The RALF signaling pathway regulates cell wall integrity during pollen tube growth in maize

article The RALF signaling pathway regulates cell wall integrity during pollen tube growth in maize published yes Liang-Zi Zhou author Lele Wang author Xia Chen author Zengxiang Ge author f43371a3-09ff-11eb-8013-bd0c6a2f6de80000-0001-9381-3577 Julia Mergner author Xingli Li author Bernhard Küster author Gernot Längst author Li-Jia Qu author Thomas Dresselhaus author Autocrine signaling pathways regulated by RAPID ALKALINIZATION FACTORs (RALFs) control cell wall integrity during pollen tube germination and growth in Arabidopsis (Arabidopsis thaliana). To investigate the role of pollen-specific RALFs in another plant species, we combined gene expression data with phylogenetic and biochemical studies to identify candidate orthologs in maize (Zea mays). We show that Clade IB ZmRALF2/3 mutations, but not Clade III ZmRALF1/5 mutations, cause cell wall instability in the sub-apical region of the growing pollen tube. ZmRALF2/3 are mainly located in the cell wall and are partially able to complement the pollen germination defect of their Arabidopsis orthologs AtRALF4/19. Mutations in ZmRALF2/3 compromise pectin distribution patterns leading to altered cell wall organization and thickness culminating in pollen tube burst. Clade IB, but not Clade III ZmRALFs, strongly interact as ligands with the pollen-specific Catharanthus roseus RLK1-like (CrRLK1L) receptor kinases Zea mays FERONIA-like (ZmFERL) 4/7/9, LORELEI-like glycosylphosphatidylinositol-anchor (LLG) proteins Zea mays LLG 1 and 2 (ZmLLG1/2) and Zea mays pollen extension-like (PEX) cell wall proteins ZmPEX2/4. Notably, ZmFERL4 outcompetes ZmLLG2 and ZmPEX2 outcompetes ZmFERL4 for ZmRALF2 binding. Based on these data, we suggest that Clade IB RALFs act in a dual role as cell wall components and extracellular sensors to regulate cell wall integrity and thickness during pollen tube growth in maize and probably other plants. https://creativecommons.org/licenses/by-nc-nd/4.0/ Oxford University Press2024 eng Cell BiologyPlant Science The Plant Cell 1040-4651 1532-298X 3814222910.1093/plcell/koad324 365 yes L.-Z. Zhou et al., “The RALF signaling pathway regulates cell wall integrity during pollen tube growth in maize,” The Plant Cell, vol. 36, no. 5. Oxford University Press, 2024. Zhou L-Z, Wang L, Chen X, Ge Z, Mergner J, Li X, Küster B, Längst G, Qu L-J, Dresselhaus T. 2024. The RALF signaling pathway regulates cell wall integrity during pollen tube growth in maize. The Plant Cell. 36(5), koad324. Zhou, Liang-Zi, Lele Wang, Xia Chen, Zengxiang Ge, Julia Mergner, Xingli Li, Bernhard Küster, Gernot Längst, Li-Jia Qu, and Thomas Dresselhaus. “The RALF Signaling Pathway Regulates Cell Wall Integrity during Pollen Tube Growth in Maize.” The Plant Cell. Oxford University Press, 2024. <a href="https://doi.org/10.1093/plcell/koad324">https://doi.org/10.1093/plcell/koad324</a>. Zhou L-Z, Wang L, Chen X, et al. The RALF signaling pathway regulates cell wall integrity during pollen tube growth in maize. The Plant Cell. 2024;36(5). doi:<a href="https://doi.org/10.1093/plcell/koad324">10.1093/plcell/koad324</a> Zhou, L.-Z., Wang, L., Chen, X., Ge, Z., Mergner, J., Li, X., … Dresselhaus, T. (2024). The RALF signaling pathway regulates cell wall integrity during pollen tube growth in maize. The Plant Cell. Oxford University Press. <a href="https://doi.org/10.1093/plcell/koad324">https://doi.org/10.1093/plcell/koad324</a> L.-Z. Zhou, L. Wang, X. Chen, Z. Ge, J. Mergner, X. Li, B. Küster, G. Längst, L.-J. Qu, T. Dresselhaus, The Plant Cell 36 (2024). Zhou, Liang-Zi, et al. “The RALF Signaling Pathway Regulates Cell Wall Integrity during Pollen Tube Growth in Maize.” The Plant Cell, vol. 36, no. 5, koad324, Oxford University Press, 2024, doi:<a href="https://doi.org/10.1093/plcell/koad324">10.1093/plcell/koad324</a>. 147262024-01-02T11:19:37Z2024-07-16T11:18:46Z