent Activation of RHD6-RSL4 Cascade Promotes Root Hair Growth Under Boron Deficiency in Arabidopsis Primary Root Apices Cristina Bahamonde, Clara de la Osa, Jesús Rexach, M. Begoña Herrera‐Rodríguez, Victoria Berdion Gabarain, et al. Plant Cell and Environment, 2026 Plants rapidly adjust their root system architecture to enhance resource uptake and cope with fluctuating soil environments. One such adaptive response is the development of root hairs (RH), which increase the effective root surface area and thereby improve water and nutrient acquisition. Here, we show that Arabidopsis seedlings respond rapidly to boron (B) deficiency by increasing both RH density and length at the root tip. This response is strongly correlated with enhanced auxin signaling in the root apex, as revealed by the auxin‐responsive reporters IAA2::GUS and DR5rev:GFP. Our findings support the idea that B deficiency leads to auxin accumulation in the root tip, likely mediated by enhanced shoot‐to‐root auxin transport. Furthermore, by using pharmacological and genetic approaches, we provide evidence that enhanced auxin signaling via TIR1/AFBs in the RH zone activates the RHD6‐RSL4 cascade to promote RH elongation under B deficiency. In contrast, the increase in RH density under B‐deficient conditions appears to involve additional auxin‐independent regulatory mechanisms.
Fusarium sp. Strain K-23 Alleviates Salt Stress in Arabidopsis thaliana Through its Root Hair Growth-Promoting Effect Francis C. Onejeme, Adrián González Ortega-Villaizán, Estefanía Rodríguez-Dobreva, Basha Topel Prieto, Manish K. Patel, et al. Journal of Plant Growth Regulation, 2025 Soil salinity is a significant abiotic stress factor that impedes plant growth and crop yield, particularly in arid and semi-arid regions. Recent reports indicate that 8.7% of soils globally and 20–50% of irrigated soils across all continents are affected by salt. This phenomenon jeopardizes the food security of more than 1.5 billion people worldwide. Numerous studies have elucidated the beneficial effects of diverse microbes on plant abiotic stress tolerance. In this study, we report on an observed molecular mechanism involved in the enhanced salt tolerance of Arabidopsis plants co-cultivated with the Fusarium sp. strain K-23. Employing a combination of transcriptomics, phenomics, reverse genetics, and live cell imaging, we elucidated the intricacies of biological processes that influence root growth in the interaction between A. thaliana and the fungus. Moreover, our research corroborated the beneficial effect of the fungus under salt-stress conditions for Arabidopsis and highlighted notable differences compared to previous studies. We utilized an RNA-seq approach to identify biological processes triggered in Arabidopsis roots that interact with K-23, resulting in increased salt tolerance. These experiments necessitated a more comprehensive investigation into the fungal influence on root hair development and elucidated that induced root hair growth was a prerequisite for the enhanced salt stress tolerance conferred by the fungus. Furthermore, we demonstrate that the fungus induces the expression of the NAC transcription factor JUNGBRUNNEN 1 ( JUB1 ). Elevated expression of JUB1 leads to repression of gibberellin biosynthesis, which, in turn, contributes to sustained root hair growth under salt stress conditions, which typically suppresses root hair growth substantially.
Two antagonistic gene regulatory networks drive Arabidopsis root hair growth at low temperature linked to a low-nutrient environment Tomás Urzúa Lehuedé, Victoria Berdion Gabarain, Miguel Angel Ibeas, Hernán Salinas‐Grenet, Romina Achá‐Escobar, et al. New Phytologist, 2025 Summary 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°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.
Filling the gaps on root hair development under salt stress and phosphate starvation using current evidence coupled with a meta-analysis approach Miguel Angel Ibeas, Hernán Salinas-Grenet, Nathan R Johnson, Jorge Pérez-Díaz, Elena A Vidal, et al. Plant Physiology, 2024 Population expansion is a global issue, especially for food production. Meanwhile, global climate change is damaging our soils, making it difficult for crops to thrive and lowering both production and quality. Poor nutrition and salinity stress affect plant growth and development. Although the impact of individual plant stresses has been studied for decades, the real stress scenario is more complex due to the exposure to multiple stresses at the same time. Here we investigate using existing evidence and a meta-analysis approach to determine molecular linkages between 2 contemporaneous abiotic stimuli, phosphate (Pi) deficiency and salinity, on a single plant cell model, the root hairs (RHs), which is the first plant cell exposed to them. Understanding how these 2 stresses work molecularly in RHs may help us build super-adaptable crops and sustainable agriculture in the face of global climate change.
RAPID ALKALINIZATION FACTOR 22 is a key modulator of the root hair growth responses to fungal ethylene emissions in Arabidopsis Rafael Jorge León Morcillo, Jesús Leal-López, Alberto Férez-Gómez, Lidia López-Serrano, Edurne Baroja-Fernández, et al. Plant Physiology, 2024 In Arabidopsis (Arabidopsis thaliana (L.) Heynh), exposure to volatile compounds (VCs) emitted by Penicillium aurantiogriseum promotes root hair (RH) proliferation and hyper-elongation through mechanisms involving ethylene, auxin, and photosynthesis signaling. In addition, this treatment enhances the levels of the small signaling peptide RAPID ALKALINIZATION FACTOR 22 (RALF22). Here, we used genetics to address the role of RALF22 in fungal VC-promoted RH growth and to identify the bioactive fungal VC. We found that RHs of ralf22 and feronia (fer-4) plants impaired in the expression of RALF22 and its receptor FERONIA, respectively, responded weakly to fungal VCs. Unlike in wild-type roots, fungal VC exposure did not enhance RALF22 transcript levels in roots of fer-4 and ethylene- and auxin-insensitive mutants. In ralf22 and fer-4 roots, this treatment did not enhance the levels of ERS2 transcripts encoding one member of the ethylene receptor family and those of some RH-related genes. RHs of ers2-1 and the rsl2rsl4 double mutants impaired in the expression of ERS2 and the ethylene- and auxin-responsive ROOT HAIR DEFECTIVE 6-LIKE 2 and 4 transcription factors, respectively, weakly responded to fungal VCs. Moreover, roots of plants defective in photosynthetic responsiveness to VCs exhibited weak RALF22 expression and RH growth responses to fungal VCs. VCs of ΔefeA strains of P. aurantiogriseum cultures impaired in ethylene synthesis weakly promoted RH proliferation and elongation in exposed plants. We conclude that RALF22 simultaneously functions as a transcriptionally regulated signaling molecule that participates in the ethylene, auxin, and photosynthesis signaling-mediated RH growth response to fungal ethylene emissions and regulation of ethylene perception in RHs.
Current challenges for plant biology research in the Global South Gabriela Auge, Rohan Shawn Sunil, Robert A. Ingle, Puthan Valappil Rahul, Marek Mutwil, et al. New Phytologist, 2024 SummaryIn an attempt to address the large inequities faced by the plant biology communities from the Global South (i.e. countries located around the tropics and the Southern Hemisphere) at international conferences, this Viewpoint is the reflexive thinking arising from the concurrent session titled ‘Arabidopsis and its translational research in the Global South’ organized at the International Conference of Arabidopsis Research 2023 (ICAR 2023) in Chiba, Japan in June 2023. Here, we highlight the main obstacles plant biology communities in the Global South face in terms of knowledge production, as measured by the unequal production and citation of publications, investigating and advancing local plant genomics and biodiversity, combating disparities in gender and diversity, and current initiatives to break isolation of scientists.
Exploring the puzzle of reactive oxygen species acting on root hair cells Leonel E Lopez, Miguel A Ibeas, Gabriela Diaz Dominguez, Jose M Estevez Journal of Experimental Botany, 2024 Reactive oxygen species (ROS) are essential signaling molecules that enable cells to respond rapidly to a range of stimuli. The ability of plants to recognize various stressors, incorporate a variety of environmental inputs, and initiate stress-response networks depends on ROS. Plants develop resilience and defensive systems as a result of these processes. Root hairs are central components of root biology since they increase the surface area of the root, anchor it in the soil, increase its ability to absorb water and nutrients, and foster interactions between microorganisms. In this review, we specifically focused on root hair cells and we highlighted the identification of ROS receptors, important new regulatory hubs that connect ROS production, transport, and signaling in the context of two hormonal pathways (auxin and ethylene) and under low temperature environmental input related to nutrients. As ROS play a crucial role in regulating cell elongation rates, root hairs are rapidly gaining traction as a very valuable single plant cell model for investigating ROS homeostasis and signaling. These promising findings might soon facilitate the development of plants and roots that are more resilient to environmental stressors.
Molecular link between auxin and ROS-mediated polar growth Silvina Mangano, Silvina Paola Denita-Juarez, Hee-Seung Choi, Eliana Marzol, Youra Hwang, et al. Proceedings of the National Academy of Sciences of the United States of America, 2017
Vacuolar and ER-Ca 2+ -ATPases regulate calcium dynamics during pollen tube growth in Arabidopsis thaliana J García Bossi, ML Barberini, M Grenzi, G Tortora, F Santín, A Bassi, ... Plant Physiology, kiag275 , 2026 2026
Auxin‐Dependent Activation of RHD6‐RSL4 Cascade Promotes Root Hair Growth Under Boron Deficiency in Arabidopsis Primary Root Apices C Bahamonde Pereira, C de la Osa, J Rexach, MB Herrera Rodríguez, ... Wiley , 2026 2026
Posttranslational regulation of TOR kinase activity controls resource allocation between plant growth and immunity in Arabidopsis J Li, R Wang, C Li, X Guo, Q Li, Z Wu, S Zeng, F Qi, Y Wang, Z Jia, W Yu, ... Molecular Plant 19 (3), 629-650 , 2026 2026 Citations: 1
Auxin‐Dependent Activation of RHD6‐RSL4 Cascade Promotes Root Hair Growth Under Boron Deficiency in Arabidopsis Primary Root Apices C Bahamonde, C de la Osa, J Rexach, MB Herrera‐Rodríguez, ... Plant, Cell & Environment , 2026 2026
MLOs downstream of FERONIA help to maintain root hair apical growth by tuning Ca 2+ and ROS secondary messengers' oscillations E Michard, JM Estevez New Phytologist 248 (6), 2641-2644 , 2025 2025
Fusarium sp. Strain K-23 Alleviates Salt Stress in Arabidopsis thaliana Through its Root Hair Growth-Promoting Effect FC Onejeme, A González Ortega-Villaizán, E Rodríguez-Dobreva, ... Journal of Plant Growth Regulation 44 (12), 7089-7105 , 2025 2025 Citations: 2
What Large Language Models Know About Plant Molecular Biology M Fernandez Burda, L Ferrero, N Gaggion, C Fonouni-Farde, ... bioRxiv, 2025.08. 31.672925 , 2025 2025 Citations: 1
Enhanced auxin signaling promotes root-hair growth at moderately low temperature in Arabidopsis thaliana VB Gabarain, G Núñez-Lillo, A Pěnčík, MC Sardoy, MA Ibeas, ... Plant Communications 6 (6) , 2025 2025 Citations: 8
Two antagonistic gene regulatory networks drive Arabidopsis root hair growth at low temperature linked to a low‐nutrient environment T Urzúa Lehuedé, V Berdion Gabarain, MA Ibeas, H Salinas‐Grenet, ... New Phytologist 245 (6), 2645-2664 , 2025 2025 Citations: 8
RAPID ALKALINIZATION FACTOR 22 is a key modulator of the root hair growth responses to fungal ethylene emissions in Arabidopsis RJL Morcillo, J Leal-López, A Férez-Gómez, L López-Serrano, ... Plant Physiology 196 (4), 2890-2904 , 2024 2024 Citations: 10
Filling the gaps on root hair development under salt stress and phosphate starvation using current evidence coupled with a meta-analysis approach MA Ibeas, H Salinas-Grenet, NR Johnson, J Pérez-Díaz, EA Vidal, ... Plant Physiology 196 (4), 2140-2149 , 2024 2024 Citations: 9
Current challenges for plant biology research in the Global South G Auge, RS Sunil, RA Ingle, PV Rahul, M Mutwil, JM Estevez New Phytologist 244 (4), 1168-1174 , 2024 2024 Citations: 10
Enhanced auxin signaling hub triggers root hair growth at moderate low temperature in Arabidopsis thaliana VB Gabarain, G Núñez-Lillo, A Pěnčík, MA Ibeas, JM Pacheco, L Lopez, ... bioRxiv, 2024.08. 15.608078 , 2024 2024 Citations: 2
Exploring the puzzle of reactive oxygen species acting on root hair cells LE Lopez, MA Ibeas, G Diaz Dominguez, JM Estevez Journal of Experimental Botany 75 (15), 4589-4598 , 2024 2024 Citations: 12
Arabidopsis pollen prolyl-hydroxylases P4H4/6 are relevant for correct hydroxylation and secretion of LRX11 in pollen tubes AR Sede, DL Wengier, C Borassi, M Ricardi, SC Somoza, R Aguiló, ... Journal of Experimental Botany 75 (14), 4415-4427 , 2024 2024 Citations: 5
New molecular components that regulate the transcriptional hub in root hairs: coupling environmental signals with endogenous hormones to coordinate growth LE Lopez, YS Chuah, F Encina, M Carignani Sardoy, V Berdion Gabarain, ... Journal of Experimental Botany 75 (14), 4171-4179 , 2024 2024 Citations: 12
Su p4h5 -L19 activation tagging line partially restores root hair growth in p4h5 mutant by introducing small transcriptomic changes in Arabidopsis thaliana T Urzúa Lehuedé, G Núñez-Lillo, J Salgado Salter, R Acha, MA Ibeas, ... bioRxiv, 2024.06. 14.599040 , 2024 2024
Auxin signaling gets oxidative to promote root hair growth VB Gabarain, MA Ibeas, H Salinas-Grenet, JM Estevez Molecular Plant 17 (5), 696-698 , 2024 2024 Citations: 2
Unheard voices speak up: the Arabidopsis community and the representation of researchers from the Global South G Auge, JM Estevez Journal of Experimental Botany 75 (8), 2193-2195 , 2024 2024
The exception to the rule? TORC1 triggers growth under low nutrient environments LE Lopez, JM Pacheco, JM Estevez Trends in Plant Science 29 (1), 13-15 , 2024 2024 Citations: 2
MOST CITED SCHOLAR PUBLICATIONS
Discovery of lignin in seaweed reveals convergent evolution of cell-wall architecture PT Martone, JM Estevez, F Lu, K Ruel, MW Denny, C Somerville, J Ralph Current biology 19 (2), 169-175 , 2009 2009 Citations: 643
O-glycosylated cell wall proteins are essential in root hair growth SM Velasquez, MM Ricardi, JG Dorosz, PV Fernandez, AD Nadra, ... Science 332 (6036), 1401-1403 , 2011 2011 Citations: 387
Molecular link between auxin and ROS-mediated polar growth S Mangano, SP Denita-Juarez, HS Choi, E Marzol, Y Hwang, P Ranocha, ... Proceedings of the National Academy of Sciences 114 (20), 5289-5294 , 2017 2017 Citations: 306
Cellulose microfibril crystallinity is reduced by mutating C-terminal transmembrane region residues CESA1A903V and CESA3T942I of cellulose synthase DM Harris, K Corbin, T Wang, R Gutierrez, AL Bertolo, C Petti, ... Proceedings of the National Academy of Sciences 109 (11), 4098-4103 , 2012 2012 Citations: 221
Disruption of Abscisic Acid Signaling Constitutively Activates Arabidopsis Resistance to the Necrotrophic Fungus Plectosphaerella cucumerina A Sánchez-Vallet, G López, B Ramos, M Delgado-Cerezo, MP Riviere, ... Plant physiology 160 (4), 2109-2124 , 2012 2012 Citations: 192
Arabidopsis heterotrimeric G-protein regulates cell wall defense and resistance to necrotrophic fungi M Delgado-Cerezo, C Sánchez-Rodríguez, V Escudero, E Miedes, ... Molecular plant 5 (1), 98-114 , 2012 2012 Citations: 182
The RALF1–FERONIA complex phosphorylates eIF4E1 to promote protein synthesis and polar root hair growth S Zhu, JM Estévez, H Liao, Y Zhu, T Yang, C Li, Y Wang, L Li, X Liu, ... Molecular Plant 13 (5), 698-716 , 2020 2020 Citations: 168
An update on post-translational modifications of hydroxyproline-rich glycoproteins: toward a model highlighting their contribution to plant cell wall architecture M Hijazi, SM Velasquez, E Jamet, JM Estevez, C Albenne Frontiers in plant science 5, 395 , 2014 2014 Citations: 163
Auxin and cellular elongation SM Velasquez, E Barbez, J Kleine-Vehn, JM Estevez Plant physiology 170 (3), 1206-1215 , 2016 2016 Citations: 158
Novel DL-Galactan Hybrids from the Red Seaweed Gymnogongrus Torulosus are Potent Inhibitors of Herpes Simplex Virus and Dengue Virus CA Pujol, JM Estevez, MJ Carlucci, M Ciancia, AS Cerezo, EB Damonte Antiviral Chemistry and Chemotherapy 13 (2), 83-89 , 2002 2002 Citations: 155
Chemical and in situ characterization of macromolecular components of the cell walls from the green seaweed Codium fragile JM Estevez, PV Fernández, L Kasulin, P Dupree, M Ciancia Glycobiology 19 (3), 212-228 , 2009 2009 Citations: 152
ROS regulation of polar growth in plant cells S Mangano, SPD Juárez, JM Estevez Plant physiology 171 (3), 1593-1605 , 2016 2016 Citations: 148
The lncRNA APOLO interacts with the transcription factor WRKY42 to trigger root hair cell expansion in response to cold M Moison, JM Pacheco, L Lucero, C Fonouni-Farde, J Rodríguez-Melo, ... Molecular Plant 14 (6), 937-948 , 2021 2021 Citations: 144
The ERECTA Receptor-Like Kinase Regulates Cell Wall–Mediated Resistance to Pathogens in Arabidopsis thaliana C Sánchez-Rodríguez, JM Estévez, F Llorente, C Hernández-Blanco, ... Molecular plant-microbe interactions 22 (8), 953-963 , 2009 2009 Citations: 140
Polysaccharides from the green seaweeds Codium fragile and C. vermilara with controversial effects on hemostasis M Ciancia, I Quintana, MI Vizcargüénaga, L Kasulin, A de Dios, ... International Journal of Biological Macromolecules 41 (5), 641-649 , 2007 2007 Citations: 134
Genome-wide data (ChIP-seq) enabled identification of cell wall-related and aquaporin genes as targets of tomato ASR1, a drought stress-responsive transcription factor MM Ricardi, RM González, S Zhong, PG Domínguez, T Duffy, ... BMC plant biology 14 (1), 29 , 2014 2014 Citations: 124
Potato snakin-1 gene silencing affects cell division, primary metabolism, and cell wall composition V Nahirñak, NI Almasia, PV Fernandez, HE Hopp, JM Estevez, F Carrari, ... Plant Physiology 158 (1), 252-263 , 2012 2012 Citations: 121
Red and green algal monophyly and extensive gene sharing found in a rich repertoire of red algal genes CX Chan, EC Yang, T Banerjee, HS Yoon, PT Martone, JM Estevez, ... Current Biology 21 (4), 328-333 , 2011 2011 Citations: 121
Arabidopsis pollen extensins LRX are required for cell wall integrity during pollen tube growth AR Sede, C Borassi, DL Wengier, MA Mecchia, JM Estevez, JP Muschietti FEBS letters 592 (2), 233-243 , 2018 2018 Citations: 114
An update on cell surface proteins containing extensin-motifs C Borassi, AR Sede, MA Mecchia, JD Salgado Salter, E Marzol, ... Journal of Experimental Botany 67 (2), 477-487 , 2016 2016 Citations: 111
