Oil palm (Elaeis guineensis Jacq.) is a highly productive crop economically significant for food, cosmetics, and biofuels. Abiotic stresses such as low water availability, salt accumulation, and high temperatures severely impact oil palm growth, physiology, and yield by restricting water flux among soil, plants, and the environment. While drought stress’s physiological and biochemical effects on oil palm have been extensively studied, the molecular mechanisms underlying drought stress tolerance remain unclear. Under water deficit conditions, this study investigates two commercial E. guineensis cultivars, IRHO 7001 and IRHO 2501. Water deficit adversely affected the physiology of both cultivars, with IRHO 2501 being more severely impacted. After several days of water deficit, there was a 40% reduction in photosynthetic rate (A) for IRHO 7001 and a 58% decrease in IRHO 2501. Further into the drought conditions, there was a 75% reduction in A for IRHO 7001 and a 91% drop in IRHO 2501. Both cultivars reacted to the drought stress conditions by closing stomata and reducing the transpiration rate. Despite these differences, no significant variations were observed between the cultivars in stomatal conductance, transpiration, or instantaneous leaf-level water use efficiency. This indicates that IRHO 7001 is more tolerant to drought stress than IRHO 2501. A differential gene expression and network analysis was conducted to elucidate the differential responses of the cultivars. The DESeq2 algorithm identified 502 differentially expressed genes (DEGs). The gene coexpression network for IRHO 7001 comprised 274 DEGs and 46 predicted HUB genes, whereas IRHO 2501’s network included 249 DEGs and 3 HUB genes. RT-qPCR validation of 15 DEGs confirmed the RNA-Seq data. The transcriptomic profiles and gene coexpression network analysis revealed a set of DEGs and HUB genes associated with regulatory and transcriptional functions. Notably, the zinc finger protein ZAT11 and linoleate 13S-lipoxygenase 2-1 (LOX2.1) were overexpressed in IRHO 2501 but under-expressed in IRHO 7001. Additionally, phytohormone crosstalk was identified as a central component in the response and adaptation of oil palm to drought stress.

Bud Rot, caused by Phytophthora palmivora, is considered one of the main diseases affecting African oil palm (Elaeis guineensis). In this study, we investigated the in vitro molecular dynamics of the pathogen–host interaction by analyzing gene expression profiles from oil palm genotypes that were either susceptible or resistant to the disease. We observed distinct interactions of P. palmivora with resistant and susceptible oil palms through co-expression network analysis. When interacting with susceptible genotypes, P. palmivora exhibited upregulation of carbohydrate and sulfate transport genes. These genes demonstrated co-expression with apoplastic and cytoplasmic effectors, including cell wall degrading enzymes, elicitins, and RxLR motif effectors. The pathogen manipulated susceptible oil palm materials, exacerbating the response and compromising the phenylpropanoid pathway, ultimately leading to susceptibility. In contrast, resistant materials exhibited control over their response through putative Heat Shock Proteins (HSP) that maintained homeostasis between primary metabolism and biotic defense. Co-expressed genes related to flavonoids, WRKY transcripts, lectin-type receptors, and LRR receptors may play important roles in pathogen control. Overall, the study provides new knowledge of the molecular mechanisms underlying the interaction between E. guineensis and P. palmivora, which can contribute to controlling Bud Rot in oil palms and gives new insights into the interactions of P. palmivora with their hosts.

Lethal wilt (LW), known as “Marchitez Letal” in Colombia, is an endemic disease affecting oil palms (Elaeis guineensis Jacq.) and a leading cause of crop loss. The disease is characterized by the drying of leaflets from the tip to the base, primarily impacting the lower third of the plant and progressively moving upward. This progression leads to physiological disturbances, including necrosis at the tips of immature inflorescence bracts (spines) and the detachment of bunch fruits, ultimately causing wilting. As a phytosanitary measure, infected palms are eradicated to prevent further spread of the disease. The primary goal of this research was to identify the bacteria associated with LW and to validate a molecular detection method. A 16S amplicon-based analysis was employed to identify and compare the microbial diversity in LW-affected palm tissues with those of healthy plants. Among the 16 OTUs corresponding to different bacterial genera found in all LW samples, taxonomic classification and symptomatology suggested that the bacteria closely associated with LW belong to the genus ‘Candidatus Liberibacter’. Further phylogenetic analysis indicated that these bacteria are part of the Rhizobiaceae family, grouping closely with other species of the genus ‘Ca. Liberibacter’. The concentration of the pathogen in different oil palm tissues was determined using droplet digital PCR and quantitative PCR, expressed in copies/μl in the LW samples. This study represents the first report of ‘Ca. Liberibacter’ sp. being associated with lethal wilt in oil palms of the Arecaceae family in Colombia. The findings from this research could contribute significantly to the development of effective management strategies to prevent crop losses. [ ] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

La partenocarpia es el desarrollo de frutos sin semillas en ausencia de fertilización. En la industria de la palma de aceite, el desarrollo de frutos partenocárpicos se considera una alternativa atractiva para aumentar la producción de aceite de palma. Estudios previos han demostrado que la aplicación de auxinas sintéticas en Elaeis guineensis e híbridos interespecíficos O×G (Elaeis oleifera (Kunth) Cortés×Elaeis guineensis Jacq.) induce la partenocarpia. El objetivo de este estudio fue identificar el mecanismo molecular,mediante un enfoque transcriptómico y de biología de sistemas, para explicar cómo la aplicación de ácido naftalenacético (ANA) induce la formación de frutos partenocárpicos en híbridos O×G de palma de aceite. Se estudiaron los cambios en el transcriptoma en tres estadios fenológicos (EF) de las inflorescencias: 1) EF 603,preantesis III,2) EF 607,antesis, y 3) EF 700,flor femenina fertilizada. Cada EF fue tratado con ANA, polen y un control (sin aplicación). El perfil de expresión se analizó en tres momentos distintos: cinco minutos (T0),24 horas (T1) y 48 horas después del tratamiento (T2). Se utilizó el método de secuenciación de ARN con 27 híbridos O×G de palma de aceite,lo que supuso un total de 81 muestras para procesar. La secuenciación de ARN identificó alrededor de 445.920 genes. Numerosos genes expresados diferencialmente (GED) estuvieron involucrados en la polinización, la floración, el desarrollo de las semillas,la biosíntesis de hormonas y la transducción de señales. La expresión de las familias de factores de transcripción (FT) más relevantes fue variable y dependió del estadio fenológico y el tiempo posterior al tratamiento.