Gene Discovery and Expression Analysis in Sugarcane – the Story so Far

Knowledge about gene expression during sugarcane growth and maturation is limited. A gene discovery programme has been in progress at SASEX since 1994 to identify and analyse genes that are expressed in different sugarcane tissue types and developmental stages. A database of sugarcane gene sequences has been established through the generation of Expressed Sequence Tags (ESTs). This database, containing approximately 1400 sequences from leaf and culm tissues of varying maturity, has facilitated access to a myriad of genes not previously available for sugarcane research. Submission of a proportion of the sugarcane gene sequences to the dbEST international database represented the first sugarcane ESTs released into the public domain. ESTs have been identified and the expression patterns of sugarcane genes examined in maturing internodal tissue to identify genes that may be preferentially associated with culm maturation. Differentially expressed genes detected in the culm included those associated with general cellular metabolism, cell wall synthesis, carbohydrate metabolism, regulatory processes and stress responses. The results indicate that growth and maturation of the sugarcane culm is associated with the expression of genes for a wide variety of metabolic processes. Only one gene known to be involved with sucrose metabolism was detected, suggesting that genes encoding enzymes directly associated with sucrose accumulation may not be abundantly expressed in the culm. This paper reviews the major outcomes of research at SASEX towards the molecular analysis of sugarcane metabolism during growth and maturation.