ACC Oxidase and ACC Synthase Expression Profiles after Leaning of Young Radiata (P. radiata D. Don) and Maritime Pine (P. pinaster Ait.) Seedlings
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Loss of verticality in conifers affects the normal wood development by inducing changes and chemical modifications in tree stems called compression wood. It is known that ethylene influences the response during this abnormal wood-forming process. The expression pattern of genes involved in the ethylene biosynthesis pathway during gravitropic response in gymnosperms has been identified in adult trees. Young seedlings of radiata pine were inclined to reveal the expression pattern of these genes by the quantitative real-time PCR (qRT-PCR) technique. The seedlings were exposed to gravitropic stimuli and harvested after 2.5 and 10 h (early responses) of inclination, and after 24 h (late response). Sampling includes transverse cuts at three heights of the whole stem of inclined seedlings. Our data revealed that genes encoding for 1-aminocyclopropane-1-carboxylate oxidase (ACO) and 1-aminocyclopropane-1-carboxylate synthase (ACS) were differentially expressed during the time of leaning, and, interestingly, at the basal portion of radiata pine stems. Additionally, transcriptional analysis in maritime pine showed a conserved profile of gene activation in conifers, and in mature compression wood, ACO gene transcription was strongly upregulated. These results indicate that the concerted activation of genes involved in ethylene biosynthesis could be responding to leaning signals in young radiata and maritime pine seedlings.
KeywordsACC oxidase ACC synthase Ethylene biosynthesis Gravitropism Pinus radiata
This project was supported by FONDECYT (1071026), DIAT (Universidad de Talca), PBCT Anillo (ACT-41), Ecos-Conicyt (CB07-01), and postdoctoral PBCT-PSD61 projects. PR and CV thank Conicyt and Universidad de Talca, respectively, for Doctoral fellowships.
- Barker JE (1979) Growth and wood properties of Pinus radiata in relation to applied ethylene. N Z J For Sci 9:15–19Google Scholar
- Eklund L, Tiltu A (1999) Cambial activity in normal spruce Picea abies Karst (L.) and snake spruce Picea abies (L.) Karst f. virgata (Jacq.) Rehd in response to ethylene. J Exp Bot 50:1489–1493Google Scholar
- Kang BG, Burg SP (1974) Ethylene action on lateral auxin transport in tropic responses, leaf epinasty, and horizontal mutation. In: Kaigi NG (ed) Plant growth substances. Hirokowa Publishing, Tokyo, pp 1090–1094Google Scholar
- Leopold AC, Brown KM, Emerson FH (1972) Ethylene in the wood of stressed trees. HortScience 7:175Google Scholar
- Little CHA, Eklund L (1999) Ethylene in relation to compression formation in Abies balsamea shoots. Trees 13:173–177Google Scholar
- Little CHA, Pharis RP (1995) Hormonal control of radial and longitudinal growth in the tree stem. In: Gartner BL (ed) Plant stems: physiology and functional morphology. Academic Press, San Diego, pp 281–319Google Scholar
- Sundberg B, Tuominen H, Little C (1994) Effects of the indole-3-acetic acid (IAA) transport inhibitors N-1-naphthylphthalamic acid and morphactin on endogenous IAA dynamics in relation to compression wood formation in 1-year-old Pinus sylvestris (L.) shoots. Plant Physiol 106:469–476PubMedGoogle Scholar
- Timell TE (1986) Compression wood in gymnosperms, Vol 2. Heidelberg, Springer-Verlag, pp 983–1262Google Scholar
- Wang KLC, Li H, Ecker JR (2002) Ethylene biosynthesis and signaling networks. Plant Cell 14:131–151Google Scholar