Abstract: Background:Telfairia occidentalis is pot-herb, cultivated extensively in Southern Nigeria. Methodology: Infection of the crop by Telfairia mosaic virus (TeMV) is characterized by severe mosaic and leaf malformation. Activities of polyphenol oxidase (PPO), peroxidase (POD), glucose-6-phosphahte dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) were evaluated spectrophotometrically using the appropriate wavelength for each of the enzymes, in two ecotypes of the vegetable infected with TeMV over a period of 120 Days After Inoculation (DAI). Results: From an apparent low level of activities at 14 and 30 DAI, there was a general increase in PPO activity in infected leaf samples of ecotype A compared to healthy controls. In ecotype B, PPO activity was highest at 14 DAI, followed by a decline and exhibited similar level of activity at later inoculation times. The POD activity was highest in ecotypes A and B at 60 and 90 DAI, respectively. For G6PDH, a rise in the activity in both ecotypes from 14-60 DAI was followed by a rather stable activity as disease progressed with percentage difference as higher as 107.3%. The activity of 6GPDH was highest at 30 DAI in both ecotypes. While the activity of the enzyme remained unchanged at later assay times in ecotype A, its activity was characterized by fluctuations in ecotype B. Values obtained for all the enzymes were significantly higher (p<0.05) in infected leaf tissues compared to their corresponding controls except for 6GPDH at later post inoculation times (60-120 DAI). Conclusion: Comparatively, the activities of all the enzymes in ecotype A, which has been found to be more susceptible to the TeMV were general higher than observed for ecotype B. It is thus suggested that the observed increases in the activity of these enzymes aided the disease severity engendered by TeMV, in the two ecotypes of T. occidentalis rather than disease mitigation as has been reported for some plant-virus combinations.
Ann Afamefuna Jerry Mofunanya, Ayodeji Timothy Owolabi and Ani Nkang, 2016. Time Course Evaluation of the Activities of Some Enzymes in Telfairia Mosaic Virus Infected Ecotypes of Telfairia occidentalis Hook f.. Plant Pathology Journal, 15: 86-94.