CURLED LATER1 encoding the largest subunit of the Elongator complex has a unique role in leaf development and meristem function in rice.

The Elongator complex, which is conserved in eukaryotes, has multiple roles in diverse organisms. InArabidopsis thaliana, Elongator is shown to be involved in development, hormone action and environmental responses. However, except for Arabidopsis, our knowledge of its function is poor in plants. In this study, we initially carried out a genetic analysis to characterize a rice mutant with narrow and curled leaves, termedcurled later1(cur1). Thecur1mutant displayed a heteroblastic change, whereby the mutant leaf phenotype appeared specifically at a later adult phase of vegetative development. The shoot apical meristem (SAM) was small and the leaf initiation rate was low, suggesting that the activity of the SAM seemed to be partially reduced incur1. We then revealed thatCUR1encodes a yeast ELP1-like protein, the largest subunit of Elongator. Furthermore, disruption ofOsELP3encoding the catalytic subunit of Elongator resulted in phenotypes similar to those ofcur1, including the timing of the appearance of mutant phenotypes. Thus, Elongator activity seems to be specifically required for leaf development at the late vegetative phase. Transcriptome analysis showed that genes involved in protein quality control were highly upregulated in thecur1shoot apex at the later vegetative phase, suggesting the restoration of impaired proteins probably produced by partial defects in translational control due to the loss of function of Elongator. The differences in the mutant phenotype and gene expression profile betweenCUR1and its Arabidopsis ortholog suggest that Elongator has evolved to play a unique role in rice development.