1Unidad de Biología Integrativa, Centro de Investigación Científica de Yucatán, A.C., calle 43 No. 130 x 32 y 34, Chuburná de Hidalgo, C.P. 97205, Mérida, Yucatán, México
2Unidad de Biotecnología, Centro de Investigación Científica de Yucatán, A.C., calle 43 No. 130 x 32 y 34, Chuburná de Hidalgo, C.P. 97205, Mérida, Yucatán, México
*Corresponding author’s email: islasign@cicy.mx
Received: 28 November 2024/ Accepted: 23 May 2025/ Published Online: 31 May 2025
Abstract
Highly methyl-esterified pectin (HME-P) is typically found in the primary cell walls of young and embryonic plant cells, where it plays a role in regulating differentiation and maturation processes. In this study, the JIM7 monoclonal antibody, which specifically targets HME-P, was utilized to examine tissue sections of coconut zygotic embryos and solid endosperms from the Yucatan green dwarf cultivar at various developmental stages. The expression of the pectin methyl-esterase gene was also assessed using RT-qPCR. The JIM7 antibody revealed the presence of HME-P surrounding the inner cells of immature embryos at the globular and coleoptile stages. As the embryos progressed to intermediate and mature stages, HME-P was found in various cell types, including those of the plumule. In the immature solid endosperm, HME-P was associated with syncytial cells. At the intermediate stage, it was observed in vesicle-like structures and by the mature stage, it surrounded compact cells in a distinct mosaic pattern, near the corrosion cavity. Analysis of the coconut PME gene expression in solid endosperm and zygotic embryos showed peak expression at the immature stage, followed by a decline at the intermediate and mature stages. These findings were consistent with the immunodetection results obtained with the JIM7 antibody in embryos and endosperms. Overall, this study provides novel insights into the coordinated expression of the PME gene and the dynamics of HME-P during the maturation of coconut zygotic embryos and solid endosperms. These findings suggest a potential role for pectin methyl esterification in zygotic embryogenesis in coconut.
