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United States Department of Agriculture

Agricultural Research Service

Research Project: Management of Temperate-Adapted Fruit, Nut, and Specialty Crop Genetic Resources and Associated Information

Location: National Clonal Germplasm Repository (Corvallis, Oregon)

Title: Melatonin enhances the recovery of cryopreserved shoot tips of American elm (Ulmus Americana L.)

Authors
item Uchendu, Esther -
item Shukla, Mukund -
item Reed, Barbara
item Saxena, Praveen -

Submitted to: Journal of Pineal Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 6, 2013
Publication Date: October 15, 2013
Citation: Uchendu, E.E., Shukla, M.R., Reed, B.M., Saxena, P.K. 2013. Melatonin enhances the recovery of cryopreserved shoot tips of American elm (Ulmus Americana L.). Journal of Pineal Research. 55:435-442. DOI:10.1111/jpi.12094.

Interpretive Summary: Climate change and the global migrations of people and goods have exposed trees to new diseases and abiotic challenges that threaten the survival of species. In vitro germplasm storage via cryopreservation is an effective tool to ensure conservation of tree species, but plant cells and tissues are exposed to multiple stresses during the cryopreservation process. The current study was designed to evaluate the potential of melatonin to improve survival through the process of cryopreservation. Shoot tips of in vitro-grown plantlets and dormant winter buds of American elm were successfully cryopreserved in liquid nitrogen at -196 °C under controlled environment conditions following melatonin treatment and cold acclimation (CA) with two protocols. Approximately 80 to 100% of shoots were able to grow using melatonin-enriched media. Shoot tips of dormant winter buds consistently produced nearly 100% re-growth with both techniques. Our results demonstrate the usefulness of the antioxidant melatonin for long-term storage of naturally resistant elm germplasm.

Technical Abstract: Climate change and the global migrations of people and goods have exposed trees to new diseases and abiotic challenges that threaten the survival of species. In vitro germplasm storage via cryopreservation is an effective tool to ensure conservation of tree species, but plant cells and tissues are exposed to multiple stresses during the cryopreservation process. The current study was designed to evaluate the potential of melatonin to improve survival through the process of cryopreservation. Shoot tips of in vitro-grown plantlets and dormant winter buds of American elm were successfully cryopreserved in liquid nitrogen at -196 °C under controlled environment conditions following melatonin treatment and cold acclimation (CA) with either vitrification or encapsulation-vitrification protocols. Explants had optimal re-growth following cryopreservation when treated with the Plant Vitrification Solution#2 (PVS2) for 10 min. Supplementation of both pre-culture and re-growth media with melatonin significantly enhanced re-growth of frozen shoots compared to the untreated control (p<0.05). Approximately 80 to 100% of shoot explants were able to grow under optimized conditions using melatonin-enriched media. Shoot tips of dormant winter buds consistently produced nearly 100% re-growth with both techniques. The main steps of the optimized protocol are 14 day cold acclimatized cultures exposed to a preculture medium with 0.1-0.5DM melatonin for 24 h, application of PVS2 for 10 min, rapid cooling in liquid nitrogen, rapid re-warming, removal of cryoprotectants, and recovery on a medium supplemented with 0.1-0.5DM melatonin. Our results demonstrate the usefulness of the antioxidant melatonin for long-term storage of naturally resistant elm germplasm.

Last Modified: 9/20/2014
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