Genetic Diversity Of Venturia Inaequalis Of Shaanxi(China), UK And India With SSR Analysis

Apple scab, caused by Venturia inaequalis (Cooke) Wint., is one of the most serious apple diseases of orchards all over the world. Both leaves and fruits could be infected and caused early drops of leaves, weakness of trees and dehisce and abnormality of fruits, which made apple fruits lose their values. The occurrence and the epidemic of apple scab and the spread situation of its pathogen could be more known if it has been carried out reasearch on Venturia inaequalis. Genetic diversity of Venturia inaequalis had been tested by use of SSR analysis, and the main results are as follows:1. 21 pairs SSR special primers were tested in analyzing genetic diversity of Venturia inaequalis. 3 primers failed to get polymorphic loci, the others 18 could, and of which 6 primers succeed get a lot of polymorphic loci. These 18 primers could be used on research of Venturia inaequalis with SSR markers.2. SSR reaction system of Venturia inaequalis with those 18 primers had been set up: each 10μL amplification reaction solution was comprised 10×Buffer 1μL, MgCl2(25 mmol/L)0.7μL, dNTPs(10 mmol/L)0.16μL,primers(1μmol/L)4μL, Taq DNA polymerase(1U)0.1μL, template DNA(1 mg/L) 1μL, ddH2O 3.04μL。Amplication program was: 5 min at 94℃, then 30 cycles that consisted of 40s at 94℃, 40 s at Ta℃, 40 s at 72℃; followed by 10min extension at 72℃. The result of PCR amplification had showed that this PCR reaction system got good stability and repetition.3. Genetic diversity of 110 isolates collected from UK, India and Shaanxi province of China were tested. Results showed that isolates from Shaanxi had close corelation with that from UK, but had minor corelation with that from India; The corelation within India isoleates were very close; a few isolates may have a lot of variation which made them have a lot genetic diversity in their population; genetic diversity of isolates of Venturia inaequalis had little relation to their sources and races of their hosts. Venturia inaequalis of Shaanxi(China), UK and India may all origin from Europe.This study could help better understand the genetic diversity of Venturia inaequalis of apple and provided some basic theoretical methods on how to control apple scab disease and carry out disease- resistant breeding.