The maize lilliputian mutation is responsible for disrupted morphogenesis and minute stature

A recessive maize mutant disrupted in seedling development was isolated following transpositional mutagenesis with Mutator. This mutant, lilliputian (lil1), exhibits a phenotype consisting of a large primary root, extremely reduced stature, crinkly leaves and has been mapped by TB-A translocations on the short arm of chromosome 2. Comparative histological analyses revealed an increase in cell number in the mutant root and leaves, as well as an irregularity in cell shapes, suggesting that the altered morphology of lil1 roots and leaves is related to an uncoordinated increase in cell divisions and to a defect in division plane alignment. On the other hand, the reduced stature of the mutant plant may be ascribed to a defect in cell elongation. In situ hybridization of primary root tissues reveals higher levels of a-tubulin transcripts in the pericycle and in cells surrounding vascular elements in mutant rather than in wild-type tissues. These features suggest a role of the Lil1 gene in the correct functioning of microtubules. Moreover, the fact that the mutation is recognizable even in the dormant embryo and that mutant seedlings are obtained from immature (12 DAP) lil1 embryos indicates that the defect in cell division pattern accounting for the disrupted seedling morphology manifests itself even during embryo development.