Aug 2026· Plant, Cell and Environment· 0 citations· 60 references
Medicine
TL;DR
These findings identify FIM2 and FIM3 as critical regulators of actin organisation, cell wall remodelling and vacuolar architecture during gall development, highlighting the importance of a balanced cytoskeleton dynamics for successful nematode parasitism.
Abstract
The plant cytoskeleton undergoes extensive remodelling during the formation of Meloidogyne incognita-induced giant cells and plays a crucial role in their ontogenesis. Fimbrins (FIMs) are a conserved family of actin-bundling proteins that regulate cytoskeletal architecture and dynamics during diverse cellular processes. However, their functional contribution to giant cell development remains unknown. Here, we show that all five Arabidopsis thaliana FIM genes (FIM1-FIM5) are expressed in M. incognita-induced galls, with expression levels declining as giant cells mature. Loss of function of FIM2 or FIM3, as well as FIM2 overexpression, altered actin organisation and giant cell morphology, resulting in reduced cytoplasmic density and cell wall stubs. These defects were associated with changes in cell wall composition and vacuolar organisation. FIM2 overexpression increased the accumulation of low-methyl-esterified homogalacturonan in giant cell walls, whereas fim2 and fim3 mutants showed reduced accumulation, consistent with altered cell wall thickness. Increased vacuolar sizes in INT1-eGFP Arabidopsis galls following latrunculin B treatment further indicates that actin organisation is required to maintain vacuolar architecture in giant cells. Moreover, fim2, fim3 and FIM2OE lines showed enhanced resistance to M. incognita, with reduced gall formation and egg mass production. Together, our findings identify FIM2 and FIM3 as critical regulators of actin organisation, cell wall remodelling and vacuolar architecture during gall development, highlighting the importance of a balanced cytoskeleton dynamics for successful nematode parasitism.
It is reported that NtProRP1, an extracellular protein, localizes to the cell wall immediately after fertilization in Nicotiana tabacum, uncovering a new mechanism for NtProRP1 in regulating early embryogenesis and delivering a unique transcriptomic resource that advances understanding of extracellular signaling in plant embryogenesis.
An Luo, Ying Qiao, Siyuan Li et al.· Plant and Cell Physiology· 0 citations
It is proposed that ILKs contribute to pathways connecting elicitor-triggered immune signaling with cell-wall-associated stress responses and that ILK-related defense functions may extend to the cotton root-nematode interaction, while the mechanism remains to be elucidated.
Gizem Dimlioglu, N. Nejat, Emily G Cooley et al.· Plant Science· 0 citations
Pollen wall formation requires precise coordination between tapetum differentiation, metabolism, and programmed cell death. In Arabidopsis, the microspore-derived peptide CLE19 restricts tapetal activity to maintain pollen wall homeostasis, yet how CLE19 signaling achieves developmental specificity and robustness remains unclear. Here, we identify the receptor-like kinase BARELY ANY MERISTEM 3 (BAM3) as an additional receptor for CLE19. Genetic, cytological, biochemical, and transcriptomic analyses showed that disruption of BAM3 signaling impairs tapetum differentiation, secretory homeostasis, and pollen exine patterning, resulting in selective transcriptional reprogramming during anther development. Comparative transcriptomic analyses reveal that BAM3 mediates a distinct subset of CLE19-responsive genes, including both AMS-dependent pathways governing tapetal degeneration and exine biosynthesis, and AMS-independent programs associated with flavonoid metabolism and pollen wall development. Biochemical assays, structure-guided mutagenesis, and AlphaFold3 modeling further support CLE19-dependent assembly of BAM3-SERK1/2 receptor complex, revealing a conserved molecular framework for CLE19 perception that is distinct from, yet complementary to, the previously characterized CLE19-PXL1-SERK1/2 receptor module. Together, these findings establish a dual-receptor architecture for CLE19 signaling in which BAM3 mediates a transcriptionally distinct branch of the CLE19 pathway. More broadly, this work demonstrates how combinatorial peptide-receptor usage expands the signaling capacity of a single developmental peptide to coordinate robust male reproductive development.
Wenhui Sun, S. Wang, Mengyu Li et al.· Plant Physiology· 0 citations
Root-knot nematodes (RKNs; Meloidogyne spp.) are destructive agricultural parasites, but although giant cell formation is required for establishing parasitism, the mechanism of action has not been fully elucidated. Spatial transcriptomics enables precise spatiotemporal analyses of gene expression, facilitating studies of cell heterogeneity. We performed spatial transcriptomic sequencing on Moneymaker tomato root galls caused by M. incognita infection at 3, 5, and 7 days post-inoculation to investigate RKN-induced giant cell formation. Five major cell types were identified; of these, giant cell clusters were localized predominantly in the xylem, stele, and meristem. Four novel giant cell-specific marker genes were confirmed through RNA in situ hybridization. Pseudotime analysis revealed genes potentially associated with giant cell formation. Virus-induced gene silencing (VIGS) of four genes encoding a cyclin-dependent kinase, two cell division cycle-associated proteins, and a MYB3R-1-like transcription factor—hypothesized to maintain the cell cycle or gene expression during mitosis—resulted in significantly fewer galls and significantly smaller giant cells. This study established the first spatiotemporal atlas of RKN-infected tomato roots and identified genes associated with giant cell formation, laying a foundation for further research on the establishment of RKN feeding sites, providing novel insights into RKN pathogenic mechanisms, and potentially guiding novel control strategies.
Lijun Jiang, Dan Chen, Qianqian Shi et al.· Molecular Horticulture· 0 citations
Auxin Response Factors (ARFs) are of vital importance in plant growth and vascular development. Class A ARFs are the core auxin-driven drivers of embryogenesis, vascular pattern development, (pro)cambial stem cell initiation and xylem cell fate specification, while class B ARFs may attenuate or fine-tune auxin-mediated development. The potential roles of class C ARFs in vascular development and xylogenesis, however, remain largely unexplored. In this study, we identified Eucalyptus grandis ARF10 (EgrARF10) as a potential regulator of secondary cell wall (SCW) development. We show that EgrARF10 is nucleus-localised and strongly associated with SCW biosynthetic genes and transcription factors across co-expression and multi-omic networks. Mining of published spatial and single cell transcriptomic data revealed preferential expression of EgrARF10 in vessel and fusiform organizer cells of secondary xylem tissue, while EgrARF10 orthologs in other species exhibit diverse cell type-specific expression ranging from root cap vascular and metaxylem to cork cambium. Heterologous overexpression of EgrARF10 in hybrid poplar did not alter overall growth or morphology but resulted in a significant reduction in stem lignification, accompanied by relative increases in D-glucose, D-xylose and D-mannose, indicating altered SCW composition. While the molecular mechanism by which EgrARF10 acts remains unknown, these findings provide the first evidence for the role of a class C ARF in xylem SCW biology.
Ipeleng Makhura, R. Ployet, A. Myburg et al.· Tree Genetics & Genomes· 0 citations
BACKGROUND AND AIMS
Magnesium is an essential mineral nutrient with numerous physiological roles in plant growth and development. However, the mechanisms of Mg2+ transport in Solanum lycopersicum remain largely unknown.
METHODS
In this study, we performed the characterization of the Magnesium Release family genes (SlMGRs) in tomato. The conserved evolutionary relationship and expression pattern of SlMGR genes, and the subcellular localization and Mg2+ transport activity of SlMGR proteins, were investigated.
KEY RESULTS
A total of ten SlMGR proteins were identified. They were divided into three subgroups based on their evolutionary relationship and subcellular localization. Four members in clade I were vacuolar localized, five members in clade II were plasma membrane localized, whereas SlMGR10, the sole member in clade III, was chloroplast envelope localized. SlMGR10 could successfully complement the growth defects of MM281, a bacterial Mg2+ uptake mutant, under Mg-limited conditions. It was also able to rescue the severe defects in embryo development and seedling growth of the Arabidopsis mgr8mgr9 double mutant caused by Mg deficiency during chloroplast development.
CONCLUSIONS
Our results demonstrated that SlMGR10 functioned as a chloroplast envelope Mg2+ transporter to mediate Mg2+ uptake for chloroplast in Solanum lycopersicum.
Zheng-Yang Lin, Xue-Qing Chen, Jin-Bo Wan et al.· Annals of Botany· 0 citations