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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Research Project #434393

Research Project: Functional Genomics for Improving Nutrients and Quality in Alfalfa and Soybean

Location: Plant Science Research

2018 Annual Report

1a. Objectives (from AD-416):
The overall goal of this project is to reduce nutrient inputs, particularly nitrogen (N) and phosphorus (P), in legume crops through the identification of germplasm having root architectural diversity and the discovery of genes that may contribute to that diversity. Desired outcomes from the research proposed herein include identification of unique germplasm with altered root morphology that may reduce costly fertilizer inputs, novel genes that regulate root development and function, and fundamental insight into the biochemical processes that affect nutrient acquisition. To achieve these goals and outcomes, three integrated objectives will be pursued. Objective 1: Phenotype and evaluate root architecture changes in soybean, common bean and Medicago mutants, determine relationships between root architecture and improved nutrient acquisition, and define genome lesions. Objective 2: Evaluate whole genome transcript analysis of common bean and alfalfa through RNA-seq analysis of roots, root nodules, leaves and seeds to compare wild-type and mutants. Objective 3: Identify genes contributing to root architecture and nutrient acquisition in legumes and determine their function.

1b. Approach (from AD-416):
Identify mutant plants derived from fast neutron and Tnt1 mutagenized populations which affect root architecture and development, and define genetic lesions through next generation sequencing. Conduct RNA-seq transcript expression studies for the organs of wild type and mutant legume species such as alfalfa, common bean, and soybean to identify genes involved in unique adaptations displayed by these species. Utilize RNAi, zinc finger nuclease modification and/or antisense constructs to silence expression of selected root-specific/enhanced genes affecting root architecture and/or nutrient acquisition.

3. Progress Report:
This is a bridging project that was initiated March 2018, replacing 5062-21000-029-00D. Research is continuing utilizing the objectives of the previous project plan. In particular, progress has been made under Objective 3 to characterize alfalfa genes involved in phosphate uptake. Transgenic alfalfa plants were identified with specific mutations in each of the three genes targeted by CRISPR/Cas9 technology. Accumulation of phosphate and gene expression is currently being investigated in these plants. Additionally, new transformation constructs were developed to increase the size of gene deletions to optimize disruption of gene expression and transgenic plants have been generated.

4. Accomplishments