Phenotypic Analysis of Medicago truncatula NPF1.7 Over-Expressing Plants Grown under Different Nitrate Conditions
Description: Plants have many nitrate transporters; in the model legume Medicago truncatula, MtNPF1.7 is among them. MtNPF1.7 is important for M. truncatula growth and it has been established that MtNPF1.7 is a high affinity nitrate transporter. M. truncatula plants with mutations in MtNPF1.7 gene show defects during plants growth, with striking abnormalities in nodule development and root architecture. Nitrogen fixation is an energy expensive process; when legumes have sufficient bioavailable nitrogen like nitrate available, it suppresses nodulation and nitrogen fixation. Previous preliminary results in our lab showed that plants constitutively expressing MtNPF1.7 have a growth phenotype in the absence of nitrate, but no data was available on how M. truncatula plants constitutively expressing MtNPF1.7 are affected by the presence of nitrate. For my research, I confirmed the preliminary results on the growth of M. truncatula plants overexpressing NPF1.7 and examined these plants' phenotypes when nitrate was not provided in the growth media and when it was provided at two different concentrations. Compared with wild type A17, plants constitutively expressing MtNPF1.7 gene grow larger, have more lateral roots and more nodules when grown in the absence of nitrate and when 0.2 mM KNO3 was provided. At 1 mM KNO3, there are fewer differences between wild type A17 and plants constitutively expressing the MtNPF1.7 gene. Compared with wild type A17, plants constitutively expressing the MtNPF1.7 gene flower earlier, which indicates MtNPF1.7 gene may have a function in plant flowering.
Date: December 2017
Creator: Cai, Jingya
Partner: UNT Libraries