INVESTIGATION OF SUSCEPTIBILITY AND RESISTANCE MECHANISMS OF SOME EGYPTIAN WHEAT CULTIVARS (Triticum aestivum L.) INOCULATED WITH Blumeria graminis f.sp. tritici USING CERTAIN BIOCHEMICAL, MOLECULAR CHARACTERIZATION AND SEM | ||||
| Journal of Plant Protection and Pathology | ||||
| Article 1, Volume 6, Issue 3, March 2015, Page 431-454 PDF (2.83 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jppp.2015.53305 | ||||
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| Authors | ||||
Y. M. Hafez  1; Kh. A.A. Abdelaal2
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| 1Plant Pathology Branch, Agricultural Botany Dept. | ||||
| 2Agricultural Botany Branch, Agricultural Botany Dept., Faculty of Agriculture, Kafrelsheikh University, Egypt | ||||
| Abstract | ||||
| Two greenhouse experiments were conducted in the greenhouse of Agricultural Botany Department, Faculty of Agriculture, Kafrelsheikh University, Egypt, during two seasons (2012-2013 and 2013-2014) to study biochemical, molecular characterization and SEM investigation of susceptibility and resistance mechanisms of ten Egyptian wheat cultivars (Sakha 93, Sakha 94, Sids 12, Sids 13, Giza 160, Giza 168, Giza 171, Misr 1, Misr 2 and Gemmiza 11) inoculated with Blumeria graminis f. sp. tritici fungus the causal organism of wheat powdery mildew.This disease one of most important diseases of wheat worldwide. Chemical and biological control methods are used routinely to control the disease. However, resistant cultivars are still the best control strategy. Consequently, characterization of susceptibility and resistance mechanisms is very important and required essentially. In wheat susceptible cultivars (Sakha 93, Sakha 94, Sids 12 and Sids 13), moderately susceptible (Giza 160), moderately resistant (Giza 168, Giza 171, Misr 1), resistant (Misr 2) and highly resistant cultivars Gemmiza 11) when inoculated with powdery mildew fungus, the percent of disease severity were significantly decreased in resistant cultivars compared with susceptible ones. Indeed the disease symptoms and electrolyte leakage were also significantly decreased in resistant cultivars. As well as levels of reactive oxygen species (ROS), such as superoxide (O2·-) and hydrogen peroxide (H2O2) significantly accumulated early 6 and 12 hours after inoculation (hai) in the resistant cultivars. Consequently, catalase (CAT), superoxide dismutase (SOD) and peroxidase (POX) enzyme activities were significantly stimulated at 24-72 hai. Significant increase of chlorophyll a and b concentrations was found. However, in the susceptible inoculated cultivars, the fungus was intensively colonized with huge quantity of conidia spores compared with the moderately resistant, resistant and highly resistant cultivars using scanning electron microscope (SEM). Molecular investigations using PCR (SSR) technique proved that the resistant gene Pm38 over expressed and accumulated in resistant cultivars not in susceptible ones. Expression of Pm38 gene was correlated with the resistance degrees. It can be recommended giving more attention to these new mechanisms of resistance to improve and find out new resistant cultivars which over expressed new resistant-mediated-ROS genes. | ||||
| Keywords | ||||
| Triticum aestivum L; Blumeria graminis f.sp. tritici; Scanning Electron Microscope (SEM); antioxidants; Resistant Pm38 gene; ROS | ||||
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