Abstract/Summary

Aims The aims of this work were to investigate phosphate starvation responses of Brassica napus (B. napus) under heterogeneous phosphate (Pi) supply and the regulatory role of jasmonic acid (JA) in the systemic response to Pi starvation. Methods A split-root system with two separated compartments was employed to mimic heterogeneous Pi distribution in the soil and to examine the effect of heterogeneous Pi supply, and JA or DIECA (JA biosynthesis inhibitor) on growth, root morphology, Pi concentration, Acid phosphatase (APase) activity, nutrition uptake, JA concentration and expression of Pi starvation systemically-induced (PSSI) genes of B. napus. Results Heterogeneous Pi supply systemically modified root morphology that increased the total root surface area (TRSA), total root volume (TRV), total root length (TRL) and total lateral root number (TLRN) of root with local Pi supply (R+) and decreased them of root with local no Pi supply (R-) when compared to root with homogeneous Pi supply (R++) and root devoid of Pi (R--), respectively. Anthocyanin, APase activity and JA concentration in shoot and root of B. napus were systemically regulated by heterogeneous Pi supply. In addition, heterogeneous Pi supply significantly promoted nutrient uptake when compared with homogeneous no Pi supply. Root morphology of B. napus was significantly changed by exogenous addition of JA or DIECA in a split-root system. JA enhanced Pi starvation response by inducing expression of PSSI genes in shoots and roots. Conclusions Our results suggest that JA enhances systemic Pi starvation response of B. napus by regulating root morphology, Pi homeostasis and inducing expression of PSSI genes under heterogeneous Pi supply.