Induction of chitinase in response to Aspergillus infection in sorghum (Sorghum bicolor (L) Moench)

Abstract

Chitinase is an antifungal protein which is induced in higher plants during infection and stress. In this paper the induction of chitinase activity in response to infection by Aspergillus parasiticus (NRRL 2999) in six sorghum (Sorghum bicolor (L) Moench) genotypes and its association with aflatoxin production were investigated. Chitinase was induced in all six genotypes (two each of red, yellow and white sorghum) when infected by A parasiticus (NRRL 2999). The induction of chitinase activity was highest in the white cultivars, followed by the yellow and red genotypes, compared with healthy grains. In the white cultivars the chitinase activity increased on the 6th and 9th days after infection and was fourto fivefold higher than in healthy grains. The total aflatoxin produced was lower in the red genotypes than in the yellow and white genotypes. The white genotypes showed maximum total aflatoxin production at 6 days after infection. The aflatoxins produced in the white genotypes were comparable to those in the red genotypes. There was a significant positive correlation between chitinase activity and aflatoxin production in red sorghum (r 2 = 0.600, p ≤ 0.001) and white sorghum (r 2 = 0.411, p ≤ 0.001). Maximum chitinase activity was observed on day 12 in all genotypes under healthy conditions.

Inhibitory effect of phenolics extracted from sorghum genotypes on Aspergillus parasiticus (NRRL 2999) growth and aflatoxin production

“…Even though the yellow and white genotypes contained low levels of polyphenols, they showed an inhibitory action on aflatoxin production, which may be attributed to the presence of phenolics as well as other factors such as antifungal proteins, including chitinases, 19 β-glucanases and ribosome-inactivating proteins.…”

The Sorghum Grain Mold Disease Complex: Pathogens, Host Responses, and the Bioactive Metabolites at Play

“…Under Aspergillus infection, sorghum has been shown to produce varying levels of antifungal proteins including sormatin, glucanases, and chitinases (Seetharaman et al, 1997;Ratnavathi and Sashidhar, 2004). Ratnavathi and Sashidhar (2004) showed chitinase as a response mechanism to Aspergillus from relatively strong positive correlations between chitinase activity and aflatoxin levels for both white-pericarp (r 2 = 0.482) and redpericarp (r 2 = 0.600) sorghums. The authors added that the lower rate of chitinase activity in red to white-seeded sorghums is likely due to red-seeded sorghums reliance on a constitutively higher presence of polyphenols.…”

Genome-Wide Identification and Expression Analysis of Chitinase Genes in Watermelon under Abiotic Stimuli and Fusarium oxysporum Infection

“…However, the chitinases occur widely in higher plants, including monocots and dicots, which do not contain chitin. To date, chitinases have been found in the Arabidopsis thaliana (hereafter Arabidopsis ) and rice [ 13 ], maize [ 14 ], sorghum [ 15 ], soybean [ 16 ], black bean [ 17 ], barley [ 18 ], cabbage [ 19 ], banana [ 20 ], cucumber [ 6 ], garlic [ 21 ], tea [ 22 ], muskmelon [ 23 ], tomato [ 24 ], mulberry [ 25 ] and wheat [ 26 ]. Chitinases are considered to belong to the category of pathogenesis-related (PR) proteins.…”