Biotechnological tools in the propagation and conservation of threatened species: An overview

Plant diversity is crucial for the balanced functioning of the environment, as humans are highly dependent on them since plants provide sustenance and services like regulation of climate and protection from natural hazards. At present, 20,360 plant species are threatened (critically endangered, endangered and vulnerable), 165 species are extinct and extinct in the wild, due to several factors as per International Union for Conservation of Nature (IUCN) data and their conservation is of utmost importance. The in vitro methodology has become one of the promising tools of biotechnology in the conservation of threatened plants. The technique ensures propagation of taxa with limited explant source, seed dormancy, self-incompatibility, inbreeding depression, etc. resulting in lower seed production. In vitro methods along with the ex situ and in situ methods have been extensively used in the conservation of plants. This review highlights a compilation of several biotechnological tools i.e., micropropagation, somatic embryogenesis, callus induction, organogenesis, cryopreservation, micrografting, employed in the conservation of over a hundred threatened species. Furthermore, the present review sheds light on the importance of genetic homogeneity assessment based on frequently used molecular markers amongst in vitro raised and the donor mother plants. The review will help other researchers to employ various tissue culture methods in conservation programs of threatened and rare plants.