FLOWERING-RELATED GENES ARE NOT INVOLVED IN THE DEVELOPMENT OF SMUT WHIP

SUGARCANE GROWS repeating vegetative units that make up the stalk. Each unit consists of three structures, a leaf, a node and an internode, which arise from the apical meristem that systematically switches between each morphology. The production of vegetative units ceases once the apical meristem changes to reproductive growth. The vegetative growth of the apical meristem also stops when it is infected with smut fungus (Sporisorium scitamineum). Following this, a whip is produced which is covered with spores that disperse and cause further infection. The whip is similar in appearance to the central branch or rachis of a sugarcane inflorescence. It has been suggested that the whip is a modified floral structure. In order to produce flowers, a sugarcane plant must be sufficiently mature, with at least 2–4 fully expanded internodes, before any floral induction signal will result in the development of a flower. In contrast, a whip can be produced in a very young plant without expanded internodes. The possibility that the developmental pathways for flower and whip production are similar could provide an avenue for flowering to be induced in younger plants. Such a technology would assist breeders to transfer new traits more rapidly through multiple generations per year. This paper presents results from an experiment comparing expressions of genes involved in flowering between S. scitamineum infected and non-infected sugarcane. The study found that the expression of 14 flowering-related genes was not the same at the time of whip development and flowering.