Mr. Carlos A. Avila, University of Arkansas, 123 Plant Science Bld, Fayetteville, AR 72701, Dr. James McD Stewart, Department of Crop, Soil, and Environmental Sciences, University of Arkansas, PTSC 115, University of Arkansas, Fayetteville, AR 72701, and Mr. Robert T. Robbins, Plant Pathology, University of Arkansas, 217 Plant Science Bld, Fayetteville, AR 72701.
The reniform nematode (RN), Rotylenchulus reniformis, represents a serious threat to cotton production. Resistance is found in diploid G. arboreum, but little is known about the resistance mechanism. In this study, we attempted to transfer resistance into upland cotton and to describe the cotton root responses to infection. The transfer of resistance into upland cotton has been accomplished by crossing G. arboreum (A2-194) with G. trilobum to produce an interspecific hybrid and doubling the chromosome number with colchicine. The resulting allotetraploid was backcrossed with DP491. Plants from the BC2F1 and the BC2F2 showed resistance to the RN. G. arboreum response to infection was evaluated through cDNA-AFLP analysis 16-days after inoculation using a resistant and susceptible accession. Cellular transport, cell cycle, and DNA processing had more transcripts in the susceptible accession than in the resistant one. We hypothesize that the transcripts associated with those processes may be related to syncytia formation. Opposite, processes that may be involved in resistance mechanisms, such as cellular rescue, defense and transcription, had more transcripts in the resistant accession.
