Submitted to: Plant Cell Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/17/2006
Publication Date: 10/17/2006
Citation: Jha, A.K., Dahleen, L.S., Suttle, J.C. 2006. Eythylene influences green plant regeneration from barley callus. Plant Cell Reports. 26:285-290. Interpretive Summary: Growing plant cells in tissue culture is a common method used for micropropagation or cloning of multiple plants from a single plant, and for methods used to insert new genes into plants. These systems require green plant regeneration from these cultured tissues. In barley, most of the varieties of interest do not regenerate many plants. The plant hormone ethylene was shown to affect how many plants are formed. When ethylene production was inhibited during certain times during tissue culture, the number of plants regenerated was increased. When ethylene production was increased, plant regeneration only increased in some barley varieties. Identifying the times when ethylene production needs to be reduced or increased can be used to improve green plant regeneration from specific barley varieties, making those varieties useable for experiments that require tissue culture.
Technical Abstract: The plant hormone ethylene is involved in numerous plant processes including in vitro growth and regeneration. Manipulating ethylene in vitro may be useful for increasing plant regeneration from cultured cells. As part of ongoing efforts to improve plant regeneration from barley (Hordeum vulgare L.), we investigated ethylene emanation using our improved system and investigated methods of manipulating ethylene to increase regeneration. In vitro assays of regeneration from six cultivars, involving 10 weeks of callus initiation and proliferation followed by eight weeks of plant regeneration, showed a correlation between regeneration and ethylene production: ethylene production was highest from ‘Golden Promise’, the best regenerator, and lowest from ‘Morex’ and ‘DH20’, the poorest regenerators. Increasing ethylene production by addition of 1-aminocyclopropane 1-carboxylic acid (ACC) during weeks 8-10 increased regeneration from Morex. In contrast, adding ACC to Golden Promise cultures during any of the tissue culture steps reduced regeneration, suggesting that Golden Promise may produce more ethylene than needed for maximum regeneration rates. Blocking ethylene action with silver nitrate during weeks 5-10 almost doubled regeneration from Morex and increased Golden Promise regeneration 1.5-fold. Silver nitrate treatment of Golden Promise cultures during weeks 8-14 more than doubled green plant regeneration. These results indicate that differential ethylene production is related to regeneration in the improved barley tissue culture system. Specific manipulations of ethylene were identified that can be used to increase green plant regeneration from barley cultivars. The timing of ethylene action appears to be critical for maximum regeneration.