Yam Dioscorea cayennensis subsp. rotundata (Poir.) J.Miège (synonym Dioscorea rotundata Poir): Importance and expression of differential gene profiled after postharvest

Abstract

Yam (Dioscorea cayennensis subsp. rotundata (Poir) J. Miège, is an important staple food and source of carbohydrate for people in developing countries, especially West Africa. Yam production is hampered by its inability to control dormancy adequately. The goal of this study was to investigate the molecular characteristic of dormancy. A time course protein analysis and RNA fingerprinting were carried out at 0, 2, 4, 7, and 15 days by using Sodium Dodecyl Sulfate – Polyacrylamide Gel Electrophoresis (SDS-PAGE) and Amplified Fragment Length Polymorphism (AFLP), respectively. Total RNA was isolated from dormant yam tubers incubated at 32°C ± 2?C at relative humidity of 50% ± 5%. Complementary deoxyribonucleic acid (cDNA) generated from total RNA was subjected to AFLP techniques to identify differentially expressed genes up or down-regulated during dormancy. cDNA-AFLP results using different primer combinations revealed an array of transcript derived fragments (TDFs). About 14% of the TDFs were physiologically regulated either up or down or transiently induced, while 86% were expressed constitutively. Since variations in TDFs represent expression of developmentally regulated genes of interest, our results suggest that dormancy could be controlled through regulation of transcripts. This study may provide an avenue for the genetic manipulation of yam dormancy for improved varieties, and thus help to increase the number of yam generations to more than one within a year.