Biological and Molecular Variability of Rice Sheath Rot Pathogen Sarocladium oryzae using SCAR and SRAP Markers

Abstract

Rice sheath rot disease caused by Sarocladium oryzae is a seedborne disease and is a major production constraint in some ricegrowing countries. This study aimed to evaluate some of our local riceentries to sheath rot infection with different isolates, elucidate theirphytotoxicity effect and the molecular variability among someselected isolates derived from different locations. Data revealed thatSakha 101 was the most resistant cultivar against sheath rot. TheToxin of S. oryzae completely inhibited differentiation of rice rootsand negatively affected seed germination of rice and weeds. S. oryzaeisolates showed morphological variability and polymorphism in DNA,high levels of genetic variability among isolates were identified.Using MR specific primers revealed that the two bands (1500 and1400bp) were found only in low virulent isolates. Using SRAPdendogram supported the similarity of data. Moreover, using SCARand SRAP primers could be able to differentiate among S. oryzaeisolates collected from different locations or varieties and differed intheir virulence and classified in two main clusters as high and lowvirulent. Thus, the molecular variability of S. oryzae isolates may bean important consideration in breeding programs to develop resistancefor sheath rot disease.