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Pak. J. Bot., 45(1): 135-139, 2013.

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TOXICITY INDUCED BY SOLANAPYRONE A IN CHICKPEA SHOOTS AND ITS METABOLISM THROUGH GLUTATHIONE/GLUTATHIONE-S-TRANSFERASE SYSTEM

ABID RIAZ^1*, JANE NICKLIN², IRFANUL HAQUE³, CHAUDHARY ABDUR RAUF³, GHULAM QADIR³ AND FARAH NAZ³

Abstract: Solanapyrone A and C were isolated from a Pakistani isolate of Ascochyta rabiei, Pk-1. Two experiments were conducted to investigate the phytotoxic effects of the most potent toxin, solanapyrone A on chickpea cultivars and its subsequent detoxification through glutathion/glutathion-s-transferase(GST) system.  When the shoots of cultivars were fed solanapyrone A, symptoms mimicking to Ascochyta blight appeared and extent of manifestation of symptoms varied with the cultivar. In the first  experiment, the effect of  three different plant ages of  2 cultivars with different levels of resistance to toxin was determined  in terms of  GST  activity unit. GST activity in Balkasar-2000 (a resistant cultivar) increased 1.92 times, 1.72 and 1.65 times in two-week-old seedling, eight-week-old and adult plants (all treated) respectively as compared to their respective controls. In the highly susceptible cultivar, AUG-424, a slight increase (1.14 times) over control was noticed in GST activity at all the three ages. In the second experiment, where shoots of three cultivars were tested against 2 doses of the toxin, an increase in GST activity in Noor-91 (a moderately susceptible cultivar) and AUG-424 was significantly less than resistant cultivar, Balkasar-2000 showing direct relationship between resistance and activity of the enzyme. It may be concluded that it is a reason for difference in response of cultivars to the disease.

¹Research fellow, School of Biological and Chemical Sciences, Birkbeck College, University of London, UK

²School of Biological and Chemical Sciences, Birkbeck College, University of London, UK

³Department of Plant Pathology, University of Arid Agriculture, Rawalpindi, Pakistan

^*Corresponding author’s e-mail: abidriaz@uaar.edu.pk; Tel, +92 51 9290239, Fax, +92519290160