How to Differentiate between Resistant and Susceptible Wheat Cultivars for Leaf Rust Fungi Using Antioxidant Enzymes and Histological and Molecular Studies?

Abstract

Eight wheat cultivars, Sakha-94, Giza-171, Sids-1, Sids-12, Sids-13, Shandweel-1, Misr-1, and Misr-2, were evaluated for leaf rust at the seedling and adult stages in the 2021 and 2022 seasons. Biochemical, histological, and genetic analyses were performed to determine the link between cultivars that were either sensitive or resistant to the disease. Misr-2 and Giza-171 cultivars had the highest levels of resistance to leaf rust races in 2021 (LTCGT, STSJT, and TTTST) and 2022 (MBGJT, TTTKS, and TTTTT) at the seedling stage. However, at the adult stage, Sakha-94, Giza-171, Misr-1, and Misr-2 cultivars had the highest levels of resistance; consequently, they had the lowest final disease severity and the lowest values of AUDPC. The correlation between the seedling reaction and adult reaction was non-significant, with values of 0.4401 and 0.4793 in the 2021 and 2022 seasons, respectively. Throughout the biochemical, histological, and genetic analyses, it was observed that catalase, peroxidase, and polyphenol oxidase activities significantly increased in the resistant cultivars. The discoloration of superoxide (O2-) and hydrogen peroxide (H2O2) significantly decreased in resistant and moderately resistant wheat cultivars (Sakha-94, Giza-171, Misr-1, and Misr-2); higher hydrogen peroxide (H2O2) and superoxide (O2-) levels were recorded for the susceptible cultivars compared to the resistant cultivars. Molecular markers proved that the Lr50 gene was detected in the resistant cultivars. Puccinia triticina infections negatively affected most histological characteristics of flag leaves, especially in susceptible cultivars. The thickness of the blade (µ), the thickness of the upper and lower epidermis (UE and LE), the thickness of mesophyll tissue (MT), and bundle length and width in the midrib were decreased in susceptible cultivars such as Sids-1, Sids-13, and Shandwel-1 compared with resistant cultivars.

Evaluation of Five Chrysanthemum morifolium Cultivars against Leaf Blight Disease Caused by Alternaria alternata at Rooting and Seedling Growth Stages

“…These results may explain why this cultivar is more tolerant to Alternaria infection compared to the other infected cultivars. A similar pattern has been observed on wheat plants under biotic stress [ 28 , 29 ]. Further studies are needed on the possible biocontrol of this disease in addition to using the resistant cultivar as identified in the current study.…”

“…The improvements in anatomical structures such as cuticle and cortex thickness and xylem vessel diameter are of importance as defence mechanisms against biotic and abiotic stresses. This has been shown for drought stress [ 46 ], water deficit stress [ 24 , 47 ], salt stress [ 26 ], and plant disease stresses [ 27 , 29 ]. The increase in cuticle thickness is an adaptational characteristic to tolerate the stressful conditions and protect the internal tissues [ 47 ].…”

“…A. alternata , as a common fungus species, is considered pathogenic in several important crop plants or an endophytic for many plants [ 22 ]. In many studies and with various plant species, anatomical parameters have been recorded as important to explain the changes in growth under various conditions including, water deficit [ 23 , 24 ], salt stress [ 25 , 26 ], and plant pathogens [ 27 , 28 , 29 ]. These changes in anatomical characters may help the plant to cope with stressful conditions and better tolerate plant pathogens.…”

Induced genetic diversity through mutagenesis in wheat gene pool and significant use of SCoT markers to underpin key agronomic traits

“…The seeds of three Egyptian cultivars of bread wheat ( Triticum aestivum ) , which are Sids1, Sids12, and Giza168, were obtained from the Field Crops Research Institute (FCRI), Agricultural Research Centre (ARC), Giza, Cairo, Egypt. The selection of these varieties is rooted in their widespread cultivation in Egypt, their high productivity, and their resilience to adverse conditions [ 26 , 83 , 84 ]. Table 5 shows the lineage and origin of these genotypes.…”