Control of anther cell differentiation: a teamwork of receptor-like kinases.

Successful sexual reproduction depends on normal cell differentiation during early anther development in flowering plants. The anther typically has four lobes, each of which contains highly specialized reproductive (microsporocyte) and somatic cells (epidermis, endothecium, middle layer, and tapetum). To date, six leucine-rich repeat receptor-like protein kinases (LRR-RLK) have been identified to have roles in regulation of anther cell patterning in Arabidopsis thaliana. EXCESS MICROSPOROCYTES1 (EMS1)/EXTRA SPOROGENOUS CELLS (EXS) and SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASES1/2 (SERK1/2) signal the differentiation of the tapetum. BARELY ANY MERISTEM1/2 (BAM1/2) defines anther somatic cell layers, including the endothecium, middle layer, and tapetum. Moreover, RECEPTOR-LIKE PROTEIN KINASE2 (RPK2) is required for the differentiation of middle layer cells. In addition to process of anther cell differentiation, conserved regulation of anther cell differentiation in different plant species, this review mainly discusses how these receptor-like kinases and other regulators work together to control anther cell fate determination in Arabidopsis.