Cloning and Molecular Characterization of a SERK Gene Transcriptionally Induced During Somatic Embryogenesis in Ananas comosus cv. Shenwan

Abstract

A somatic embryogenesis receptor-like kinase (SERK) gene, designated as AcSERK1, was isolated from pineapple (Ananas comosus cv. Shenwan). AcSERK1 shared all the characteristic domains of the SERK family, including five leucine-rich repeats, one proline-rich region motif, transmembrane domain, and kinase domains. Somatic embryogenic cultures of pineapple were established following transfer of callus cultures to Murashige and Skoog (1962) medium containing 2,4-dichlorophenoxyacetic acid. The role of AcSERK1 during establishment of somatic embryogenesis in culture was investigated. The AcSERK1 was highly expressed during embryogenic competence acquisition and global embryo formation in culture. These findings were obtained along with morphological changes in callus cultures exhibiting embryogenic potential. Overall, levels of expression of AcSERK1 were lower in nonembryogenic tissues and organs than in embryogenic callus. In situ hybridization analysis revealed that AcSERK1 expression was detected in embryogenic tissues, including single competent cells, meristematic centers wherein embryogenic structures are formed, and global embryos. These results suggested that AcSERK1 expression was associated with induction of somatic embryogenesis and that it could be used as a potential marker gene to monitor the transition of pineapple callus tissues into competent and embryogenic cells and tissues.

Characterization and expression analysis of AcSERK2, a somatic embryogenesis and stress resistance related gene in pineapple

“…This gene can be used as a marker of embryogenic competent cells (Ma et al, 2012). In present study, another SERK gene, AcSERK2, was identified in pineapple.…”

“…1a). This exon/intron structure is quite similar to AcSERK1 (Ma et al, 2012) and other SERKs (Sharma et al, 2008;Stone et al, 2001). Each LRR domain is encoded by a separate exon, except for LRR2 and LRR3, which shared a single exon.…”

“…AcSERK2 clustered together with CnSERK (Pérez-Núňez et al, 2009), AcSERK1 (Ma et al, 2012), OsSERK (Hu et al, 2005) and ZmSERK1 (Baudino et al, 2001), and it clustered closer to AtSERK1, 2 than AtSERK3-5. These results suggested that AcSERK2 probably play a role in SE as which has been proposed for the orthologs in these species.…”

“…Usually, an auxin is required to induce SE, and subsequent auxin withdrawal or lowering of the auxin concentration is required for embryo maturation (Dudits et al, 1991). For example, 2,4-D is necessary and essential for Ananas comosus SE (He et al, 2010;Ma et al, 2012). In addition to their basic role in somatic embryogenesis, OsSERK1, OsBISERK1 and MaSERK1are reported to partially mediate defense signal transduction leading to disease resistance (Hu et al, 2005;Huang et al, 2010;Song et al, 2008).…”

Isolation and Expression Analysis of a SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE (SERK) Gene in Curcuma alismatifolia Gagnep.

“…The involvement of SERK proteins in regulating somatic embryogenesis was first described for DcSERK in embryogenic cell suspension cultures of carrot more than 15 years ago (Schmidt et al, 1997). Since then SERK gene homologs have been identified and their role in mediating somatic embryogenesis demonstrated in several monocot and dicot species such as Arabidopsis thaliana , Medicago truncatula (Nolan et al, 2003), Triticum aestivum (Singla et al, 2008), Vitis vinifera (Maillot et al, 2009), Cocos nucifera (Pérez-Núñez et al, 2009), Ananas comosus (Ma et al, 2012) and Cyrtochilum loxense (Cueva et al, 2012). Moreover, a gymnosperm SERK homolog has recently been discovered and its association with somatic embryogenesis was shown (Steiner et al, 2012).…”