Skip to main content
ARS Home » Research » Publications at this Location » Publication #188706
Title: STUDY OF PHYTOALEXIN LEVELS IN RESISTANT AND SUSCEPTIBLE COTTON CULTIVARS AT INFECTION BY VERTICILLIUM DAHLIAE

Author
item ARZANOVA, I. - SIBC TASHKENT UZBEKISTAN
item VESHKUROVA, O. - SIBC TASHKENT UZBEKISTAN
item GOLUBENKO, Z. - SIBC TASHKENT UZBEKISTAN
item UZBEKOV, V. - SIBC TASHKENT UZBEKISTAN
item SALIKHOV, SH. - SIBC TASHKENT UZBEKISTAN
item STIPANOVIC, ROBERT - SIBC TASHKENT UZBEKISTAN

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2005
Publication Date: 10/30/2005
Citation: Arzanova, I.A., Veshkurova, O.N., Golubenko, Z., Uzbekov, V.V., Salikhov, S.I., Stipanovic, R.D. 2005. Study of phytoalexin levels in resistant and susceptible cotton cultivars at infection by Verticillium dahliae [abstract]. Proceedings of the 3rd Moscow International Congress on Biotechnology: State of the Art and Prospects of Development. p. 222-223.

Interpretive Summary:

Technical Abstract: Plants respond to pathogen attack by synthesizing specific compounds that are toxic to the pathogen. These compounds are called phytoalexins. Experimental evidence suggests that the speed of phytoalexin biosynthesis determines the degree of plant resistance. In theory, resistant plants will detect the pathogen quicker and begin synthesis of the phytoalexin sooner than susceptible plants. In the case of cotton, terpenoids including desoxyhemigossypol have been identified as the active phytoalexins. We have studied phytoalexins in some cotton cultivars growing in Uzbekistan which differ in resistance to infection by a virulent strain of Verticillium dahliae. For this purpose cotton seedlings of two susceptible (C-4727, AN-Bayaut) and two resistant (C-2609, Namangan-77) cultivars were stem inoculated with V. dahliae conidia (107 spores/ml). The dynamics of phytoalexins biosynthesis was studied during 96 hours. The terpenoid phytoalexins were isolated by organic solvent extraction. The total amount of terpenoid phytoalexins was determined by spectrophotometric method after reaction with phloroglucinol. The phytoalexin response was analyzed by both TLC on polyamide plates and by HPLC analysis on a Zorbax Eclipse XDB C8 column using a methanol gradient. We found that in the susceptible cotton cultivars C-4727 and AN-Bayaut phytoalexins increase only slightly during 96 hours following inoculation with V. dahliae. However, in the resistant cultivars the concentrations of phytoalexins doubled between 24 and 96 hours after inoculation. TLC and HPLC methods showed that the terpenoid phytoalexin desoxyhemigossypol (dHG) increased in the resistant cultivars. Thus, phytoalexins after pathogen infection could be an indicator of resistant in cotton cultivars during selection.