Aluminium pre-treatment induces activation of defense responses against Fusarium infection in Triticum aestivum

Abstract

Pre-treatment with low dose of aluminium sulphate [Al₂(SO₄)₃] was assayed on wheat (Triticum aestivum L.) seedlings for its ability to induce resistance against Fusarium oxysporum infection. Pre-treatment of seven days old germinated wheat seedlings with 50 μM concentration of Al₂(SO₄)₃ reduced the severity of the disease. In Al₂(SO₄)₃ pre-treated seedlings inoculated with fungus reduction in disease severity was correlated with suppression of fungal mycelia development inside the leaf tissues. The activities of peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase were determined as resistance markers. F. oxysporum inoculation induced significant increase of all these enzymes. Such responses were expressed earlier and with much higher magnitude when Al₂(SO₄)₃ pre-treated seedlings were challenged with the pathogen. Slower disease development in Al₂(SO₄)₃ pre-treated seedlings might be due to increased deposition of total phenolic compounds and enhanced level of salicylic acid which restricts pathogen entry.