Expression of the alfalfa gene MsMDHAR increases root biomass and promotes tolerance to hydric stress in transgenic Arabidopsis.

JAIME CL.; DEZAR C.; PAGÁN MUÑOZ I. ; DUNGER G.

Rosario

Congreso; RAFV Conference 2023; 2023

SAFV

Alfalfa (Medicago sativa L.) is the world's main forage crop, forming the basis for meat and milk production. Argentina is one of the leading alfalfa producers globally, with 3.5 million cultivated hectares. However, its persistence has decreased over the years due to climatic variations, soil degradation, and the relocation of its production to marginal areas.The ascorbate-glutathione pathway is a critical component of the plant defence system and it is responsible for regulating the cellular redox state, which is critical for maintaining cell function and survival under adverse conditions. Monodehydroascorbate reductase (MDHAR) is an essential enzyme of this cycle, being responsible for the regeneration of ascorbate, which is a potent antioxidant molecule. To study the function of MsMDHAR and its possible role in conferring hydric stress tolerance, we expressed this gene constitutively in Arabidopsis thaliana.First, the expression of MsMDHAR in different homozygous transgenic events of Arabidopsis was measured, and two of them were selected for phenotyping under control and abiotic stress conditions. It was found that transgenic plants developed more root biomass in control or hyperosmolarity conditions. To evaluate abiotic stress tolerance in the MsMDHAR-expressing Arabidopsis, plants were grown for 3 weeks in a greenhouse and then subjected to drought and waterlogging during two additional weeks. After that, dry weight of the rosette, inflorescence and seed production of the transgenic lines were evaluated. Expression of MsMDHAR seems to increase tolerance to drought and waterlogging in Arabidopsis, indicating that this enzyme plays an important role in plant stress responses. These preliminary results provide a basis for the development of alfalfa lines with improved tolerance to abiotic stresses via the manipulation of MsMDHAR expression.