Zeamatin-Like Protein (ZLP) Gene is Associated with Resistance against A. niger in Maize (Zea mays L.)

Abstract

Maize (Zea mays L.) constitutes one of the most important crops worldwide with multi-billion dollar annual revenue. The plant is however a good substrate for growth, development and activity of filamentous fungi. A large number of fungal species causes spoilage and accumulation of mycotoxins. Plants restrict the hyphal growth by producing pathogenesis related proteins. So far 17 groups of such proteins are identified. PR-5 group comprises of the thaumatin-like proteins (TLPs), which have diverse modes of actions and act at various stages of fungal attack. Zeamatin-like protein (ZLP) is a member of TLPs, which is basically localized in seeds with enhanced expression during physiological growth and cellular differentiation. However a basal quantity is found in the leaves of many crop plants. Here we report the response of maize plant tissues against A. niger inoculation by measuring the variation in expression profile of a zeamatin-like gene. Conventional PCR coupled with RT-qPCR identifies a significant change in the expression magnitude of ZLP in pre- and post-inoculated plant samples. SDS-PAGE, followed by antimicrobial activities against A. niger, E.coli, P. aeruginosa, B. cereus, S. aureus and S. typhimurium, however, do not register a direct relationship with enhancement in gene expression. It is in line with the fact that response to pathogenesis in plants is a multigenic activity involving a series of responsible/induced genes. The assay developed is useful in primary sorting out of the maize hybrids with respect to their resistance against Aspergillus spp., especially in areas with high rate of incidence of fungal pathogenesis.