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Updated: Jul 10, 2025

Author Spotlight: A High-Resolution, Single-Grain, In Vivo Pollen Hydration Bioassay for Arabidopsis thaliana
Published on: June 30, 2023
The Arabidopsis GPI-anchored protein COBL11 is necessary for regulating pollen tube integrity
Hongxia Li1, Yang Yang1, Hongkai Zhang1
1MOE Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
Abstract:
Pollen tube integrity is required for achieving double fertilization in angiosperms. The rapid alkalinization factor4/19-ANXUR1/2-Buddha's paper seal 1/2 (RALF4/19-ANX1/2-BUPS1/2)-complex-mediated signaling pathway is critical to maintain pollen tube integrity, but the underlying mechanisms regulating the polar localization and distribution of these complex members at the pollen tube tip remain unclear. Here, we find that COBRA-like protein 11 (COBL11) loss-of-function mutants display a low pollen germination ratio, premature pollen tube burst, and seed abortion in Arabidopsis. COBL11 could interact with RALF4/19, ANX1/2, and BUPS1/2, and COBL11 functional deficiency could result in the disrupted distribution of RALF4 and ANX1, altered cell wall composition, and decreased levels of reactive oxygen species in pollen tubes. In conclusion, COBL11 is a regulator of pollen tube integrity during polar growth, which is conducted by a direct interaction that ensures the correct localization and polar distribution of RALF4 and ANX1 at the pollen tube tip.
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