Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR KINASES1 and 2 Are Essential for Tapetum Development and Microspore Maturation

Abstract

Among the >200 members of the leucine-rich repeat receptor kinase family in Arabidopsis thaliana, only a few have been functionally characterized. Here, we report a critical function in anther development for the SOMATIC EMBRYOGENESIS RECEPTOR KINASE1 (SERK1) and SERK2 genes. Both SERK1 and SERK2 are expressed widely in locules until stage 6 anthers and are more concentrated in the tapetal cell layer later. Whereas serk1 and serk2 single insertion mutants did not show developmental phenotypes, serk1 serk2 double mutants were not able to produce seeds because of a lack of pollen development in mutant anthers. In young buds, double mutant anthers developed normally, but serk1 serk2 microsporangia produced more sporogenous cells that were unable to develop beyond meiosis. Furthermore, serk1 serk2 double mutants developed only three cell layers surrounding the sporogenous cell mass, whereas wild-type anthers developed four cell layers. Further confocal microscopic and molecular analyses showed that serk1 serk2 double mutant anthers lack development of the tapetal cell layer, which accounts for the microspore abortion and male sterility. Taken together, these findings demonstrate that the SERK1 and SERK2 receptor kinases function redundantly as an important control point for sporophytic development controlling male gametophyte production.

Update on Phosphorylation-Mediated Brassinosteroid Signaling Pathways

“…BAK1 is involved in a light-dependent cell death [21], pathogenesis [4,6,24,29,46,51,54], and male sporogenesis [2,12]. These reports support the notion that BAK1 can act in a BRI1-independent way by binding to different LRR-RLKs which bind different ligands.…”

Characterization and expression analysis of somatic embryogenesis receptor-like kinase genes from Phalaenopsis

“…The expression pattern of PhSERKs is reminiscent of their association with plant organ development as reported in other species. Moreover, AtSERK1 and 2 were reported to have redundant functions in sporophytic development and controlled male gametophyte production (Albrecht et al, 2005;Colcombet et al, 2005). Interestingly, PhSERK4 was preferentially expressed in pollinia as compared with other PhSERKs, and its expression peaked at the FB7 stage, when the anther was readily differentiated (Figure 4).…”

“…Indeed, transgenic Arabidopsis plants overexpressing AtSERK1 showed an enhanced capacity to initiate somatic embryogenesis during in vitro culture . Moreover, AtSERK1 and 2 play a role in male sporogenesis, particularly tapetum development (Albrecht et al, 2005;Colcombet et al, 2005). ZmSERK1 and 2 of maize are similar to carrot and Arabidopsis SERK genes and are expressed in embryogenic calli as well as male and female reproductive tissues (Baudino et al, 2001).…”

Viability and Action of CPL Lectin on <i>in Vitro</i> Germinability of Pollen Grains of <i>Malpighia emarginata</i> DC.—(Malpighiaceae)

“…Other authors [35][36][37] also found that RLK lectins appear to control the development of pollen development by regulating the endothecium, middle lamella and tapetum.…”