Summary Insect oviposition fluid plays a role in the early recognition of plants and the initiation of plant defense responses. However, the characterization of oviposition fluid proteins and their relationship with plant defenses remains poorly understood. The oviposition fluid protein NlOFP1 in the brown planthopper ( Nilaparvata lugens ) is synthesized in the ovarian follicular cells and can be deposited into rice tissue. Functional studies reveal that NlOFP1 helps eggs resist desiccation stress. Furthermore, it can suppress plant defenses. NlOFP1 ‐silencing leads to decreased honeydew secretion, fecundity, and egg hatching rate. Orthologs of NlOFP1 in other planthopper species exhibit highly conserved functions. Transgenic rice overexpressing NlOFP1 showed reduced lignin and salicylic acid, increased cellulose, and downregulated resistance genes, indicating weakened defense responses of plants. This phenotype effectively compensated for the adaptive loss caused by NlOFP1 silencing in the brown planthopper. NlOFP1 interacted with the photosynthetic electron transport chain component OsFeS. This interaction partially impaired the import of OsFeS into the chloroplasts and might lead to a decline in plant resistance. Our study reveals that NlOFP1 acts as an effector against plant defense responses and provides insights into pest reproduction and host defense evasion.
Summary Afforestation regulates soil organic carbon (SOC) sequestration via plant‐ and microbial‐derived carbon (C) inputs, but root‐ and mycelium‐derived C inputs differ in quantity, turnover, and stabilization mechanisms, and these differences may shift as stands develop. However, how root vs mycelium pathways drive SOC dynamics across a dryland afforestation chronosequence remains unclear. Using the ingrowth‐core method along a dryland afforestation chronosequence (young forests, middle‐aged forests, and mature forests), we quantified the contributions of root and mycelium pathways to SOC. The root pathway promoted SOC accumulation via particulate organic C and mineral‐associated organic C inputs, contributing to 77.19–85.05% of the SOC changes. By contrast, the mycelium pathway induced net SOC loss via particulate organic C depletion, contributing to 14.95–22.81% of the SOC changes. SOC concentrations peaked in middle‐aged forests, whereas relative SOC stability peaked in young forests. This study provides the first quantitative assessment of the distinct contributions of root and mycelium pathways to SOC accumulation and stabilization during dryland afforestation, advancing understanding of their roles in regulating SOC dynamics. As climate change intensifies land‐use pressure, management strategies should integrate stage‐specific root and mycelial traits to enhance SOC sequestration in arid forests.
Summary In rice ( Oryza sativa ), the root architecture is heavily shaped by shoot‐borne crown roots that arise from the phytomers at the stem base. Each phytomer typically generates two spatially distinct crown root populations – lower/proximal and upper/distal crown roots – that also emerge temporally, with the proximal roots forming first. The mechanisms that coordinate this temporospatial patterning, however, remain poorly understood. Here, we identify an AP2/ERF gene OsERF27 which is differentially expressed between proximal and distal crown root primordia and is specifically required for the timely development of proximal roots. We further show that OsPLT4 functions downstream of OsERF27 , defining an OsERF27‐OsPLT4 regulatory module that drives the outgrowth and emergence of proximal crown roots. Interestingly, we uncover a requirement for reactive oxygen species (ROS) homeostasis in crown root development: Loss‐of‐function mutants display disturbed ROS accumulation pattern and sensitized root formation to ROS perturbation, indicating that this module promotes root emergence by spatially maintaining optimal redox balance. Together, our findings reveal a multi‐layered regulatory network that integrates genetic elements with positional cues with redox control to pattern distinct crown root populations. Our study highlights how localized developmental programmes scale to shape root system architecture for tuning plant form and function in grasses.
Auxin is a central phytohormone that mediates root development. This study investigated the genetic basis of auxin-mediated primary root growth in Zea mays (maize) seedlings, which is not well-understood in this key cereal crop. To address this knowledge gap, 618 accessions from the Wisconsin Diversity panel were leveraged for a genome wide association study (GWAS) followed by reverse genetics and in silico gene regulatory network reconstruction (GRN). The GWAS identified several candidate genes associated with variation in root growth responses, including RAMOSA2 and multiple members of the AUXIN RESPONSE FACTOR (ARF) gene family. Maize AUXIN RESPONSE FACTOR27 (ZmARF27), an ortholog of Arabidopsis ARF7 and ARF19, was prioritized for functional characterization. A reduction in ZmARF27 levels led to short primary roots, insensitivity to exogenous auxin, and altered transcriptional responses. Reconstruction of an ZmARF27 GRN included known maize classical root development genes, such as ROOTLESS CONCERNING CROWN ROOTS, numerous auxin pathway genes, and genes associated with cell wall biogenesis. Altogether, this study identifies ZmARF27 as a novel genetic driver of auxin-mediated root growth and gene expression in maize.
