Abstract
Regulation of root architecture is a powerful way to adapt to limiting or excessive supplies of nutrients. When roots encounter localized source of nitrate, lateral root growth is stimulated. Studies with Arabidopsis have determined a MADS box transcription factor, ANR1, as a key regulator of this signaling pathway. In this study, we characterized AGL21 which belongs to this gene family. The lateral root length of agl21 mutant was shorter than that of wild-type plant under low-nitrate condition. By contrast, both the numbers and length of lateral roots increased by the over-expression of AGL21. In addition, transgenic plants harboring AGL21 promoter-GFP fusion gene indicated AGL21 is expressed in primary and lateral root tip under low-nitrate conditions. These results suggested that AGL21 is an essential factor to promote lateral root initiation and elongation to adapt with the changes in nitrogen environment.
