Abstract
Plant growth and metabolism are affected by various biotic and abiotic stimuli including microorganisms and insects attack as well as temperatural and hormonal effects. Unlike animals, plants cannot move independently and need a more complicated and efficient defense system against different stimuli. This thesis focused on the identification of three VrHsc70 proteins in Vigna radiata and the analyses of methyl jasmonate (MeJA)-induced genes in Bupleurum kaoi adventitious roots. Organisms often synthesize molecular chaperons to cope with stress such as heat, cold, wounding, heavy metals, and water deficit. The 70 kDa heat shock protein (Hsp70) and the constitutively expressed heat shock cognate (Hsc70) are conserved among all organisms. In addition, Hsp/Hsc70s have been found to be upregulated at specific developmental stages in the absence of stress. In the first part of this study, three mungbean Hsc70 cDNAs were isolated and their developmental expressions were characterized at both transcriptional and protein levels. Our results indicate that these three VrHsc70s may not be important in seed maturation or desiccation tolerance, but probably involved in normal growth and development. Jasmonic acid (JA) and MeJA are ubiquitous plant signaling compounds that play a key role in the regulation of metabolic processes, reproduction, and defense against pathogens and insects. In the second part of this study, MeJA was applied to adventitious root culture of B. kaoi and the expression profiles of induced genes were investigated. Our results indicate that MeJA has a complex signaling network involving a large-scale transcriptional reprogramming. Some of the MeJA-induced genes may have applications in agricultural, medicinal and food industries.