Role of Melanin in Release of Extracellular Enzymes and Selection of Aggressive Isolates of Bipolaris sorokiniana in Barley

Abstract

Eighteen barley isolates of Bipolaris sorokiniana belonging to wild and clonal type of black, mixed and white subpopulations were quantitatively assayed for their melanin content and aggressiveness with respect to production of some of the extracellular enzymes such as cellulase, pectinase, amylase and protease. Cellulase and pectinase constituted major portion of the enzymes recovered from the black, mixed and white isolates. Enzyme production and aggressiveness were relatively higher in melanin devoid or low melanin isolates. The melanin deficient isolates were also differentiated from black and mixed isolates on the basis of variation in internal transcribed spacer region of the ribosomal DNA. Higher enzyme productions positively correlated with area under disease progress curve (AUDPC) and lesion development. Melanin content was negatively correlated with extracellular enzymes and aggressiveness of the isolates. Based on melanin content, lesion size, AUDPC and extracellular enzymes, the isolates were grouped in two major clusters (I and II) with further division of cluster II into two sub-clusters (II-A and II-B). The results appears to indicate a possible role of melanin in release of extracellular enzymes and hence in evolution and selection of aggressive isolates of B. sorokiniana in barley.

HIV Aspartic Peptidase Inhibitors Modulate Surface Molecules and Enzyme Activities Involved with Physiopathological Events in Fonsecaea pedrosoi

“…In the same way, the process of melanization in phytopathogenic fungi directly affects the secretion of proteins, including lytic enzymes (Henson et al, 1999). For instance, the spot blotch caused by the fungus Bipolaris sorokiniana is one of the most important diseases of wheat and barley in South Asia and, recently, a positive correlation was found between high melanin production, elevated amounts of extracellular enzymes, including peptidase, and the aggressiveness of isolates from naturally infected barley (Chand et al, 2014). …”

Effect of tricyclazole on morphology, virulence and gene expression of Aspergillus aculeatus for management of soft rot disease in peach

“…It has been reported that TCZ is associated with the absence of melanin production in the cell wall of Bipolaris sorokiniana , as well as a reduction in the production (and size) of spores (Chand et al . ). Application of TCZ reduces the virulence of pathogenic fungi B. sorokiniana (Kunova et al .…”

Extracellular protease activity and glucose production in isolates of net blotch pathogens differing in virulence

“…It was observed that the more aggressive isolates were able to produce more metabolites. For example, Chand et al (2014) previously reported that extracellular enzymes differed in wild and clonal type populations of Bipolaris sorokiniana. The cellulase production was significantly higher in wild type (11.9 U mg -1 protein) than clonal type (8.15 U mg -1 protein).…”