Cloning and characterization of Somatic Embryogenesis Receptor Kinase I (EgSERK I) and its association with callus initiation in oil palm

• Published in: In vitro cellular & developmental biology. Plant Vol. 55; no. 2; pp. 153 - 164
• Main Authors: Lee, Fong-Chin, Ong-Abdullah, Meilina, Ooi, Siew-Eng, Ho, Chai-Ling, Namasivayam, Parameswari
• Format: Journal Article
• Language: English
• Published: New York Springer US 15.04.2019
• Subjects: Biomedical and Life Sciences; Cell Biology; Developmental Biology; Embryogenesis/Somatic Embryogenesis; Life Sciences; Plant Breeding/Biotechnology; Plant Genetics and Genomics; Plant Sciences; Callus induction; Embryogenic competence; Auxin; LRR-RLK protein; Somatic embryogenesis
• ISSN: 1054-5476; 1475-2689
• DOI: 10.1007/s11627-018-9942-x

The somatic embryogenesis receptor kinase ( SERK ) gene has been extensively studied in many plant species due to its role in conferring embryogenic competence to somatic cells. The oil palm ( Elaeis guineensis Jacq.) full-length SERK I ( EgSERK I ) cDNA was first isolated from cell suspension culture using RACE-PCR. Total length of EgSERK I cDNA was 2378 bp in length with a 5’UTR region (358 bp) longer than 3’UTR region (130 bp) and the ORF was 1890 bp (629aa). The deduced amino acid sequence of EgSERK I contained protein domains commonly present in reported SERK proteins, including the hallmark proline-rich region and C-terminal domains. EgSERK I was most highly expressed in leaf explants and also detected in all tested tissues, including vegetative tissues, reproductive tissues, embryogenic tissues, and non-embryogenic tissues, suggesting that it may have a broad role in plant growth and development. Expression of EgSERK I in leaf explant was upregulated by minimal auxin concentration at the initial 6 h of incubation in callus induction media. EgSERK I mRNA was detected in the adjacent cells of the vascular tissues in the midvein region of leaf explants which serves as the callus initiation point of callogenesis in oil palm. Collectively, our findings suggest that the EgSERK I gene is involved in the callus initiation stage of oil palm somatic embryogenesis by transducing the signal to switch on the dedifferentiation process, triggering cellular reprogramming to form callus.