Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/26/2008
Publication Date: 6/22/2008
Citation: Shen, J., Cheng, L., Liu, J., Zhang, F., Allan, D.L., Culler, A., Cohen, J., Vance, C.P. 2008. Auxin mediates patterning of cluster root development induced by phosphorus deficiency in Lupinus albus [abstract]. American Society of Plant Biologists Annual Meeting, Pan American Congress on Plants and BioEnergy, June 22-25, 2008, Merida, Mexico. Abstract No. P33009. Available: http://abstracts.aspb.org/pb2008/public/P33/P33009.html. Interpretive Summary:
Technical Abstract: White lupin (Lupinus albus L.) develops cluster roots under phosphorus (P) deficiency. This species is widely used as a model system to study the morphology and physiology of cluster roots. However, the mechanism of P deficiency-induced cluster root formation is not fully understood. To evaluate the contributions of auxin to cluster root formation, we examined the gradient of IAA concentration, expression of IAA reporter DR5-GUS, and expression of LaIAA14 and auxin influx at five different developing stages of cluster root formation including root tips, meristem initiation, initiated but not emerged, juvenile and mature cluster roots. Phosphorus deficiency significantly increased the IAA concentrations in all cluster root segments except for root tips. Higher IAA concentrations were found in root segments at initiation and juvenile cluster root stages under P deficiency, but there was no significant difference in IAA concentrations in root segments receiving normal P supply. The number of emerged rootlets or meristems before emergence in the P-deficiency plants was significantly greater than in the P-adequate plants. LaIAA14 was highly expressed at all stages of cluster root formation except for juvenile stage. Phosphorus deficiency enhanced the expression of LaIAA14 regardless of root developmental stages. In contrast, the high expression of auxin influx was concentrated in root tips and meristem initiation, but not in the emerging cluster roots, indicating an early signal sensing. Compared with cluster roots, normal roots exhibited a relatively high expression for auxin influx. The results reflect auxin involvement in cluster root development induced by P deficiency in Lupinus albus.