Arbuscular mycorrhizal fungi and endophytic fungi differentially modulate polyamines or proline of peach in response to soil flooding

Symbiotic fungi are involved in plant flooding tolerance,while the underlying mechanism is not yet known.Since polyamines(PAs)and proline are also associated with stress tolerance,it is hypothesized that the enhancement of stress resistance by symbiotic fungi is associated with changes in PAs and/or proline.The aim of this study was to analyze the effect of inoculation with Funneliformis mosseae and Serendipita indica on plant growth,PAs,and proline and the metabolisms in peach(Prunus persica)under flooding.Two-week flooding did not affect root colonization frequence of F.mosseae,while it promoted root colonization frequence of S.indica.Under flooding,plants inoculated with F.mosseae and S.indica maintained relatively higher growth rates than uninoculated plants.Funneliformis mosseae promoted root ornithine(Orn)contentration and arginine(Arg)and Orn decarboxylase activities under flooding,which promoted putrescine(Put),cadaverine(Cad),and spermidine(Spd)contentrations.Conversely,S.indica decreased contentrations of Arg,Orn,and agmatine and Arg decarboxylase activities,thus decreasing PA contentrations under flooding.Polyamines were negatively correlated with the expression of PA uptake transporter genes,PpPUT1 and PpPUT2,in peach.Polyamine transporter genes of F.mosseae(FmTPO)and S.indica(SiTPO)were regulated by flooding,of which FmTPO1 was positively correlated with Put,Cad,and Spd,along with positive correlations of Spd with SiTPO1,SiTPO2,and SiTPO4.Under flooding,F.mosseae decreased proline concentration,while S.indica increased proline concentration and correlated with expression of a△^(1)-pyrroline-5-carboxylate synthetase gene,PpP5CS2.It was thus concluded that F.mosseae modulated polyamine accumulation,while S.indica induced proline accumulation to tolerate flooding.

Arbuscular mycorrhizal fungi enhance the growth of the exotic species Ambrosia artemisiifolia

Arbuscular mycorrhizal fungi(AMF)can increase host plant nutrient uptake via their mycelium,thus promoting plant growth.AMF have always been associated with successful invasion of most exotic plant species.However,knowledge regarding how AMF affect the success of plant invasion remains limited.Exotic Ambrosia artemisiifolia is an invasive and mycorrhizal plant species.A long-term field experiment was conducted to examine the differences in AMF diversity and composition in the roots of A.artemisiifolia and Setaria viridis subjected to interspecific competition during growth.A greenhouse experiment was also performed to test the effect of Funneliformis mosseae on the growth of these two species.Ambrosia artemisiifolia invasion caused AMF diversity to change in native S.viridis roots.Meanwhile,the relative abundance of F.mosseae was significantly higher in the roots of A.artemisiifolia than in those of S.viridis.The higher AMF colonization rate in the exotic species(A.artemisiifolia)than in the native species(S.viridis)was found in both the field and greenhouse experiments.The greenhouse experiment possibly provided that AMF advantaged to the growth of A.artemisiifolia,by influencing its photosynthetic capacity as well as its phosphorus and potassium absorption.These observations highlight the important relationship of AMF with the successful invasion of A.artemisiifolia.