Mycorrhizal influence on protein and lipid of durum wheat grown at different soil phosphorus levels

Root colonization by arbuscular mycorrhizal fungi (AMF) may affect protein and lipid composition of plants by altering P nutrition or by eliciting oth er metabolic responses in the host plant. This study was conducted to deter mine the effects of an AMF and soil P on seed protein and lipid contents an d yield of two genotypes of durum wheat (Triticum durum L.). Plants were gr own in a greenhouse using soil: sand mixes with different levels of P, and with or without the AMF Glomus mosseae [(Nicol. and Gerd.) Gerd. and Trappe ]. Percentage AMF root colonization decreased as P added to soil increased. The wheat genotype CR057 had higher AMF root colonization but lower seed P and protein concentrations than CR006. Without added soil P, protein conce ntration was significantly lower and lipid concentration and seed dry weigh t higher in arbuscular mycorrhizal (AM) than in nonAM plants. Seed lipid an d protein contents were highly correlated with P content of plants. In nonA M plants, seed lipid and protein contents were low with no added soil P and did not differ with added soil P. Seed protein/lipid (Pro/L) concentration ratios of AM plants were higher than those of nonAM plants only when no P was added to the soil. The data indicate different patterns of seed P accum ulation and different relationships between seed P and protein and lipid in AM and nonAM plants. Thus, both the presence and degree of AMF root coloni zation affected seed lipid metabolism in these durum wheat genotypes.