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Results for “parasitic lifestyle”

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3 recordsLinked to original sources
PubMed2026

From Sequential Gland Replacement to Recurrent Gland Coordination: A Comparative Framework for Subventral and Dorsal Oesophageal Gland Effectors Across Plant-Parasitic Nematode Lifestyles.

Plant-parasitic nematodes manipulate host tissues through stylet-secreted gene products synthesised principally in two subventral and one dorsal oesophageal gland. Earlier reviews have catalogued effector repertoires, described feeding-site formation, and explained how individual effectors modify host defence, development, and metabolism. However, the temporal coordination of the gland cells themselves has not been comparatively synthesised across parasitic lifestyles. This review therefore advances a gland-centred, lifestyle-dependent framework. In sedentary endoparasites, available evidence supports a pronounced developmental transition: subventral gland products dominate penetration and migration, whereas dorsal gland products become increasingly important during feeding-site initiation and maintenance. Migratory endoparasites repeatedly penetrate, migrate, and feed without establishing permanent feeding cells; their gland activity is consequently predicted to be recurrent and overlapping rather than a one-way replacement. Ectoparasites likewise require behaviour-dependent coordination during repeated probing and external feeding, although direct gland localisation evidence remains limited. We integrate gland origin, secretion chemistry, infection stage, and parasitic behaviour across root-knot, cyst, citrus, false root-knot, lesion, burrowing, and ectoparasitic nematodes. The synthesis distinguishes experimentally demonstrated gland localisation from evidence-weighted inference and formulates testable predictions for comparative gland transcriptomics, spatial expression, and functional silencing. This framework also identifies gland activation, secretion, and stage-critical products as targets for RNA interference, genome editing, resistance breeding, and sustainable nematode management. The principal novelty is therefore not another catalogue of nematode effectors, but a comparative model explaining when and why subventral and dorsal glands exchange, retain, or alternate their functions across contrasting parasitic lifestyles.

dorsal gland↗
PubMed2026

The genome of Thesium ramosoides (Santalales) reveals evolutionary dynamics associated with parasitism and alpine adaptation.

Plant species adapting to complex environments experience contrasting selection pressures that drive the expansion and contraction of different gene families. However, few studies have investigated simultaneous genomic responses to such diverse selective forces. Here, we generate a high-quality genome assembly for the hemiparasitic plant Thesium ramosoides, the first for the largest genus in the Santalales, and explore the genomic basis underlying the evolution of parasitism and alpine adaptation. Unlike many other parasitic plants, the Thesium genome has not undergone additional rounds of whole-genome duplication, making it particularly tractable for studying gene family evolution. Our analyses reveal substantial loss of photosynthesis-related genes and contraction of biotic defense gene families, likely reflecting adaptation to a hemiparasitic lifestyle and reduced pathogen pressure at high altitudes. The absence of key root hair development genes correlates with the degenerate root hair phenotype observed in this species. Furthermore, hallmarks of high-altitude adaptation include the expansion of gene families involved in responses to hypoxia. Notably, expansion of gene families associated with meristem development is consistent with the presence of below-ground crown buds that enable rapid regeneration after mountain fires. Unexpectedly, we detected tandem duplication and diversification of the strigolactone receptor gene D14, which regulates secondary shoot formation, but not of its ancestral paralog KAI2, which mediates seed germination in response to the smoke-derived compound karrikin. This finding suggests divergent signaling mechanisms underlying fire adaptation across different parasitic plant lineages. By integrating time-series transcriptomic data, we propose a post-fire "defense first, repair later, recovery last" model, in which resources are reallocated from immediate defense to rapid repair and ultimately to long-term recovery, to explain the adaptation of T. ramosoides to fire-prone habitats. Our study provides critical insights into the complex and contrasting genomic dynamics that drive adaptation to multiple co-occurring selection pressures.

Genome, Plant↗
PubMed2025

The evolution of the plastid genomes in the holoparasitic Balanophoraceae.

The independent transition to a heterotrophic lifestyle in plants drove remarkably convergent evolutionary trajectories, characterized by morphological modifications and reductions in their plastomes. The characteristics of the minimum plastome required for survival, if they exist, remain a topic of debate. The holoparasitic family Balanophoraceae was initially presumed to have entirely lost their plastids, however, recent reports revealed the presence of reduced and aberrant plastids with odd genomes. Among the outstanding features of these genomes are the highest nucleotide composition bias across the tree of life and the only two genetic code changes ever recorded among plants. In this study, we assembled the plastomes from five genera, four of which had never been studied. Major common features include extremely high AT content, the lack of a typical quadripartite structure and extensive size reduction due to gene elimination and genome compaction. The family exhibits multiple gene and intron losses, and a broad range of scenarios regarding the evolution of the plastid trnE, a gene considered essential because of its dual function in tetrapyrrole biosynthesis and translation within the plastid. In addition, phylogenetic analyses suggest that the genus Scybalium is not monophyletic. An evolutionary model for the plastomes of the Balanophoraceae is proposed.

Genome, Plastid↗