Pi-starvation is mitigated in Medicago truncatula plants with upregulated auxin transport through auxin–strigolactone interaction

Abstract

One of the most important micronutrients required for normal development of plants is phosphorus. In terms of phosphorus starvation, plants have developed plasticity for overcoming stress, expressed in the formation of shortened and thickened cluster roots. Both phytohormones auxin and strigolactone participate in the plant response associated with the phosphate signaling. The present study revealed the interaction and correlation between auxin and strigolactones in Medicago truncatula plants with modified auxin transport under extreme conditions of phosphate deficiency and excess. In general, drastic changes in the root architecture were observed in both overexpression and RNAi-lines. In terms of phosphate deprivation the number of lateral roots has gained and the length of main root was reduced. Relative transcript level of MtLAX3 gene and the two strigolactone genes MtMAX2 and MtMAX3 was upregulated in OE/RNAi-lines and wild type plants in terms of phosphorus starvation compare to same lines in normal condition.