Aug 2026· Nature Plants· Vol 12, pp. 1543 - 1560· 0 citations· 97 references
Medicine
TL;DR
The findings uncover a pathway that regulates RH growth as part of a broader, microorganism-dependent root system architecture plasticity under low-water conditions and highlight the potential of uncovering plant–microorganism mechanisms to strengthen crop resilience in a changing climate.
Abstract
Root hairs (RHs) are cellular outgrowths of plant root epidermal cells that are important for water uptake, nutrient acquisition and rhizosphere dynamics. Key genes controlling RH development have been identified, but the regulatory mechanisms of RH growth during drought stress remain largely elusive. Here we show that the bacterial root endophyte Flavobacterium sp. 98 (Flavo98) modulates root system architecture with a pronounced promotion of RH formation and cell elongation that is maintained under low-water conditions. We also show that Flavo98 improves plant performance under drought in diverse plant species, including Arabidopsis and wheat, and mitigates drought-associated seed yield loss. Using cellular, molecular and genetic analyses in Arabidopsis, we identified root stele-expressed ERF transcription factors, ERF115 and ERF114, as key mediators of Flavo98-induced RH development and plant drought responses. We show that both ERFs operate, in part, by inducing the expression of the small signalling peptide C-TERMINALLY ENCODED PEPTIDE 5 (CEP5). In addition, we present evidence for enhanced ethylene biosynthesis and signalling in Flavo98-induced ERF115 and ERF114 expression, revealing a new pathway that integrates ethylene signalling into RH regulation under drought. Together, our findings uncover a pathway that regulates RH growth as part of a broader, microorganism-dependent root system architecture plasticity under low-water conditions. This study highlights the potential of uncovering plant–microorganism mechanisms to strengthen crop resilience in a changing climate. Flavobacterium sp. 98 promotes root hair development and enhances plant drought tolerance via a novel signalling pathway, highlighting the role of plant–microorganism interactions for improving crop resilience under water limitation.
Salinity is a major constraint to crop productivity. Beneficial plant–fungus interactions represent a promising strategy to enhance stress resilience. Here, we investigated fungal endophytes isolated from the roots of Oryza sativa cultivated in saline-prone marshlands of the Guadalquivir River, Spain. From a collection of 38 isolates, five salt-tolerant strains exhibiting plant growth-promoting activity were identified, including a previously uncharacterized Reticulascus sp. strain S5. Co-cultivation assays with the non-native host plant Arabidopsis thaliana demonstrated that S5 increased the root and shoot biomass under salt stress. To elucidate the underlying molecular mechanisms, a comprehensive RNA-Seq analysis of the roots and shoots under control and saline conditions was performed. Fungal colonization induced pronounced transcriptomic changes, particularly in the shoots, including rewiring of the auxin- and abscisic acid-related pathways and the induction of genes associated with cell wall remodeling. Concurrently, defense-related processes, including glucosinolate biosynthesis and ethylene signaling, were broadly repressed, suggesting attenuated stress perception in colonized plants. In the roots, S5 inoculation suppressed the expression of genes involved in root hair development and cell wall organization, indicating a fungus-driven reconfiguration of root development. Moreover, comparative analysis with Fusarium sp. K-23, a fungus that has previously been demonstrated to promote plant growth under salinity stress, revealed distinct root-associated mechanisms but convergence on a shared regulatory module in shoots involving ABA-responsive transcription factors and osmotic stress regulators. Collectively, our findings demonstrate that Reticulascus sp. S5 enhances plant salt stress tolerance through the coordinated transcriptional reprogramming of growth, hormone signaling, and stress responses, highlighting a possible potential of habitat-adapted endophytes for sustainable crop improvement.
Silvia Martínez-Fenoll, Adrián González Ortega-Villaizán, E. Rodríguez-Dobreva et al.· International Journal of Mol...· 0 citations
Phosphorus (P) is an essential macronutrient for plant growth and development. Root hairs enhance P acquisition as inorganic phosphate (Pi) from soil by expanding the root surface area, and their elongation is a key adaptive response to low Pi availability. However, the transcriptional regulators that couple Pi starvation signaling to root hair elongation remain largely unknown. Here, we demonstrate that PHOSPHATE STARVATION RESPONSE1 (PHR1), the central transcription factor of the Pi starvation response, positively regulates Pi deficiency-induced root hair elongation in Arabidopsis. RNA-seq analysis of root tips identified ROOT HAIR DEFECTIVE 6-LIKE 2 (RSL2), a bHLH transcription factor governing root hair elongation, as a prominent PHR1-regulated target. We show that PHR1 binds to the promoter of RSL2 to activate its expression, and genetic analysis confirms that RSL2 acts downstream of PHR1. Further RNA-seq analysis revealed that RSL2 regulates cell wall remodeling genes, among which XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE 26 (XTH26) was identified as a key target. RSL2 binds to the promoter of XTH26 to upregulate its transcription, and XTH26 overexpression partially rescues the reduced root hair length of both phr1 and rsl2. Collectively, our findings delineate a PHR1-RSL2 transcriptional module that orchestrates root hair elongation under Pi deficiency, thereby contributing to enhanced Pi acquisition.
Xinyu Yang, Yi Ding, Yajie Wang et al.· The Plant Journal· 0 citations
BACKGROUND
Seedborne endophytes may facilitate plant establishment by modifying host responses to environmental stress, but the mechanisms underlying these effects remain poorly understood. This may be particularly important for invasive plants, whose establishment in novel habitats often depends on tolerance to abiotic stress.
RESULTS
Here, we examined whether the seed endophytic bacterium Erwinia tasmaniensis YJ6 induces priming-like drought-associated gene expression in the invasive plant Lactuca serriola. We compared the growth and root transcriptomes of uninfected and YJ6-infected plants grown under benign and drought conditions. YJ6 infection mitigated drought-induced reductions in shoot dry weight, root dry weight, and relative leaf growth, whereas these traits decreased in uninfected plants. Under benign water conditions, YJ6 infection induced 1,114 differentially expressed genes, including 317 genes that overlapped with drought-responsive genes in uninfected plants. Functional enrichment analyses showed that bacterial infection under benign conditions and drought exposure in uninfected plants affected several common pathways, including plant hormone signal transduction, phenylpropanoid biosynthesis, and nitrogen metabolism. YJ6 infection also affected genes associated with ABA-related signaling, gibberellin biosynthesis, and soluble sugar metabolism.
CONCLUSION
These results are consistent with the hypothesis that YJ6 infection may establish a priming-like transcriptomic state before drought exposure. This suggests a possible transcriptomic basis for seedborne microbe-mediated stress tolerance in invasive plants, although priming remains to be tested directly.
Se-In Jeong, Tae-Min Kim, Byung-Jun Choi et al.· BMC Plant Biology· 0 citations
Water scarcity impacts soybean cultivation and productivity globally. The ability of plants to withstand drought stress involves complex molecular and physiological mechanisms that facilitate the restoration and maintenance of cellular homeostasis. This study identified genes associated with carbohydrate metabolism and GABA shunt pathway that respond to water deficit in two soybean varieties. These varieties exhibited contrasting responses to water scarcity, and were subjected to two distinct cropping systems. In the drought-tolerant variety, a strategy for conferring tolerance was observed through the pre-emptive priming of the drought response. By applying multivariate analysis, we identified a pivotal gene, GmBAM-like 1, which responds to water scarcity. GmBAM-like 1 encodes a β-amylase and showed rapid activation and elevated expression levels in root tissues of the tolerant variety, suggesting its potential involvement in the drought tolerance response. Transgenic Arabidopsis plants overexpressing GmBAM-like 1 demonstrated enhanced tolerance to salt and osmotic stress, as evidenced by increased survival and germination rates. Additionally, after drought stress, these plants showed higher transpiration rates, larger leaf area, and greater relative water content upon rehydration. These findings demonstrate the potential of integrating the GmBAM-like 1 gene into plant breeding programs to develop cultivars with improved tolerance to water, salt, and osmotic stresses.
Fábia Guimarães-Dias, Lucas Leal Lima, A. C. Neves-Borges et al.· Genetics and Molecular Biolo...· 0 citations
Drought stress is a primary abiotic constraint limiting potato productivity. While polyphenol oxidase (PPO) is known to participate in stress responses, the specific role of StuPPO9 in drought tolerance remains poorly understood. In this study, we generated StuPPO9-overexpressing (OE) and CRISPR/Cas9-mediated knockout (C4) lines in the potato cultivar ‘Atlantic’. Under sustained drought stress, OE lines exhibited significantly superior growth phenotypes compared to wild-type (WT) and C4 plants, characterized by increased leaf and root relative water content, root number and enhanced photosynthetic efficiency (Pn and Gs). OE plants also maintained lower levels of MDA and ROS through elevated antioxidant enzyme activities. Notably, transcriptomic analysis revealed that StuPPO9 triggers a global reprogramming of metabolic pathways. Key drought-responsive genes associated with phenylpropanoid biosynthesis (e.g., anthocyanin acyltransferase), terpenoid metabolism, and hormone signaling (e.g., HPt protein) were significantly upregulated in OE plants. These findings suggest that StuPPO9 confers drought resilience through a multi-layered network involving optimized carbon allocation, reinforced cell wall integrity, and enhanced ROS scavenging capacity. This study provides a promising genetic target and theoretical foundation for breeding drought-resistant potato varieties.
Ming-Kun Chi, Boyang Liu, Heng-Zhao Yang et al.· Plants· 0 citations
The results suggest that OsCYP51H9 participates in the phytosterol-BR pathway and plays a positive role in rice adaptation to low-nitrogen environments, providing a potential target for molecular breeding.
Zhengli Jiao, Jianyi Li, Weijuan Xu et al.· Plant physiology and biochem...· 0 citations