Arabidopsis shaker pollen inward K+ channel SPIK functions in SnRK1 complex‐regulated pollen hydration on the stigma

• Published in: Journal of integrative plant biology 2017-09, Vol.59 (9), p.604-611
• Main Authors: Li, Dan‐Dan, Guan, Huan, Li, Fei, Liu, Chang‐Zhen, Dong, Yu‐Xiu, Zhang, Xian‐Sheng, Gao, Xin‐Qi
• Format: Article
• Language: English
• Subjects: Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - metabolism; Gene expression; Germination; Hydration; In vitro methods and tests; Kinases; Pollen; Pollen - physiology; Potassium - metabolism; Potassium channels; Protein kinase; Protein-Serine-Threonine Kinases - metabolism; Reactive oxygen species; Ribonucleic acid; RNA; Sequence Analysis, RNA; Shaker Superfamily of Potassium Channels - metabolism; Stigma; Water - physiology
• ISSN: 1672-9072; 1744-7909
• DOI: 10.1111/jipb.12563

Pollen hydration is a critical step that determines pollen germination on the stigma. KINβγ is a plant‐specific subunit of the SNF1‐related protein kinase 1 complex (SnRK1 complex). In pollen of the Arabidopsis kinβγ mutant, the levels of reactive oxygen species were decreased which lead to compromised hydration of the mutant pollen on the stigma. In this study, we analyzed gene expression in kinβγ mutant pollen by RNA‐seq and found the expression of inward shaker K+ channel SPIK was down‐regulated in the kinβγ pollen. Furthermore, we showed that the pollen hydration of the Arabidopsis spik mutant was defective on the wild‐type stigma, although the mutant pollen demonstrated normal hydration in vitro. Additionally, the defective hydration of spik mutant pollen could not be rescued by the wild‐type pollen on the stigma, indicating that the spik mutation deprived the capability of pollen absorption on the stigma. Our results suggest that the Arabidopsis SnRK1 complex regulates SPIK expression, which functions in determining pollen hydration on the stigma. Pollen hydration is a critical step that determines pollen germination on the stigma. In this study, we found that Arabidopsis SnRK1 complex regulates the expression of SPIK, a plasma membrane‐localized K+ channel, which functions in mediating pollen hydration on the surface of the stigma.