Preserving Genetic Diversity in Medicinal Plant Cultivation: Case Studies on Tripterygium wilfordii, T. hypoglaucum and Nypa fruticans

Abstract

Traditional and potential medicinal plants play a vital role in human health, but over-exploitation has resulted in biodiversity loss that raise global concerns. Moreover, there are no known breeding programs to improve their populations leaving them under threat from any form of disturbances. To secure a future sustainable supply, cultivation and domestication are proposed. Two case studies are presented here. First, the population genetics of Tripterygium wilfordii and T. hypoglaucum, reveals a distinct genetic divergence through DNA sequences and microsatellites. Tripterygium wilfordii exhibits lower diversity and subdivision than T. hypoglaucum, possibly due to migration rates and population history. Cultivated populations have reduced genetic diversity due to small sizes and vegetative propagation, underscoring diverse populations as primary important to conservation and breeding. The study highlights the use of various DNA markers to understand medicinal plant genetics. The second case study explores the genetic diversity of Nypa fruticans, a potential functional food and medicinal resource with an extensive distribution across the Indo-West Pacific region. Utilizing microsatellite markers, the research reveals significant genetic differentiation influenced by geographical distances. It identifies barriers and migration patterns, shedding light on the species' population structure and potential applications. Domestication involves artificial selection and genetic bottlenecking, leading to the loss of wild genetic diversity. This loss has serious implications, including reduced plasticity in secondary metabolism (a major source of medicinal compounds), diminished genetic diversity for compound yield improvement, reduced adaptability to changing environments, and negative impacts on sustainable use. Furthermore, the genetic diversity of promising medicinal plants, critical for new drug development, is rapidly declining due to over-harvesting. The problem of homonyms exacerbates this issue, damaging wild resources and plant diversity. To protect these resources and meet increasing demands, large-scale cultivation is urgently needed. Future cultivation strategies can be improved by studying genetic diversity in both wild and cultivated populations of these plant species.