Title Molecular Screening of Streptomyces Isolates for Antifungal Activity and Family 19 Chitinase Enzymes
Author Youssuf Gherbawy1,2*, Hesham Elhariry1,3, Abdulla Altalhi1, Bahig El-Deeb1, and Ghada Khiralla4
Address 1Department of Biology, Faculty of Science, Taif University, P.O.Box: 888-Taif, Kingdom of Saudi Arabia (KSA), 2Permanent address: Botany Department, Faculty of Science, South Valley University, Qena, Egypt, 3Permanent address: Department of Food Science, Faculty of Agriculture, Ain Shams University, POB 68-Hadayek Shoubra, Cairo 11241, Egypt, 4Department of Biotechnology, Faculty of Science, Taif University, P.O.Box: 888-Taif, Kingdom of Saudi Arabia (KSA)
Bibliography Journal of Microbiology, 50(3),459-468, 2012,
Key Words Streptomyces, family 19 chitinase, 16S rRNA, phytopathogenic fungi
Abstract Thirty soil-isolates of Streptomyces were analyzed to determine their antagonism against plant-pathogenic fungi including Fusarium oxysporum, Pythium aristosporum, Colletotrichum gossypii, and Rhizoctonia solani. Seven isolates showed antifungal activity against one or more strain of the tested fungi. Based on the 16S rDNA sequence analysis, these isolates were identified as Streptomyces tendae (YH3), S. griseus (YH8), S. variabilis (YH21), S. endus (YH24), S. violaceusniger (YH27A), S. endus (YH27B), and S. griseus (YH27C). The identity percentages ranged from 98 to 100%. Although some isolates belonged to the same species, there were many differences in their cultural and morphological characteristics. Six isolates out of seven showed chitinase activity according to a chitinolytic activity test and on colloidal chitin agar plates. Based on the conserved regions among the family 19 chitinase genes of Streptomyces sp. two primers were used for detection of the chitinase (chiC) gene in the six isolates. A DNA fragment of 1.4 kb was observed only for the isolates YH8, YH27A, and YH27C. In conclusion, six Streptomyces strains with potential chitinolytic activity were identified from the local environment in Taif City, Saudi Arabia. Of these isolates, three belong to family 19 chitinases. To our knowledge, this is the first reported presence of a chiC gene in S. violaceusniger YH27A.