Induction of Phenylalanine Ammonia Lyase in The Seedlings of Cucumber and Chilli by The Elicitors is Species-and Tissue-Specific

Cucumber and chilli face huge loss of yield due to various etiologies of diseases. Hence, fungicides and pesticides are used to control diseases, which pose environmental threats. Induction of systemic acquired resistance (SAR) of plants by chemicals is an environment-friendly alternative of protecting plants against invading pathogens. SAR is characterized by synthesis of antifungal proteins, production of phytoalexins and accumulation of phenolic compounds. These phenolics compounds play a pivotal role in increasing the resistance mechanisms of plants. Thus, present investigation was planned to evaluate the activity of Phenylalanine ammonia layase (PAL) induced in response to abiotic and biotic elicitors in cucumber and chilli. We found that all the elicitors viz., copper sulphate, mercuric chloride, salicylic acid, UV light and fungal cell wall elicitors prepared from the fungal cultures of Fusarium oxysporum Schlecht and Colletotrichum gleosporioides Penz used, induced PAL activity to a significantly high-level. The response of seedlings towards elicitation was initially low, which gradually increased after 30h of elicitation and the peak activity of PAL was recorded between 45 to 60h after elicitation. The time needed for PAL activity to reach its peak depended on the species, elicitor and seedling part.