Identification and characterisation of maize micro RNA s involved in developing ears

In maize, kernel row number trait is determined during the period when spikelet pair meristems ( SPM s) give rise to spikelet meristems ( SM s). Expression levels of many genes change during this period due to regulation at transcriptional and post‐transcriptional levels. Micro RNA s (mi RNA s) act as key regulating factors of post‐transcriptional gene expression. To discover mi RNA s involved in maize ear development, S olexa deep sequencing was performed on a maize inbred line, Z ong3. Ears at the stage when SPM s produce SM s were harvested to extract RNA . Deep sequencing revealed 85 conserved mi RNA s belonging to 17 mi RNA families. mi RNA families differed greatly in their abundance, from over 160,000 to only five reads. In addition, 31 novel maize mi RNA s were identified using stringent criteria. The results show that mi RNA ‐mediated regulation of gene expression is present in developing maize ears at the stage when SPM s produce SM s; both conserved and novel mi RNA s are involved.