Publications B. Crump HomepageHPL Homepage

Breaking barriers in SAV restoration: using plant-associated bacteria to enhance restoration success (NOAA)
P.I.s: Byron C. Crump, Evamaria W. Koch

A global effort is underway to restore coastal and estuarine ecosystems. A major part of this effort is the re-establishment of submerged aquatic vegetation (SAV) beds, the restoration of which has unfortunately met with limited success. Germination of eelgrass seeds spread for restoration purposes are often as low as 10%. Although a portion of these may be consumed or buried, it is possible that the absence of appropriate bacteria and bacterial products (e.g., plant hormones) in the newly-restored sediment may further reduce germination rates. Additionally, SAV planted in sterile sediment, such as those propagated under controlled conditions, may have their growth rates enhanced when exposed to the right combination of microorganisms. This approach is widely applied in terrestrial crops and some terrestrial plant restoration efforts.

We hypothesize that SAV, like most terrestrial plants, form a mutualistic and potentially symbiotic relationship with bacteria or fungi. Furthermore, we propose that re-introducing these naturally-occurring symbionts as a form of probiotic treatment during laboratory/field propagation and field transplantation of SAV would greatly improve restoration success. Probiotics are defined as live microorganisms which, when administered in adequate amounts, confer a health benefit on the host (FAO/WHO_report 2001). Development of this innovative probiotic technology for SAV is hindered by our limited understanding of SAV-associated microorganisms and symbiotic relationships.

We are characterizing the microorganisms attached to the leaves and roots of field-collected and laboratory-reared eelgrass (Zostera marina), wild celery (Vallisneria americana), sago pondweed (Stuckenia pectinata, former Potamogeton pectinatus), and redhead grass (Potamogeton perfoliatus). In phase 1 of this study we are using state-of-the-art molecular and cultivation techniques to discover microorganisms common to SAV, characterize potential symbionts, and cultivate candidates to use for probiotic technology development. In phase 2 we will develop and test probiotic treatments in laboratory and field settings to enhance the supply of SAV propagules for restoration in Chesapeake Bay, and to increase the success of planting SAV directly from seeds and vegetative propagules.

Project objectives:

  1. Overall objective: Develop probiotic treatments that use naturally-occurring, plant-growth-promoting microorganisms to enhance the success of SAV restoration.
  2. Identify & cultivate candidate plant-growth-promoting microorganisms associated with leaf and root surfaces of 4 Chesapeake Bay SAV species.
  3. Evaluate positive effects of these naturally-occurring microorganisms by re-introducing them prior to planting or propagation of SAV.