Aims
The aims of this work were to investigate the aluminum (Al) and phosphate (P) interactions in the regulation of root system architecture of Arabidopsis thaliana seedlings and the contribution of auxin signaling in primary and lateral root growth in response to Al toxicity.
Methods
Detailed analyses of root system architecture and cell division were performed in Arabidopsis WT seedlings and in low phosphorus insensitive mutants lpi1-3 and lpr1-1 lpr2-1 in response to Al. Expression studies of P-deficiency regulated phosphate transporter AtPT2 were also conducted. The role of auxin as a mediator of root morphogenetic changes by Al was evaluated by using the auxin-signaling mutants tir1 tir1 afb2 afb3 and arf7 arf19.
Results
Al inhibited primary root growth by affecting cell cycle progression and causing differentiation of cells in the root meristem. These effects were reduced in low phosphorus insensitive lpi1-3 and low phosphate resistant lpr1-1 lpr2-1 Arabidopsis mutants. Al also activated the expression of the low phosphate-induced P transporter AtPT2 in roots. Lateral root formation by Al decreased in tir1 afb2 afb3 while arf7 arf19 mutants were highly resistant to Al in both primary root inhibition and lateral root induction.
Conclusions
Our results suggest that lateral root formation in response to Al toxicity and P deficiency may involve common signaling mechanisms while a pathway involving ARF7 and ARF19 is important for primary root growth inhibition by Al.
【非生物胁迫下TaNAM-RNAi小麦的养分分配和产量】Mary J. Guttieri Ricardo J. Stein Brian M. Waters. Nutrient partitioning and grain yield ofTaNAM-RNAi wheat under abiotic stress.Plant and Soil