Somatic Embryogenesis and Agrobacterium -Mediated Gene Transfer Procedures in Chilean Temperate Japonica Rice Varieties for Precision Breeding

• Published in: Plants (Basel) Vol. 13; no. 3; p. 416
• Main Authors: Barrera, Marion, Olmedo, Blanca, Zúñiga, Carolina, Cepeda, Mario, Olivares, Felipe, Vergara, Ricardo, Cordero-Lara, Karla, Prieto, Humberto
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 31.01.2024
• Subjects: 2,4-D; Agrobacterium; Auxins; Biotechnology; Climate change; Climate effects; cold-adapted rice; Cultivars; Cytokinins; Efficiency; Embryonic growth stage; Embryos; Fluorescence; geminivirus-derived vector; Gene transfer; Genetic engineering; Genetic modification; Genetic transformation; Genomes; Genotype & phenotype; Genotypes; Green fluorescent protein; Kinetin; mRNA; New technology; Plant breeding; Proteins; Regeneration; Reporter gene; Rice; Seeds; Somatic embryogenesis; T-DNA; cold-adapted rice; geminivirus-derived vector; genetic transformation
• ISSN: 2223-7747; 2223-7747
• DOI: 10.3390/plants13030416

Rice ( ) varieties are generated through breeding programs focused on local requirements. In Chile, the southernmost rice producer, rice productivity relies on the use and generation of temperate japonica germplasms, which need to be adapted to the intensifying effects of climate change. Advanced biotechnological tools can contribute to these breeding programs; new technologies associated with precision breeding, including gene editing, rely on procedures such as regeneration and gene transfer. In this study, the local rice varieties Platino, Cuarzo, Esmeralda, and Zafiro were evaluated for somatic embryogenesis potential using a process that involved the combined use of auxins and cytokinins. An auxin-based (2,4-D) general medium (2N6) allowed for the induction of embryogenic masses in all the genotypes. After induction, masses required culturing either in N6R (kinetin; Platino) or N6RN (BAP, kinetin, IBA, and 2,4-D; Cuarzo, Esmeralda, and Zafiro) to yield whole plants using regeneration medium (N6F, no hormone). The sprouting rates indicated Platino as the most responsive genotype; for this reason, this variety was evaluated for gene transfer. Fifteen-day-old embryo masses were assayed for -mediated transformation using the bacterial strain EHA105 harboring pFLC- / / , a modified T-DNA vector harboring a geminivirus-derived replicon. The vector included the green fluorescent protein reporter gene, allowing for continuous traceability. Reporter mRNA was produced as early as 3 d after agroinfiltration, and stable expression of the protein was observed along the complete process. These achievements enable further biotechnological steps in these and other genotypes from our breeding program.