CONICET | Buscador de Institutos y Recursos Humanos

Sugarcane (Saccharum spp.) is a tropical and sub-tropical, vegetative-propagated cropthat contributes to approximately 80% of the sugar and 40% of the world?s biofuelproduction. Modern sugarcane cultivars are highly polyploid and aneuploid hybridswith extremely large genomes (>10 Gigabases), that have originated from artificialcrosses between the two species, Saccharum officinarum and S. spontaneum. Thegenetic complexity and low fertility of sugarcane under natural growing conditionsmake traditional breeding improvement extremely laborious, costly and time-consuming.This, together with its vegetative propagation, which allows for stable transfer andmultiplication of transgenes, make sugarcane a good candidate for crop improvementthrough genetic engineering. Genetic transformation has the potential to improveeconomically important properties in sugarcane as well as diversify sugarcane beyondtraditional applications, such as sucrose production. Traits such as herbicide, diseaseand insect resistance, improved tolerance to cold, salt and drought and accumulationof sugar and biomass have been some of the areas of interest as far as theapplication of transgenic sugarcane is concerned. Although there have been muchinterest in developing transgenic sugarcane there are only three officially approvedvarieties for commercialization, all of them expressing insect-resistance and recentlyreleased in Brazil. Since the early 1990?s, different genetic transformation systems havebeen successfully developed in sugarcane, including electroporation, Agrobacteriumtumefaciens and biobalistics. However, genetic transformation of sugarcane is a verylaborious process, which relies heavily on intensive and sophisticated tissue cultureand plant generation procedures that must be optimized for each new genotypeto be transformed. Therefore, it remains a great technical challenge to develop anefficient transformation protocol for any sugarcane variety that has not been previouslytransformed. Additionally, once a transgenic event is obtained, molecular studiesrequired for a commercial release by regulatory authorities, which include transgeneinsertion site, number of transgenes and gene expression levels, are all hindered by the genomic complexity and the lack of a complete sequenced reference genome for thiscrop. The objective of this review is to summarize current techniques and state of the artin sugarcane transformation and provide information on existing and future sugarcaneimprovement by genetic engineering.

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