Vol.:(0123456789) 1 3 Planta (2020) 252:39 https://doi.org/10.1007/s00425-020-03443-w ORIGINAL ARTICLE SERK genes identifcation and expression analysis during somatic embryogenesis and sporogenesis of sexual and apomictic Brachiaria brizantha (Syn. Urochloa brizantha) Andréa D. Koehler 1,2,3  · André S. T. Irsigler 2  · Vera T. C. Carneiro 2  · Glaucia B. Cabral 2  · Júlio C. M. Rodrigues 2  · Ana Cristina M. M. Gomes 2  · Roberto C. Togawa 2  · Marcos M. C. Costa 2  · Adriana Pinheiro Martinelli 1  · Diva Maria de Alencar Dusi 2 Received: 29 March 2020 / Accepted: 7 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Main conclusion In Brachiaria brizantha BbrizSERK1, BbrizSERK2 and BbrizSERK3 were identified. SERK expression marks somatic embryogenesis, sexual MMC, and sexual and apomictic PMC. BbrizSERK3 might have a regulatory role in reproductive development. Abstract Somatic embryogenesis receptor-like kinase (SERK) consists of plasma membrane receptor genes that have been characterized in various species, associated with several aspects of plant development, including reproduction. SERK genes are involved in anther development and in early embryo development in sexual and asexual seed formation. To comprehend the complexity of the SERK genes and their function in Brachiaria reproduction, we performed a homology-based search in a genomic database of a sexual B. brizantha and identifed sequences of three SERK genes, BbrizSERK1, BbrizSERK2, and BbrizSERK3. RNASeq data showed equivalent abundance of BbrizSERK1 and BbrizSERK2 transcripts in ovaries at early megasporogenesis of sexuals and apomicts, while BbrizSERK3 transcripts were more abundant in ovaries of sexuals than in apomicts. BbrizSERK3 results in three coding sequences due to alternative splicing, among them Variant 1 results in a protein with all the predicted domains of a SERK. BbrizSERK transcripts were detected in male reproductive tissues of both sexual and apomictic plants, suggesting a role in controlling anther development. BbrizSERK transcripts were detected early in ovule development, in the integuments, and in the megaspore mother cell of the sexual plant, but not in the cells that give rise to apomictic embryo sacs, suggesting a role in female reproductive development of sexuals. This paper provides evidences that SERK genes plays a role in the onset and establishment of somatic embryogenesis and in the reproductive development of B. brizantha and suggests a distinct role of BbrizSERK in apomixis initiation. Keywords Apomixis · Forage grass · Gene splicing · Megasporogenesis · Microsporogenesis · Plant reproduction Abbreviations AI Aposporic initials MMC Megaspore mother cell PMC Pollen mother cell SERK Somatic embryogenesis receptor-like kinase Communicated by Dorothea Bartels. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00425-020-03443-w) contains supplementary material, which is available to authorized users. * Adriana Pinheiro Martinelli adriana@cena.usp.br * Diva Maria de Alencar Dusi diva.dusi@embrapa.br 1 University of Sao Paulo, CENA, Av. Centenario 303, Piracicaba, SP 13416-903, Brazil 2 Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx.Postal 02372, Brasília, DF 70770-917, Brazil 3 Present Address: Linhares, Brazil