“Defence reactions occurring in resistant (cv Gankezaomi)


“Defence reactions occurring in resistant (cv. Gankezaomi) and susceptible (cv. Ganmibao) muskmelon leaves were investigated after inoculating with Colletotrichum lagenarium. Lesion restriction

buy CHIR-99021 in resistant cultivars was associated with the accumulation of hydrogen peroxide (H2O2). The activity of antioxidants catalase (CAT) and peroxidase (POD) significantly increased in both cultivars after inoculation, while levels of both CAT and POD activity were significantly higher in the resistant cultivar. Ascorbate peroxidase (APX) increased in both cultivars after inoculation, and level of APX activity was significantly higher in the resistant cultivar. Glutathione reductase (GR) activity selleck products significantly increased in both cultivars following inoculation, but was higher in the resistant cultivar, resulting in higher levels of ascorbic acid (AsA) and reduced glutathione (GSH). Phenylalanine ammonia lyase (PAL) significantly increased in inoculated leaves of both cultivars, resulting in higher levels of total phenolic compounds and flavonoids. The pathogenesis-related proteins chitinase (CHT) and β-1, 3-glucanase (GLU) significantly increased following inoculation with

higher activity in the resistant cultivar. These findings show that resistance of muskmelon plants against C. lagenarium is associated with the rapid accumulation of H2O2, resulting in altered cellular redox status, accumulation of pathogenesis-related proteins, activation of phenylpropanoid pathway to accumulation of phenolic compounds and flavonoids. Anthracnose, caused by Colletotrichum lagenarium, is one of the most destructive diseases of muskmelon, causing severe losses MCE in the field during warm and rainy weather (Langston 1999). The pathogen is hemibiotrophic and leads to spreading circular, necrotic spots on the leaves that develop into shot-hole lesions and deformed leaves (Ge and Guest 2011). In this study, we investigate the differences in the mechanisms in resistant and susceptible

cultivar. One of the factors associated with disease resistance in many plants is the rapid generation of reactive oxygen species (ROS) (Shetty et al. 2008). ROS have direct antimicrobial activity and play an important role in cellular signalling for mediating other defence responses (Madadkhah et al. 2012), including the oxidative cross-linking of plant cell walls (Shetty et al. 2008), callose deposition (Luna et al. 2011) and hypersensitive cell death (Lam 2004). However, over production of ROS could damage the host cells. To minimize the damaging effects of ROS, plants have evolved various enzymatic antioxidants such as APX, CAT and GR, and the non-enzymatic antioxidants AsA and GSH (Foyer and Noctor 2009). Pathogenesis-related proteins CHT (PR-3, PR-8, PR-11) and GLU (PR-2) synergistically catalyse the degradation of microbial cell wall polysaccharides (Roberti et al. 2008).

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