Advertisement

Plant Cell Reports

, Volume 22, Issue 2, pp 96–104 | Cite as

Brassinolide improves embryogenic tissue initiation in conifers and rice

  • G. S. Pullman
  • Y. Zhang
  • B. H. Phan
Cell Biology and Morphogenesis

Abstract

Somatic embryogenesis (SE), the most promising technology for the large-scale production of high-value coniferous trees from advanced breeding and genetic engineering programs, is expected to play an important role in increasing productivity, sustainability, and the uniformity of future U.S. forests. To be successful for commercial use, SE technology must work with a variety of genetically diverse trees. Initiation in loblolly pine (Pinus taeda L.), our main focus species, is often recalcitrant for desirable genotypes. Initiation percentages of loblolly pine, Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco], and Norway spruce (Picea abies L., Karst.) were improved through the use of brassinolide. Brassinosteroids, which include brassinolide, are a relatively new group of natural plant growth regulators that are found in many plant species. They have been shown to have diverse, tissue-specific, and species-specific effects, including the stimulation of cell elongation and ethylene production and increasing resistance to abiotic stress. In our media, brassinolide was effective at concentrations ranging from 0.005–0.25 μM. Using control medium (no brassinolide) and brassinolide-supplemented (0.1 μM) medium, we achieved improved initiation percentages in loblolly pine, Douglas-fir, Norway spruce, and rice—15.0% to 30.1%, 16.1% to 36.3%, 34.6% to 47.4%, and 10%, respectively. Brassinolide increased the weight of loblolly pine embryogenic tissue by 66% and stimulated initiation in the more recalcitrant families of loblolly pine and Douglas-fir, thus compensating somewhat for genotypic differences in initiation. Initiation percentages in loblolly pine were improved through the combination of modified 1/2-P6 salts, 50 mg/l activated carbon (AC), adjusted levels of Cu and Zn (to compensate for adsorption by AC), 1.5% maltose, 2% myo-inositol (to raise the osmotic level, partially simulating the megagametophyte environment), 500 mg/l casamino acids, 450 mg/l glutamine, 2 mg/l α-naphthaleneacetic acid, 0.63 mg/l 6-benzylaminopurine, 0.61 mg/l kinetin, 3.4 mg/l silver nitrate, 10 μM cGMP, 0.1 μM brassinolide, and 2 g/l Gelrite. Across 12 open-pollinated families of loblolly pine, initiation percentages ranged from 2.5% to 50.7%, averaging 22.5%.

Keywords

Brassinosteroids Loblolly pine Somatic embryogenesis Initiation Pinus taeda 

Abbreviations

AC

Activated carbon

BA

6-Benzylaminopurine

8-Br-cGMP

Guanosine 3′,5′-cyclic monophosphate, 8-bromo-, sodium salt

2,4-D

2,4-Dichlorophenyloxyacetic acid

NAA

α-Naphthaleneacetic acid

Notes

Acknowledgements

We thank the member companies of IPST for financial support and Boise Cascade, Champion (now International Paper Company), Mead (now MeadWestvaco), International Paper Company, The Timber Company, Union Camp (now International Paper Company), Westvaco (now MeadWestvaco), and Weyerhaeuser Company for cones. We are grateful for the help of R. Gupta, J. Halpin, R. Howie, S. Johnson, E. Muhlberger, and K. Wong. We thank Dr. Gary Peter for discussions concerning potential auxin or cytokinin signaling compounds.

References

  1. American Forest and Paper Association (2001) http://www.afandpa.org/forestry/forestry.html
  2. Becwar MR, Pullman GS (1995) Somatic embryogenesis in loblolly pine (Pinus taeda L.). In: Mohan Jain S, Gupta PK, Newton RJ (eds) Somatic embryogenesis in woody plants, vol 3. Gymnosperms. Kluwer, Dordrecht, pp 287–301Google Scholar
  3. Bishop GJ, Kroncz C (2002) Brassinosteroids and plant steroid hormone signaling. Plant Cell [Suppl]:97–110Google Scholar
  4. Brosa D (1999) Biological effects of brassinosteroids. Crit Rev Biochem Mol Biol 34:339–358PubMedGoogle Scholar
  5. Clouse SD (2001) Brassinosteroids. In: Somerville CR, Meyerowitz EM (eds) The Arabidopsis book. American Society of Plant Biologists, Rockville, Md. http://www.aspb.org/publications/arabidopsis/
  6. Clouse SD, Sasse JM (1998) Brassinosteroids: essential regulators of plant growth and development. Annu Rev Plant Physiol Plant Mol Biol 49:427–451Google Scholar
  7. Gupta PK, Durzan DJ (1987) Biotechnology of somatic polyembryogenesis and plantlet regeneration in loblolly pine. Biotechnology 5:147–151Google Scholar
  8. Franck-Duchenne M, Wang Y, Tahar SB, Beachy RN (1998) In vitro stem elongation of sweet pepper in media containing 24-epi-brassinolide. Plant Cell Tissue Organ Cult 53:79–84CrossRefGoogle Scholar
  9. Kim S-K, Abe H, Little CHA, Pharis RP (1990) Identification of two brassinosteroids from the cambial region of Scots pine (Pinus silverstris) by gas chromatography-mass spectrometry, after detection using a dwarf rice lamina inclination bioassay. Plant Physiol 94:1709–1713Google Scholar
  10. Kyozuka J, Shimamoto K (1991) Transformation and regeneration of rice protoplasts. In: Lindsey K (ed) Plant tissue culture manual. Kluwer, Dordrecht, pp B2 1–17Google Scholar
  11. Li J, Nagpal P, Vitart V, McMorris TC, Chory J (1996) A role for brassinosteroids in light-dependent development of Arabidopsis. Science 272:398–401PubMedGoogle Scholar
  12. Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol Plant 15:473–497Google Scholar
  13. Nagmani R, Becwar MR, Wann SR (1987) Single-cell origin and development of somatic embryos in Picea abies (L.) Karst. (Norway spruce) and P. glauca (Moench) Voss (white spruce). Plant Cell Rep 6:157–159Google Scholar
  14. Pullman, GS, Gupta PK (1994) Method for reproducing conifers by somatic embryogenesis using mixed growth hormones for embryo culture. U.S. Patent No. 5294549. Issued March 15, 1994Google Scholar
  15. Pullman GS, Johnson S (2002) Somatic embryogenesis in loblolly pine (Pinus taeda L.): improving culture initiation rates. Ann For Sci 59:663–668CrossRefGoogle Scholar
  16. Pullman GS, Peter, GF (2002a) Brassinolide improves embryogenic tissue initiation in conifers (abstract). In: 10th IAPTC&B Cong. Orlando, Fla., P-1138, P 67AGoogle Scholar
  17. Pullman GS, Peter G (2002b) Methods of initiating embryogenic cultures in plants. U.S. Patent No. 6,492,174B1. Issued December 10, 2002Google Scholar
  18. Pullman GS, Webb DT (1994) An embryo staging system for comparison of zygotic and somatic embryo development. In: TAPPI R&D Div Biol Sci Symp. TAPPI Press, Atlanta, Ga., pp 31–34Google Scholar
  19. Pullman GS, Namjoshi K, Zhang Y (2003) Somatic embryogenesis in loblolly pine (Pinus taeda L.): improving culture initiation with abscisic acid, silver nitrate, and cytokinin adjustments. Plant Cell Rep (in press)Google Scholar
  20. Rajasekaran LR, Blake TJ (1998) Early growth invigoration of jack pine seedlings by natural plant growth regulators. Trees 12:420–423CrossRefGoogle Scholar
  21. Ronsch H, Adam G, Matschke J, Schachler G (1993) Influence of (22S, 23S)-homobrassinolide on rooting capacity and survival of adult Norway spruce cuttings. Tree Physiol 12:71–80Google Scholar
  22. Sasaki H (2002) Brassinolide promotes adventitious shoot regeneration from cauliflower hypocotyl segments. Plant Cell Tissue Organ Cult 71:111–116CrossRefGoogle Scholar
  23. Timmis R (1998) Bioprocessing for tree production in the forest industry: conifer somatic embryogenesis. Biotechnol Prog 14:156–166CrossRefGoogle Scholar
  24. Verhagen SA, Wann SR (1989) Norway spruce somatic embryogenesis: high-frequency initiation from light-cultured mature embryos. Plant Cell Tissue Organ Cult 16:103–111Google Scholar
  25. Wang W, Zhang X, Liu J (1992) Effects of brassinolide on somatic embryogenesis of Gossypium hirsutum. Plant Physiol Commun 28:15–18Google Scholar
  26. Yopp JH, Mandava B, Sasse JM (1981) Brassinolide, a growth-promoting steroidal lactone. I. Activity in selected auxin bioassays. Physiol Plant 53:445–452Google Scholar

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  1. 1.Institute of Paper Science and TechnologyAtlantaUSA
  2. 2.Center for Applied Genetic TechnologyThe University of GeorgiaAthensUSA

Personalised recommendations