Efficiency of IRAP and ITS-RFLP marker systems in accessing genetic variation of Pyrenophora graminea

The usefulness of IRAP (inter-retrotransposon amplified polymorphism) and ITS-RFLP (restriction of PCR-amplified internal transcribed spacers of the rDNA) markers in the analysis of 39 Pyrenophora graminea isolates was determined. Each marker system could discriminate between all of the isolates in detecting polymorphism, albeit with variable efficiency. IRAP and ITS-RFLP produced 85% and 77% polymorphic bands, respectively, with a corresponding mean polymorphic information content (PIC) of 0.38 and 0.36. The IRAP marker index ratio (2.41) was higher than ITS-RFLP (1.50). On one hand, the quality nature of data (QND) was higher for ITS-RFLP (0.169) than IRAP (0.093). However, correlation between both marker similarity matrices was significant (r = 0.34, p < 0.05). These findings suggest their combined use in phylogenetic analysis. To our knowledge, this is the first report of a comparison involving these two advanced DNA marker systems

Xylanase Production by Fusarium Solani in Solid State Fermentation

Xylanase constitute one of the most important groups of enzymes for commercial use. In the present study, production of xylanase was enhanced using a newly isolated F. solani SyrN7 strain from infected wheat seeds via solid state fermentation (SSF) using wheat bran as substrate. Optimum pH and temperature for enzyme production were found to be 8 and 25 °C, respectively. The wheat bran to mineral solution ratios were tested. The ratio 1:3 (w/v) yielded the highest xylanase production. Among the different nitrogen sources investigated, yeast extract was the best nitrogen source and gave the highest xylanase activity (1593 U/g). The cultivation systems can easily be modified with the above tested features and enhanced the xylanase yield by 3-fold

A simple method for assessing antagonistic activity of Bacillus atrophaeus against common root rot of barley

Common root rot (CRR) caused by Cochliobolus sativus (Ito &amp; Kuribayashi) Drechs. ex Dastur is a serious disease of barley causing significant economic losses worldwide. An in vitro technique was developed for assessing directly the antagonistic potential of Bacillus atrophaeus isolate SY15b against CRR on barley. Seeds of the susceptible barely cv. WI 2291 were inoculated by mixing them thoroughly with C. sativus-SY15bsuspension and placed onto 1.5% water agar in sterile Petri dishes for 10 days. Our results demonstrated that B. atrophaeus had significant antagonistic capacities against the CRR by decreasing the percentage of barley infected area of sub-crown internodes (SCIs) as compared to controls after 10 days post incubation. Highly significant correlation coefficients (r = 0.85, P = 0.001) were found between in vitro and pot methods, indicating that in vitro co-culture testing procedure is reliable. The developed method is both simple and precise and could be used directly for a rapid assessment of the antagonistic activity of Bacillus on barley plants under uniform conditions for selecting suitable biocontrol agent against fungal soil-borne pathogens

Pospješivanje proizvodnje ksilanaze submerznim uzgojem nitaste gljive Cochliobolus sativus

The xylanase production by a new Cochliobolus sativus Cs5 strain was improved under submerged fermentation. The xylanase was induced by xylan and repressed by glucose, sucrose, maltose, xylose, starch and cellulose. Highest enzyme production (98.25 IU/mL) was recorded when wheat straw (4 % by mass per volume) was used as a carbon source after 120 h of incubation. NaNO3 increased xylanase production 5.4-fold as compared to the control. Optimum initial pH was found to be 4.5 to 5. The C. sativus Cs5 strain grown under submerged culture in a simple medium proved to be a promising microorganism for xylanase production.Submerznim uzgojem novog soja nitaste gljive Cochliobolus sativus Cs5 poboljšana je proizvodnja ksilanaze, potaknuta ksilanom, a potisnuta glukozom, saharozom, maltozom, ksilozom, škrobom i celulozom. Upotrebom pšenične slame (4 %, m/V) kao izvora ugljika, nakon 120 sati inkubacije postignuta je najveća proizvodnja enzima (98,25 IU/mL). Dodatak NaNO3 povećao je proizvodnju ksilanaze 5,4 puta u usporedbi s kontrolnim uzorkom. Optimalna početna pH-vrijednost bila je od 4,5 do 5. Utvrđeno je da se za proizvodnju ksilanaze odlično može upotrijebiti soj C. sativus Cs5, submerzno uzgojen u podlozi jednostavnog sastava

Improvement of Xylanase Production by Cochliobolus sativus in Submerged Culture

The xylanase production by a new Cochliobolus sativus Cs5 strain was improved under submerged fermentation. The xylanase was induced by xylan and repressed by glucose, sucrose, maltose, xylose, starch and cellulose. Highest enzyme production (98.25 IU/mL) was recorded when wheat straw (4 % by mass per volume) was used as a carbon source after 120 h of incubation. NaNO3 increased xylanase production 5.4-fold as compared to the control. Optimum initial pH was found to be 4.5 to 5. The C. sativus Cs5 strain grown under submerged culture in a simple medium proved to be a promising microorganism for xylanase production