Piriformospora indica enhances phosphorus absorption by stimulating acid phosphatase activities and organic acid accumulation in Brassica napus

• DOI: 10.1007/s11104-018-3795-2
• Publication Date: 2018-09-08T01:05:35Z
• Authors: Meiyan Wu; Qiao Wei; Le Xu; Huizhi Li; Ralf Oelmüller; Wenying Zhang
• Keywords: 0301 basic medicine; 2. Zero hunger; 03 medical and health sciences; 15. Life on land

The root endophytic fungus Piriformospora indica (P. indica) colonizes the roots of a wide range of higher plants and promotes growth, disease resistance and stress tolerance of the hosts. We investigated the role of P. indica for phosphate (P) mobilization in soils enriched with different P sources and for P uptake into Brassicae napus (B. napus) plants. Seedlings of B. napus colonized by P. indica were cultivated in pots with sterilized-sands supplied with Ca3 (PO4)2 [Ca3-P], AlPO4 [Al-P] or FePO4 [Fe-P]. The growth of the seedlings, P content, phosphatase activities, amount of organic acids, and expression of the genes BnACP5 for a phosphatase and BnPHt1;4 for a P transporter were investigated. Piriformospora indica promotes growth of B. napus and the accumulation of P in roots and shoots when P was supplied as Ca3-P, Al-P or Fe-P in the soil. The endophyte stimulated the P availability for the plant by higher phosphatase activities and higher expression of BnACP5 in roots exposed to soil with Ca3-P, Al-P or Fe-P as main P source. The amounts of oxalic, malic and citric acids increased in rhizosphere soil with P. indica colonized by B. napus seedlings. Thus, root-colonization by P. indica promotes the accumulation of organic acids in the rhizosphere. Stronger up-regulation of BnPht1;4 in colonized vs. non-colonized roots demonstrates the involvement of the fungus in counteracting P deficiency by promoting its uptake. P. indica promotes the mobilization of P from inorganic sources and P uptake into the roots of B. napus. This is a combined effect of the stimulation of the P solubilizing phosphatase activity in the symbiotic interaction, the production of organic acids as well as the stimulation of the BnPht1;4 and BnACP5 genes under P limitation conditions.