Identification of Monodehydroascorbate Reductase (MDHAR) Genes in Garlic (Allium sativum L.) and Their Role in the Response to Fusarium proliferatum Infection

Monodehydroascorbate reductase (MDHAR) catalyzes the reduction of monodehydroascorbic acid, formed as a result of reactive oxygen species neutralization to ascorbic acid, which is one of the main mechanisms for maintaining the intracellular redox status. Three MDHAR genes encoding monodehydroascorbate reductases of different cellular localization are identified in the garlic genome (Allium sativum L.). The Pyr_redox_2 domain, the domains of binding with FAD and NAD(P)H cofactors, and a unique long loop motif required for the enzyme active site formation were identified in the amino acid sequences AsMDHAR1, AsMDHAR4, and AsMDHAR5. The expression profiles of MDHAR1, MDHAR4, and MDHAR5 genes in various organs of a garlic plant were determined, and the alteration in the transcription levels of AsMDHARs in response to infection with the pathogen Fusarium proliferatum was studied. The maximum AsMDHARs transcription was shown in leaves, pseudostem, and, in the case of AsMDHAR1, in roots. In response to infection with F. proliferatum, an increase in the transcription of all three AsMDHAR genes in the roots of garlic plants was revealed, while the activation of the genes was similar and did not depend on the degree of cultivar resistance to Fusarium rot.