Submitted to: Journal of Nematology
Publication Type: Abstract Only
Publication Acceptance Date: 7/12/2003
Publication Date: 9/2/2003
Citation: Agudelo, P.A., Robinson, A.F., Stewart, J.M., Robbins, R.T. 2003. Histopathology of reniform nematode on Gossypium longicalyx and interspecific cotton hybrids [abstract]. Journal of Nematology. 35:322.
Technical Abstract: The histopathology of reniform nematode on roots of Gossypium longicalyx, G. hirsutum, and interspecific cotton hybrids was studied by light microscopy. Useful resistance to reniform nematode in G. hirsutum appears to be very limited, so recently there has been increased interest in the introgression of resistance to this nematode from G. longicalyx and other Gossypium species into G. hirsutum genotypes. Gossypium longicalyx is highly resistant to reniform nematode. The mechanisms for resistance, however, are not known and no observations on the cellular changes induced by the nematode in the plant have been published. In G. longicalyx roots, penetration by female nematodes was confirmed, and incipient swelling of the females, indicating initiation of maturation of the reproductive system, was observed. Maturation up to the formation of a single embryo inside the female body was frequent, but no maturation beyond this was observed. In the hybrids, diverse responses were observed among plants. Reactions ranged from highly compatible, with the formation of active syncytia and full development of females, to incompatible and no apparent development of the female. Compatible plants showed characteristic hypertrophied cells, enlarged nuclei, dense cytoplasm, and partial dissolution of cell walls, whereas incompatible plant reactions included lignification of the cells adjacent to the nematode head, or the complete collapse and necrosis of the cells involved. The need to characterize reactions and to carefully select among the hybrid plants during the introgression process, as well as the importance of combining the results of reproduction tests with histological observation of the plant-nematode interactions is discussed.