Welcome to the Plant Germplasm Preservation Research Unit

The research team at NCGRP is called the Plant Germplasm Preservation Research Unit (PGPRU). PGPRU is an integral part of the National Plant Germplasm System (NPGS) infrastructure. PGPR’s role is to support collections activities by developing strategies and technologies that:

• improve the efficiency of ex situ genebanks and
• expand the potential uses of genebanked samples

Genebanking is really an investment for the future. The investment will pay off if we can anticipate the needs of tomorrow’s ever-expanding genebank users and develop genebank strategies that satisfy those needs in an economical way. Successful genebanking requires linking a physical sample with accurate information about it, and then making sure that the stored sample retains the same properties as the material from which it originated.

Five strategies pursued within the PGPRU group aimed at improved genebanking include:

1. Maintaining biological integrity
2. Sampling representatively to accommodate current and anticipated uses and multiple conservation targets
3. Providing annotation that authenticates, calibrates and characterizes samples
4. Integrating information systems
5. Providing germplasm with validated phenotypic and genetic descriptions

Genebanked samples are used for a variety of reasons by diverse
customers:

• Genetic “improvement”
• Conservation of biodiversity
• Mechanistic studies of adaptation 
• Systematics and taxonomy 
• Environmental monitoring
• Epidemiology
• Forensics 
• New questions in new disciplines

PGPR also has provided many innovations that have been implemented to improve genebanking worldwide. 

Some current projects are described below.

The PGPR team is charged with trouble-shooting key NPGS operations to ensure cost-effective procedures today and relevance and impact of NPGS collections in the future:

1) Maintaining biological integrity

 This requires that the physical structure and chemical composition of the stored material remains unchanged through time so that future researchers can test for the presence of compounds or evaluate the appearance of plant cells and organs. Preserving biological integrity usually requires cooling, drying or applying chemical fixatives to samples – all of which can be lethal.

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2) Sampling representatively to accommodate current and anticipated uses and multiple conservation targets

Conservation targets for a genebank include particular genes, genotypes or gene frequencies. Genetic diversity embodied by these different conservation targets should be available to future users without oversampling and unnecessary duplication.

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3) Providing annotation that authenticates, calibrates and characterizes samples

Genebank users need information about where, how and when a sample was collected in order to understand why the sample is the way it is. The information must be standard to avoid misinterpretations and must have a traceable history to ensure accountability.

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4) Integrating information systems

Databases that describe holdings of repositories from all parts of the world must be interoperable to ensure that users have access to the full breadth of available material and information.

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5) Providing germplasm with validated phenotypic and genetic descriptions

Germplasm repositories differ from other genebanks or repositories in that they provide living samples that can be grown out and used further. Providing living samples introduces the risk of change through mortality during the genebanking process or through drift or selection when material is regenerated.

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Innovations

Innovations developed by the PGPR team have directly improved germplasm repository operations at NCGRP and at genebanks around the world. Innovations that are now implemented in routine operations include:

• Low temperature and moisture treatments that maximize seed longevity

• cryogenic methods to preserve diverse plant materials

   

• evaluation of containers to ensure sample performance in a variety of storage treatments

• new ways to evaluate genetic diversity within collections

• identification of core subsets of accessions that maximize genetic diversity with the minimum number of individuals

• development of database structures that allow molecular genetic data to be entered and retrieved from NPGS’s database system, GRIN (Genetic Resources Information Network).

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Current research projects build on past accomplishments with additional focus on:

• predicting response of diverse germplasm to storage conditions using non-invasive techniques

Gas Chromatography of head space volatiles.

Differential scanning calorimetry.

Temperature-controlled Dynamic mechanical analysis.

• identifying the physiological basis for differences in response to preservation stresses

• monitoring cellular responses to the cryopreservation process

• identifying genetic and environmental factors that contribute to various responses to preservation stresses

• discovering the basis of genetic bottlenecks and change in genetic composition of genebanked samples

• linking diversity measures based on phenotype with genotypic measures

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For further information about NCGRP research contact PGPR principal investigators:

Dr. Christina Walters (Lead) 
Christina.Walters@ars.usda.gov
  - Seed: development, storage, germination
  - Biophysics of cellular stabilization

Dr. Gayle Volk 
Gayle.Volk@ars.usda.gov
  - Vegetative propagules: acclimation and growth
  - Cellular responses to preservation stress

Dr. Chris Richards
Chris.Richards@ars.usda.gov
  - Population and Conservation Genetics

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