Coding And Over-expressing Of Water Channel Protein PpTIP4,l And The Effect Of Different Nitrogen Forms On Urea Absorption Of Peach

Fertilizer plays an important role in agricultural production, the chemical fertilizersaccounted for about55%of grain yield in developing countries. Urea was widely used as amainly nitrogen fertilizer because of its high nitrogen content (N46%). Urea was existed andproduced in internal and external environment of the plant, it played an important role inabsorb of external nitrogen for growth and maintain the balance and re-use of nitrogenmetabolism of plants. The existing data show that, the utilization on the seasonal absorptionof urea fertilizer in most fruit trees was only15-30%. In order to provide theoretical andtechnical support to improve the absorption and utilization of urea in fruit trees and reducenitrogen pollution, this test was studied the Coding and over-expressing of PpTIP4.1(waterchannel protein) and the effect of different nitrogen forms on urea absorption of peach.Themain results were as follows:1. According to the peach genome sequence to identify ppa010453m which washomologous of AtTIP4.1that was encoding Arabidopsis urea transporter gene, the knownpeach sequences was used to design primer for isolation of ppa010453m.Analysis revealed a750bp sequence obtained by PCR technology was the full-length of encoding region, calledPpTIP4.1.PpTIP4.1encoding a protein of249amino acids with a mass of26.2kDa.Thededuced amino acid sequence of PpTIP4.1showed78.09and74.00percent identity to theAtTIP4.1(Arabidopsis) and NtTIPa(Tobacoo) encoding gene.2. Semi-quantitative RT-PCR analysis revealed that PpTIP4.1gene expression indifferent tissues in roots and flowers of the peach, but not expressed in stems and leaves, therelative value in roots was higher than flowers.3. In order to determine the physiological and biochemical function of PpTIP4.1, aconstruct containing full-length encoding region of ppa010453m(urea transporter protein)gene in sense orientation driven by the constitutive caulifower mosaic virus35S promoter wasassembled and introduced into Arabidopsis. Determination of the absorption kinetics of thetransgenic Arabidopsis, it was founded that: In the treatment of low concentrations of urea,there were no significant differences between transgenic and wild-type Arabidopsis ofabsorbtiion before12hs, transgenic Arabidopsis absorption rate slowed down from the first 24h, and significantly lower than wild-type from the36h. In the treatment of highconcentrations of urea, the uptake of urea for transgenic Arabidopsis was higher thanwild-type Arabidopsis and was significant difference after28h.4. Transgenic Arabidopsis apparent growth show that in the same growth conditions,transgenic Arabidopsis began flowering in less than40days, while wild-type Arabidopsis justbegan flowering after50days. The flowering-stage of transgenic Arabidopsis was earlier thanwild-type Arabidopsis for about10days. Preliminary indicate that PpTIP4.1may haverelation with flowering, to promote flowering of Arabidopsis thaliana.5. The effect of different nitrogen forms on absorption and distribution of urea in peachwas studied using the15N isotope trace technique under bag-controlled released condition.The results showed that15N utilization rate was13.81%,10.92%,15.53%and15.78%respectively in four different treatments which were urea alone, urea and nitrate mixedfertilizer, urea and ammonium nitrogen mixed fertilizer, urea and ammonium nitrate mixedfertilizer with1:1:1. The utilization rate of urea and ammonium nitrogen mixed fertilizer, ureaand ammonium nitrate mixed fertilizer with1:1:1were significantly higher than othertreatments, which can improve the plant’s absorption and utilization of urea-N; The15Nutilization of Urea and nitrate mixed fertilizer was significantly lower than other treatments,which suggested to reducing the plant’s absorption and utilization of urea nitrogen. Thedistribution of15N was higher in the leaf than other organs, accounting for over60%of thetotal absorption. The rank of others was roots>trunks>branches. The total N of urea andammonium nitrogen mixed fertilizer treatment plants was the highest, but its apparent growthamount was lower than urea and nitrate mixed fertilizer treatment.