Identification Of Differentially Expressed Genes From Sugarcane-Ustilago Scitaminea Interactions By CDNA-AFLP Analysis

Sugarcane smut,caused by Ustilago scitaminea Syd.,is the most important fungal disease of sugarcane.Serious lost of stalk output and quality is observed in infected sugarcane.Sugarcane breeding resistant to smut is always an important object and one of crucial key topic in sugarcane production.Thus,smut-high-resistant sugarcane variety of NCo376 was taken as tested plant material in this study.Then,the technique of cDNA-AFLP together with the silver staining was occupied to study genes differentially expressed in the interaction system of sugarcane with the dominant race 2 of U.scitaminea.Results showed the total of 136 differentially expressed bands was obtained.40 differential bands were picked out but just 37 fragments were successfully cloned, sequenced and verified by RT-PCR analysis.Among these,31 fragments are specificly expressed (induced or inhibited)and the other 6 fragments are differentially expressed(up-regulated or down-regulated).Based on the results of blastx identification in NCBI,34 gene sequences of differentially expressed genes are likely to play important roles in sugarcane response to U.scitaminea infection.These functions involves in the biologic process of cell rescur and defense, intracellular transport,metabolosm,transcription,protein synthesis and modulation and signal transduction,etc.Among them,two differentially expressed genes get as high as 86%and 80% match to the mRNA of Zea mays,respectively,and another one gets as high as 96%match to the DNA of sugarcane chloroplast.Besides,in order to validate the function of these differentially expressed gene sequences obtained,the expression profile of three differentially expressed gene was investigated by RT-PCR.These fragments includs one induced expressed gene named SUC09 and two up-regulated expressed genes named SUC06 and SUC10.The mRNA samples isolated from sugarcane tissues infected by U.scitaminea,collected at 7 time points during 0-72 h time period after infection,were taken for RT-PCR analysis.Supported by the results of RT-PCR,the genes isolated in this study were resistance related.Under the study,the substance and technique basis for advanced sugarcane molecular breeding resistant to smut are established.And part of the shortage in the area of gene differentially expressed research in sugarcane-U.scitaminea interaction has been filled up.