Changes in epicuticular wax, peroxidase, polyphenol oxidase and cellulase content in different mustard leaves infected with powdery mildew disease in both naturally infected and fungicide treated plants P.J.Rathod* 1 , P.M.Chatrabhuji 2 , D.N.Vakharia 1 1 Department of Biochemistry, College of Agriculture, Junagadh Agricultural University, Junagadh - 362 001, Gujarat, (INDIA) 2 Department of Chemistry, Bahauddin Science College, Junagadh - 362 001, Gujarat , (INDIA) Received: 20 th April, 2010 ; Accepted: 30 th April, 2010 Regular Paper Trade Science Inc. Volume 4 Issue 2 June 2010 BioSciences Research & Reviews in BioSciences RRBS, 4(2), 2010 [83-87] ISSN : 0974 - 7532 INTRODUCTION Pathologists reported that damage to mustard crop may be very severe (@ 17.4%) when disease appears in early stages of plant growth [2,10] . The disease is suc- cessfully controlled by synthetic chemicals, however in- discriminate uses of such chemicals have created resis- tance in pathogen and environmental pollution becomes potential threat to human and animal health. To obviate these losses it is imperative to study the host parasite interaction at the biochemical level that leads to the better understanding of the biochemical and molecular mecha- nism of disease resistance in plants and possibly to the solution of even more important task of inducing resis- tant in the susceptible plants. Enzymes secreted by host plant and pathogen play significant role in measuring susceptible and resistant nature of host plant [6,7] . Patho- gen induced cellwall degrading enzymes like cellulase, pectine methyl esterase, galacturonase are involved in rupture of host cell wall in rust disease of groundnut to make their penetration and establishment comfortable [6] . There are several biochemical changes occurs during the penetration and establishment of the pathogen on the host. Very little information is available on biochemical aspects of mustard crop in response to powdery mil- dew. All natural resistance is governed by genes and which are expressed through biochemical products such as phytoalexins, phenolics, lignins, callose formation, cellwall degrading enzymes, epicuticular wax composi- tion and pathogen related protein. Hence, efforts are being made to find out alternative, which may be safe and eco-friendly so, always need to develop a resistant ABSTRACT To examine the biochemical changes in leaves of five different cultivar with powdery mildew disease infected and treated with fungicides (hexaconezole ) results showed that It also showed greater activitity of enzyme peroxidase and polyphenol oxidase. Incase of leaves obtained from naturally infected plants at S 1 stage (no disease) recorded enzyme activity of peroxidase, polyphenol oxides and cellulase suppressed.At infectional stage of fungicide treated plants (S 2 - no disease), cultivar V 1 and V 2 showed similar results as deserved at pre infectional stage (S 1 ). However in addition to the above parameter wax content and cellulase were also higher at stage S 2 . At post infectional stage (S 3 ) controlled plants (no diseased) had higher activities of enzymes peroxidase and cellulase. Incase of diseased leaves at post infectional stage had greater amount of cellulase activity.Overall it may be concluded that mustard cultivars naturally infected with powdery mildew fungus and treated with fungicide (Hexaconezole) showed differ- ential biochemical response and enzyme activity in mustard plants.  2010 Trade Science Inc. - INDIA