The Function Of Phosphate Starvation Response Genes OsLPR5 In The Process Of Rice Uptake And Transport Phenanthrene

The absorption of phosphorus by plants is a co-transportation,which is mainly driven by the proton gradient generated by H~+-ATPase on the plasma membrane,and the co-transportion of H~+/Pi is the main method.OsLPR5 is an ferroxidase gene in rice,which involves in the transport of phosphorus from roots to shoots.OsLPR5 plays a role in maintaining phosphorus homeostasis and development.Previous studies have found that the absorption of phenanthrene by plants is also in the form of H~+co-transportation,and the external phosphorus concentration will effect the absorption of phenanthrene by plants,which can promote the transportation of phenanthrene from roots to shoots.Polycyclic aromatic hydrocarbons(PAHs)are a common organic pollutant in environment.Plant roots absorb and accumulate from the soil media and enter human body along the food chain and food web.As a major food crop in the world,rice is the staple food for most of people in Asia.The quality and safety of rice is of great significance to human health.The study of the accumulation and translocation of polycyclic aromatic hydrocarbons in rice is of great significance to the food security.Studying the accumulation and transportation of polycyclic aromatic hydrocarbons in rice is of great significance for ensuring food security.Therefore,this study mainly uses phenanthrene as the representative(a tricyclic polycyclic aromatic hydrocarbon commonly found in soil)and OsLPR5 mutant materials as the test material to explore the role of iron oxidase OsLPR5 in regulating the absorption and transportation of phenanthrene in rice,and to explore the effects of polycyclic aromatic hydrocarbons on the growth and development and quality of rice.The main results are as follows:1.The root is the main part of rice to absorb and accumulate phenanthrene.As the concentration of external phenanthrene increases,the accumulation of phenanthrene in the shoots and roots of rice increases.Through the hydroponic experiment of different concentrations of phenanthrene to treat wild-type rice,analyze its growth and development and the concentration of phenanthrene accumulated in different parts.The results showed that phenanthrene can promote the growth of rice to a certain extent and increase the biomass of rice.The concentration of phenanthrene in the roots,shoots of wild-type rice could reach307.68 mg/kg and 13.79 mg/kg after treatment with 1.5 mg/L of phenanthrene for 8 days.This indicates that rice roots and shoots can accumulate phenanthrene.2.Phosphorus can affect the absorption and transportation of phenanthrene by rice,and low phosphate can promote the accumulation of rice roots,shoots.Through the hydroponic experiment of phenanthrene treatment(1.5mg/L)under Pi-sufficient(200μM Pi)and-deficient(-P)conditions(10μM Pi)conditions of wild type,it was found that compared with phosphate sufficiency,phosphate deficiency treatment The concentration of phenanthrene in the roots of rice plants increased by 14.73 times,and the concentration of phenanthrene in the shoots increased by 2.66 times.3.Os LPR3/5 may be involved in rice phosphorus response to phenanthrene stress.Detect the expression of phosphate-deficiency response genes Os LPR3 and OsLPR5 under different phenanthrene concentration treatments by q RT-PCR,and analyze the expression patterns of phosphate-deficiency response genes Os LPR3 and OsLPR5.The results showed that when the concentration of phenanthrene was 1mg/L and 1.5mg/L,the expression abundance of OsLPR5 in the root system was 23 and 9.8 times higher than that of the untreated root system,and the expression abundance of Os LPR3 in the root system was higher than that of the untreated root system.Increased 104 and 36.7 times.phosphate-deficiency response genes Os LPR3 and OsLPR5 in rice roots can respond to different concentrations of phenanthrene treatment,making their expression up-regulated,and their expression is strongest when the phenanthrene concentration is 1 and 1.5 mg/L.4.The ability of rice roots to control phenanthrene is inhibited,and OsLPR5 will inhibit the transport of phenanthrene to the shoots.Through the hydroponic experiment under Pi-sufficient(200μM Pi)and Pi-deficient(-P)conditions(10μM Pi)conditions under the treatment of wild-type and OsLPR5 mutant material phenanthrene(1.5mg/L),the effects of phosphorus and phenanthrene on wild-type were analyzed.And the influence of OsLPR5mutant growth and the concentration of phosphorus and phenanthrene in various parts of rice.The results are as follows:Under phosphate-deficient conditions,the concentration of phenanthrene in the roots of the OsLPR5 mutant was about 63.6%-69.0%of that of the wild type.Under low phosphate conditions,the phenanthrene transfer coefficient of the OsLPR5mutant was 84%higher than that of the wild type.Compared with the wild type,the OsLPR5mutant transported more phenanthrene to the shoots.Phenanthrene treatment will significantly inhibit the growth of rice and the OsLPR5 mutant will be more strongly inhibited.5.After phenanthrene treatment,the number of rice tillers increased and the plant height decreased.It showed that OsLPR5 can reduce the absorption of phenanthrene by rice roots and the upward translocation of phenanthrene during rice maturity,but it had no obvious effect on the accumulation of phenanthrene in rice grains and bran.Through wild-type and OsLPR5 mutant pot experiments,the effects of phenanthrene on the growth of wild-type and OsLPR5 mutants during maturity and the concentration of phosphorus and phenanthrene in various parts of rice were explored.After phenanthrene treatment,the concentration of phenanthrene in the roots of the OsLPR5 mutant decreased by 25.59%and 56.59%compared with the wild type,and the concentration of phenanthrene in the stems decreased by 37.36%and 43.96%%compared with the wild type.The absence of OsLPR5 will reduce the accumulation of phosphorus in rice culm and decrease the increase in phosphorus in leaf sheaths.In summary,The expression of OsLPR5 in roots was up-regulated by phenanthrene.Under low-phosphorus treatment,the lack of OsLPR5 at the seedling stage reduced the resistance of rice to phenanthrene,leading to the transfer of phenanthrene to the shoot;OsLPR5 at the mature stage can reduce the absorption of phenanthrene by the rice roots,reduce the transfer of phenanthrene to the shoot,and affect rice grains.And the accumulation of phenanthrene in the bran has no obvious effect.OsLPR5 is involved in the process of controlling phenanthrene by rice roots.