Caracterização e expressão do gene SERK durante a indução de embriogênese somática em soja / Characterization and expression of SERK gene during induction of somatic embryogenesis in soybean

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

20/09/2010

RESUMO

Somatic embryogenesis is a useful tool for plant propagation and a suitable model system for deciphering early events during embryo development. Molecular and genetic studies focused in plant development have reported the involvement of SERK (Somatic Embryogenesis Receptor Kinase) gene in the acquisition of embryogenic competence. In order to increase the efficiency of plant regeneration processes we need to understand it better. Therefore, the purpose of the present work was to determine if the SERK gene is present in the soybean genome and analyze its expression during somatic embryogenesis. Genes encoding tree novel members of the Leucine-rich repeat receptor like kinase (LRR-RLK) superfamily have been identified. These genes was named GmSERK1, GmSERK2 and GmSERK3, since they share a conserved intron/exon structure with other members of the SERK family and encode a signal peptide, a leucine zipper domain, five LRR, the SPP domain, a single transmembrane domain and a kinase domain with 11 subdomains, features that distinguishes SERK proteins from other proteins belonging to the LRRRLK superfamily. To investigate the position of GmSERK proteins in the plant LRR-RLKs superfamily, the conserved parts of the extracellular or intracellular domains were compared to other published LRR-RLKs sequences taken from literature. In the LRR domain, SERK proteins share all conserved amino acids of the plant LRR consensus sequence. Moreover, conservations of an aspartic acid (D) at position 1, an asparagine (N) at position 4 and a glycine (G) at position 16 were observed, although they are not consensus between other LRRs. A phylogenetic tree was constructed based on kinase domains and results showed that SERK proteins form a distinct branch in the phylogenetic tree and GmSERKs clustered most closely with SERK gene members such as Medicago truncatula (MtSERK1), ix Teobroma cacao (TcSERK) and Solanum tuberosum (StSERK1). Treatment of explants with 2,4-dichlorophenoxyacetic acid (40 mg/L) was effective in inducing somatic embryos derived from the cultivar CAC-1 and a large number of globular embryos could be viewed after 30 days. However, it was observed a strong effect of the genotype in the morphogenic response. Unlike CAC-1, explants derived from the cultivar CS303 showed a low frequency of induction and only a small number of somatic embryos were obtained. Analysis of gene expression, performed by in situ hybridization, showed that a high level of GmSERK1 transcripts could be detected in embryogenic tissues of CAC-1 during the induction of somatic embryogenesis. In contrast, immature cotyledons of soybean cultivar CS303 showed low levels of GmSERK1 transcripts. These results suggest the involvement of GmSERK1 gene with somatic embryogenesis, probably acting as an important player in acquisition of embryogenic competence.

ASSUNTO(S)

aquisição de competência glycine max genetica molecular e de microorganismos somatic embryogenesis acquisition of competence. glycine max embriogênese somática

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