A Sheathed Spike Gene, TaWUS-like Inhibits Stem Elongation in Common Wheat by Regulating Hormone Levels
Abstract Background: The elongation and development of wheat (Triticum aestivum L.) stem play an important role in plant architecture. Shortened stem would result in sheathed spike and low yield in crops. To elucidate the molecular mechanisms underlying sheathed spike would be helpful for plant architecture and yield. Results: We found a novel gene, TaWUS-like(WUSCHEL-related homeobox like), which regulated sheathed spike and plant architecture in wheat. The plant height of overexpression transgenic lines were significantly decreased and the spike was not completely elongated and enclosed in flag leaf sheaths. Besides, the increase of tiller angle resulted in loose plant architecture and lower yield. The statistical and cytological analysis demonstrated that the length of the uppermost and secondary internode was significantly shortened, especially the uppermost internode was only half length of wild-type. The parenchyma cells obviously reduced and elongated insufficiently. The analysis of hormone content showed that there was a lack of GA3 in internodes but a higher BR content. Conclusions: TaWUS-like may inhibit the synthesis of GA and/or BR and affect the function of signal transduction of these hormones, which further caused stem shortening and plant dwarfing in wheat.