Protoplast Technology and Somatic Hybridisation in the Family Apiaceae

Species of the family Apiaceae occupy a major market share but are hitherto dependent on open pollinated cultivars. This results in a lack of production uniformity and reduced quality that has fostered hybrid seed production. The difficulty in flower emasculation led breeders to use biotechnology approaches including somatic hybridization. We discuss the use of protoplast technology for the development of somatic hybrids, cybrids and in-vitro breeding of commercial traits such as CMS (cytoplasmic male sterility), GMS (genetic male sterility) and EGMS (environment-sensitive genic male sterility). The molecular mechanism(s) underlying CMS and its candidate genes are also discussed. Cybridization strategies based on enucleation (Gamma rays, X-rays and UV rays) and metabolically arresting protoplasts with chemicals such as iodoacetamide or iodoacetate are reviewed. Differential fluorescence staining of fused protoplast as routinely used can be replaced by new tagging approaches using non-toxic proteins. Here, we focused on the initial plant materials and tissue sources for protoplast isolation, the various digestion enzyme mixtures tested, and on the understanding of cell wall re-generation, all of which intervene in somatic hybrids regeneration. Although there are no alternatives to somatic hybridization, various approaches also discussed are emerging, viz., robotic platforms, artificial intelligence, in recent breeding programs for trait identification and selection.

Automated summary

This study discusses the use of protoplast technology for the development of somatic hybrids, cybrids, and in-vitro breeding of commercial traits, including cytoplasmic male sterility (CMS), genetic male sterility (GMS), and environment-sensitive genic male sterility (EGMS). The molecular mechanism(s) underlying CMS and its candidate genes are also discussed. Various cybridization strategies and tagging approaches using non-toxic proteins are reviewed. The article also focuses on the initial plant materials and tissue sources for protoplast isolation, digestion enzyme mixtures, and cell wall re-generation, all of which play a role in somatic hybrids regeneration. Although there are no alternatives to somatic hybridization, emerging approaches such as robotic platforms and artificial intelligence are being used in recent breeding programs.