Cui et al. found new vital players in regulating anther development. The Plant Cell (2018). https://doi.org/10.1105/tpc.17.00586
By Yanwei Cui and Xiaoping Gou
Background: Anther is the male organ to produce pollen for pollination in angiosperms. The archesporial cells in early anther divide periclinally to generate the inner primary sporogenous cells and the outer primary parietal cells. The primary parietal cells subsequently undergo divisions to finally generate three layers of anther wall cells: the endothecium, the middle layer and the tapetum, surrounding the microspore mother cells (MMCs) that are developed from the primary sporogenous cells. We know that receptor-like protein kinases (RLKs) BARELY ANY MERISTEM 1/2 (BAM1/2) regulate the asymmetrical division of the archesporial cells, and RECEPTOR-LIKE PROTEIN KINASE 2 (RPK2) control the proper specification of the middle layer. However, we know relatively little about the molecular mechanisms of BAM1/2- and RPK2-mediated signalling pathways in regulating anther development.
Question: We wanted to know whether other RLKs function with BAM1/2 and RPK2 to regulate anther development. We tested this by shutting down RLK genes in the model plant Arabidopsis.
Findings: We found that four RLKs, named as CLAVATA3 INSENSITIVE RECEPTOR KINASE 1 (CIK1) to CIK4, are required for proper anther development in Arabidopsis. When these CIKs were destroyed, no viable pollen grains can be produced because normal anther cannot be formed. Detailed microscopic analyses revealed that divisions of the archesporial cells and the parietal cells are affected in early anthers of cik mutants, resulting in defective anthers lacking one to three cell layers of anther wall. We demonstrated that CIKs function as co-receptors of BAM1/2 and RPK2 to regulate division of the archesporial cells and control specification of the parietal cells during anther development in Arabidopsis.
Next steps: The corresponding ligands of these RLKs in controlling early anther development are still unknown. Moreover, little is known for the downstream signalling components of these RLK-mediated pathways. Efforts on these questions will provide important insights into understanding early anther development.
Title: Receptor kinases control anther cell differentiation.
Author(s) and Institutions: Yanwei Cui, Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University; Xiaoping Gou, Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University.
Yanwei Cui, Chong Hu, Yafen Zhu, Kaili Cheng, Xiaonan Li, Zhuoyun Wei, Li Xue, Fang Lin, Hongyong Shi, Jing Yi, Suiwen Hou, Kai He, Jia Li, Xiaoping Gou. (2018). CIK Receptor Kinases Determine Cell Fate Specification during Early Anther Development in Arabidopsis. Plant Cell. 30: 2383-2401; DOI: https://doi.org/10.1105/tpc.17.00586
Key words: Receptor-like kinase, anther development, cell differentiation.