The study of Chitinase gene expression during infection of wheat near isogenic lines carrying Lr34/Yr18 locus to stripe and leaf rust pathogens

Leaf and stripe rust known as destructive disease of wheat word wide. One of the strategies to control these diseases is employing slow rusting gene which confers resistance in long period، different climate and against various fungi races. Through slow rusting genes have been introduced yet، Yr18/Lr34 is the most important locus because resistance derived is not broken down in most of the wheat growing areas. Indeed، Yr18//Lr34 locus confer resistance at least to six different pathogen including stripe rust، leaf rust، stem rust، powdery mildew، barley yellow dwarf virus as well as spot blotch of wheat. Chitinase belong to defense response cluster and is up-regulated post-inoculation of pathogen in the plant cells. Quantitative real-time PCR has been employed to study the expression profile of Chitinase post-inculcation of leaf and stripe rust at seedling and adult stages. Comparing of Chitinase expression profile against both pathogens has been revealed that the level of expression is increased more in resistant isoline rather than susceptible one at seedling and adult stage. The level of expression was increased 52 times relative to mock inoculation after 3 days of stripe rust inoculation at adult stage، whereas it was only 15 times more in susceptible isoline. Delay in expression of chitinase led to development of fungi mycelium in host cells of susceptible isoline.