Purification and characterization of an extracellular endo-1,4-β-xylanase from Fusarium oxysporum f. sp. melonis

Abstract

Fusarium oxysporum f. sp. melonis produces extracellular endo-1,4-beta-xylanase and beta-xylosidase when grown in shaken culture at 26 degrees C in a mineral salts medium containing oat spelt xylan and glucose as carbon sources. Endo-1,4-beta-xylanase was purified 251 times from 5-day-old culture filtrates, by Sephacryl S-200, ion exchange and gel filtration HPLC. The purified sample yielded a single band in SDS polyacrylamide gels with a molecular mass of 80 kDa on electrophoretic mobility and 83 kDa by gel filtration behavior. High activity of the endo-1,4-beta-xylanase against xylan was observed between 5 and 8 pH, and between 40 and 60 degrees C, the optimum pH and temperature being 5.0 and 50 degrees C, respectively. Kinetic properties of the enzyme are similar to those of other fungal xylanases, showing high affinity towards oat spelt xylan with a Km of 1 mM expressed as xylose equivalent.

Extracellular enzymes of Fusarium graminearum isolates

“…In general terms, the substrates utilized for inducing these enzymatic activities showed no specificity, perhaps due to the fact that they were not pure in most cases, with no clearly defined composition. Nevertheless, the combined use of this type of substrates was adequate from a qualitative and quantitatively point of view to enhance the production of plant cell wall degrading enzymes (Alconada and Martínez, 1994;1996). All the isolates of F. graminearum grew in a homogeneous and disperse filamentous form.…”

Alarming occurrence of Fusarium wilt disease in pea (Pisum sativum L.) cultivations of Jabalpur district in Central India revealed by an array of pathogenicity tests

“…Polygalacturonases produced by F. oxysporum depolymerises homogalacturan which results in effective maceration of plant tissue. F. oxysporum produces xylanolytic enzymes to depolymerise xylan which is also a major component of plant cell wall (Alconada and Martinez, 1994;Ruiz et al, 1997).…”

Two xylanase genes of the vascular wilt pathogen Fusarium oxysporum are differentially expressed during infection of tomato plants

“…The mechanisms of pathogenicity and symptom induction by this fungus are poorly understood despite many ultrastructural, biochemical, and genetic studies (Beckman 1987). The presence of xylanases in F. oxysporum has been reported (Jones et al 1972;Alconada and MartõÂ nez 1994;Christakopoulos et al 1996;Ruiz et al 1997), but their production during infection and their role in pathogenicity has not been investigated. Here we report the isolation, sequencing and expression analysis of two putative family F xylanase genes of F. oxysporum f.sp.…”