W684 Identification and Characterization of Transcripts Associated with Tolerance to Drought and Flooding Stress in Sugarcane

Date: Sunday, January 15, 2012
Time: 9:00 AM
Room: Royal Palm Salon 1-2
John J. Riascos , Colombian Sugarcane Research Center (Cenicaņa), Cali, Colombia
Jershon Lopez-Gerena , Colombian Sugarcane Research Center (Cenicaņa), Cali, Colombia
Jorge Ignacio Victoria , Colombian Sugarcane Research Center (Cenicaņa), Cali, Colombia
Drought and flooding tolerance are desirable breeding characteristics for Colombian sugarcane cultivars due to the high cost of irrigation and drainage, which are integral part of sugarcane agriculture in the country. As a consequence we have begun the isolation and characterization of cDNAs of interest such as those from DREB (Dehydration Responsive Element Binding) and IPT (Isopentenyl Transferase) gene families, so that breeding strategies based on plant transformation can be implemented in the near future. As part of our methodology, CC 85-92 plants were maintained in a growth chamber at 28 °C, with a 13-h light (100 µEm-2 s-1) and an 11-h dark period with constant irrigation (50% soil humidity) for two months. After this time, plants were divided in four groups and subjected in an independent manner to drought, flooding (anoxia) and increased photoperiod (16-h light/8-h darkness). The fourth group was kept without any additional treatment (control). Leaves and roots were collected from plants of each treatment group and RNA was obtained. RACE-PCR and RT-PCR were used to obtain full-length cDNAs. The SUCEST and GenBank databases were used for primer design and sequence comparisons.  Among our results we have isolated six different full-length cDNAs, five with high similarity to the DREB and one to the IPT gene family. Currently we are performing Real-Time PCR in order to characterize levels of gene expression. Finally, we have recently identified tolerant and susceptible varieties to each of the characteristics of interests and cDNA libraries from transcriptome comparison are under construction.