~ 427 ~ Journal of Pharmacognosy and Phytochemistry 2016; 5(4): 427-431 E-ISSN: 2278-4136 P-ISSN: 2349-8234 www.phytojournal.com JPP 2016; 5(4): 427-431 Received: 29-05-2016 Accepted: 30-06-2016 Garima Bhardwaj Department of Bioscience and Biotechnology, Banasthali University, Banasthali, Rajasthan, India Indu Ravi 1) Department of Bioscience and Biotechnology, Banasthali University, Banasthali, Rajasthan, India 2) Indira Gandhi National Open University (IGNOU), Regional Centre Jaipur, Rajasthan Arpita Sharma Department of Bioscience and Biotechnology, Banasthali University, Banasthali, Rajasthan, India Vinay Sharma Scientist, Agronomy Section, ICAR-National Dairy Research Institute, Karnal, India Nimmy MS NRC on Plant Biotechnology, IARI, PUSA Campus, New Delhi, India Corresponding Author: Indu Ravi 1) Department of Bioscience and Biotechnology, Banasthali University, Banasthali, Rajasthan, India 2) Indira Gandhi National Open University (IGNOU), Regional Centre Jaipur, Rajasthan Stimulation of polyphenol, flavonoids and phenylalanine ammonia lyase (PAL) affected by the infection of wilt disease of Cuminum cyminum caused by fusarium oxysporum Garima Bhardwaj, Indu Ravi, Arpita Sharma, Vinay Sharma and Nimmy MS Abstract Plants have developed defense mechanisms to defend themselves against most potential microbial pathogens and diseases. Phenolics (polyphenol, flavonoids) and PAL play an important role in the defense mechanism of the plants. So, this study is carried out to analyze the metabolic modifications in cumin plant after the infection with the pathogen (Fusarium oxysporum) by estimating the levels of total phenolic compounds and the activities of phenylalanine ammonia lyase (PAL) in 15 days and one month old cumin plants. The PAL proved high activity in infected plants, edifying the active phase in the synthesis of secondary metabolites in the cumin plant post-infectionally. As a consequence, in infected plants the contents of polyphenols along with flavonoid considerably exceeded in contrast to control plants. Polyphenol, flavonoid content and PAL activity were determined in two varieties viz. GC-4 (resistant) and RZ-209 (susceptible) control and pathogen (Fusarium oxysporum; Wilt) inoculated Cuminumcyminum (cumin) plants. Polyphenol and flavonoid content were higher in pathogen inoculated plants as compared to control plants with an increase till 168 h. A similar pattern of higher PAL activity was observed after pathogen inoculation with a maximum at 2 h in 15 days and one month old plants of var. GC-4 and in var. RZ-209. The results indicate a role of polyphenol, flavonoid and PAL in the defense response of Cuminum cyminum, an economically important spice of arid and semi-arid regions. The obtained results give important information concerning the plant-pathogen interactions, in the defense response for cumin improvement programs seeking the adaptation to diverse range of fungal attack along with adverse environmental factors. Keywords: Cuminum cyminum, fusarium oxysporum, defense response, polyphenols; flavonoids; phenylalanine ammonia lyase Introduction Plants responds to pathogen attack or elicitor treatments by activating a wide variety of protective mechanisms designed to prevent pathogen replication and spreading [1] . The defense mechanisms including the rapid production of reactive oxygen species [2] ; alterations in the cell wall constitution, accumulation of antimicrobial secondary metabolites known as phytoalexins [3] . Polyphenols are lipophilic in nature having more than one hydroxyl group, various studies proved that accumulation and deposition of phenols to cell wall materials and on cell walls is usually considered as an increase in resistance to fungal hydrolytic enzymes as well as a physical barrier against fungal penetration [4] . Flavonoids, a large subgroup of secondary metabolite and considered as phenolic compounds 5 (Woo et al., 2002), protect plants against various biotic and abiotic stresses and play a crucial role in the interaction between the plant and their environment [6] . Phenylalanine ammonia lyase mediates the formation of cinnamic acid from phenylalanine [7] which is a crucial branch point of primary and secondary metabolism and is the first and most important regulatory step in the formation of many phenolic acids. Cumin (Cuminum cyminum L.) is an annual plant belongs to Family Apiaceae and it is grown for production of the dry ripe fruits. Cumin is produced in the warm regions of the world, mainly in India, but it has great loss of its yield because it is mainly affected by the soil borne fungus Fusarium oxysporum f. sp. cumini, causes fusarium wilt disease in this plant. Fusarium oxysporum (Wilt causing agent) is one of the most destructive diseases of the crop and is a very common soil-borne fungus [8] . Fayzalla et al. (2009) [9] demonstrated that wilt disease caused by Fusarium oxysporum was the most important disease of soybean plants. In addition to its common use as spice in our daily life, recent studies have indicated its pharmaceutical and medicinal importance [10] .