LlSR28 is involved in pollen germination by affecting filamentous actin dynamics

Area of Science:

• Plant molecular biology
• Gene regulation
• Pollen development

Background:

• Alternative splicing is crucial for gene regulation and protein diversity.
• Members of the villin/gelsolin/fragmin superfamily are known to undergo alternative splicing.
• Serine/arginine-rich (SR) proteins are key regulators of alternative splicing.

Purpose of the Study:

• To investigate the function of a lily SR protein (LlSR28) in plant development.
• To determine the role of Arabidopsis SR45 (AtSR45) in pollen germination and actin dynamics.
• To explore the relationship between SR proteins, alternative splicing, and actin-binding proteins in pollen.

Main Methods:

• Isolation and characterization of lily SR protein LlSR28.
• Complementation assay using Arabidopsis SR45 loss-of-function mutant (atsr45-1).
• Overexpression of LlSR28 and analysis of atsr45-1 mutant phenotypes, including pollen germination and F-actin content.
• Alternative splicing analysis of Arabidopsis villin1 (AtVLN1) and other actin-binding proteins (ABPs) in pollen.

Main Results:

• LlSR28 overexpression completely inhibited Arabidopsis pollen germination.
• The atsr45-1 mutant exhibited earlier pollen germination compared to wild-type.
• Pollen from atsr45-1 mutants showed reduced F-actin levels and altered alternative splicing of AtVLN1 and other ABPs.

Conclusions:

• LlSR28 likely affects F-actin dynamics through its alternative splicing activity.
• AtSR45 plays a critical role in regulating pollen germination by influencing actin dynamics and the expression of ABPs.
• LlSR28 may function similarly to AtSR45 in regulating alternative splicing and actin-related processes in plants.