ISSN 1392-3196 / e-ISSN 2335-8947
Zemdirbyste-Agriculture, vol. 105, No. 1 (2018), p. 89–94
Extracellular protease activity and glucose production in isolates of net blotch pathogens differing in virulence
Murat DİKİLİTAS, Arzu ÇELİK OĞUZ, Aziz KARAKAYA
Pyrenophora teres f. maculata (Ptm) and Pyrenophora teres f. teres (Ptt) incite net and spot forms of net blotch disease of barley, respectively. In this study, Ptm and Ptt isolates differing in virulence were compared in terms of protease activity and glucose production. Protease production by Ptm isolates ranged between 75.33 ± 4.10 and 127.33 ± 7.54 unit (U) protease activity mg-1 protein. Virulent Ptm isolates produced significantly more protease than the less virulent isolates. Similarly, glucose production by Ptm isolates ranged between 0.55 ± 0.03 and 0.84 ± 0.05 mg glucose g-1 mycelial dry weight (DW). Virulent isolates also produced significantly more glucose than the less virulent isolates. Similar results were obtained with Ptt isolates. Protease production by Ptt isolates ranged between 69.00 ± 3.79 and 123.33 ± 7.69 U protease activity mg-1 protein. Virulent Ptt isolate produced significantly more protease than the less virulent isolates. Glucose production by Ptt isolates ranged between 0.70 ± 0.03 and 0.75 ± 0.04 mg glucose g-1 mycelial DW. Differences in the glucose production of Ptt isolates were not significant. These findings corresponded to the severity of symptoms in the host tissues. It appeared that virulence mechanism in P. teres was closely associated with both protease and glucose production. The protease enzyme secreted by the fungi could be the determining factor for aggressiveness and symptom expression, and, therefore, it could be used as a marker enzyme in P. teres isolates.
Key words: glucose, net blotch, protease, Pyrenophora teres f. maculata, Pyrenophora teres f. teres, virulence.
Full text: 105_1_str12.pdf