Fuente: PubMed "pollen" Plant Sci. 2026 Apr 15:113155. doi: 10.1016/j.plantsci.2026.113155. Online ahead of print.ABSTRACTPollen receptor-like kinases (PRKs) are known to regulate pollen development and pollen tube growth (PTG). However, the composition and functional characterization of the PRKs family members in Rosaceae species remain largely unexplored. In this study, 143 PRKs across 23 Rosaceae species were identified, undergoing approximately 2000 duplication events, and classified into subclass A, B, C and D, with members within each subclass exhibiting relatively conserved gene structure. Tissue-specific expression analysis revealed that PbrPRK1, -2, -3, -6, -7 and -8 in Pyrus bretschneideri exhibited pollen- and pollen tube (PT) -specific high expression. Subcellular localization analysis indicated PbrPRK1, -2, -3, -6, -7 and -8 are localized to the plasma membrane. Transient knockdown expression of PbrPRK1, -2, -3, -6 and -7 via antisense oligodeoxynucleotides significantly depolymerizate PT apical actin cytoskeleton and reduce tip-localized reactive oxygen species (ROS) accumulation to increase tip diameter, elevate burst rate, and short PT length. Furthermore, bimolecular fluorescence complementation and yeast two-hybrid assay demonstrated that the extracellular domains of PbrPRK3 and PbrPRK7 specifically interact with the pollen-secreted peptides PbrPOE6, -29, -41 and PbrPOE21, respectively. Suppressing the expression of PbrPRK3 and PbrPRK7 disrupted the regulatory effects of exogenously applied recombinant PbrPOE6, -29, -41 and PbrPOE21 proteins on ROS levels and actin cytoskeleton organization at the pollen tube tip. Our results suggested that PbrPRKs require PbrPOEs-mediated signaling to regulate PTG through modulating apical homeostasis of ROS and the actin cytoskeleton. This study provides evidence for the role of the POE-PRK module in regulating PTG and offers novel insights into cellular polar growth.PMID:41997500 | DOI:10.1016/j.plantsci.2026.113155