Oryzalin-Mediated Artificial Polyploid Induction in Origanum vulgare L.: A Medicinal plant from the Lamiaceae Family

B.Sc. Mitali Paul

Master's thesis

Abstract:

The current study marks a substantial breakthrough by reporting the first successful creation of autopolyploid Origanum vulgare L. (commonly known as oregano) varieties using oryzalin treatment under in vitro conditions. The main aims were to explore O. vulgare’s response to oryzalin treatment, with particular attention to polyploid formation, subsequent phenotypical and gene expression changes, as well as its value for agriculture and medicine. Six different treatments were applied to a total of 312 plants, resulting in only eleven autopolyploid variants. Among them, two autopolyploids (Poly C and Poly 12, based on their performance under in vitro conditions) were further chosen for subsequent analyses. The low success rate illustrated the challenges of inducing autopolyploidy with oryzalin in oregano. Survival rates reduced with increasing oryzalin concentration. The autopolyploid plants exhibited larger leaves and stomata, hypothetically indicating improved resource utilization and water conservation. Physiological parameters assessment also showed alterations in membrane integrity, photosynthetic efficiency, and nutrient uptake parameters in the polyploid genotypes. Additionally, gene expression analysis showed enhanced expression of terpene synthase and cinnamate 4-hydroxylase in polyploid plants, suggesting heightened production of essential oils and bioactive compounds. The practical implications of the current study include the potential for novel cultivars with improved traits for agriculture and higher medicinal value. However, it is also note-worthy that there are also some associated challenges such as low success rates and limited generalizability. Hence, there is a need for further optimization and validation. Based on these, the future research directions might involve combined transcriptomic-metabolomic studies to reveal the key genes and pathways associated with secondary metabolite biosynthesis. Additionally, we also propose considering the environmental effects, reference gene selection, and comparative efficacy studies, to augment the study's applicability and relevance.

Keywords

Flow cytometry, Gene expression, Induced polyploidy, In vitro propagation, Medicinal plants, Mint family

Language used: English

Date on which the thesis was submitted / produced: 28. 4. 2024

Thesis defence

• Date of defence: 6. 6. 2024
• Supervisor: prof. Ing. Eloy Fernández Cusimamani, Ph.D.
• Reader: Aninda Mazumdar, externi

Czech University of Life Sciences Prague

Faculty of Tropical AgriSciences

Master programme:
Tropical Farming Systems