To delineate the major processes associated with short water scarcity in four tall fescue species, we examined their enzymatic and nonenzymatic antioxidant activity and FaSGR expression levels. Moreover, we examined the possibility of Agrobacterium-mediated transformation of Arabidopsis P5CS1 gene in tall fescue. According to the results, proline has been introduced as an important compatible osmolyte, so as to protect enzymes and cellular structures under water scarcity. In addition to that, superoxide dismutase (SOD) along with proline can be used as a core physiological indicator for the assessment of adaptability to environmental conditions. Results indicated that most of the superoxide that was produced as a result of drought stress was converted to H2O2 by SOD and subsequently detoxified by ascorbate peroxidase (APX) into H2O. Notably, the FaSGR transcript increased drastically over the course of the drought stress in Pixie and Mini-mustang, in contrast to jaguar and h–d, supporting the notion of Stay GReen (SGR)-mediated chlorophyll degradation in the less drought-tolerant cultivars. Different modulations of ROSs quenching system in tall fescue genotypes suggest that even one stress signal causes different signaling responses in different cultivars. The heterologous transformation of P5CS1 in Festuca arundinacea background, confirmed by PCR and transient GUS assay, most probably can improve tall fescue tolerance to drought stress.
Part of the book: Water Stress in Plants