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Title: Tubulin perturbation leads to unexpected cell wall modifications and affects stomatal behaviour in Populus

Cortical microtubules are integral to plant morphogenesis, cell wall synthesis, and stomatal behaviour, presumably by governing cellulose microfibril orientation. Genetic manipulation of tubulins often leads to abnormal plant development, making it difficult to probe additional roles of cortical microtubules in cell wall biogenesis. Here, it is shown that expressing post-translational C-terminal modification mimics of α-tubulin altered cell wall characteristics and guard cell dynamics in transgenic Populus tremula x alba that otherwise appear normal. 35S promoter-driven transgene expression was high in leaves but unusually low in xylem, suggesting high levels of tubulin transgene expression were not tolerated in wood-forming tissues during regeneration of transformants. Cellulose, hemicellulose, and lignin contents were unaffected in transgenic wood, but expression of cell wall-modifying enzymes, and extractability of lignin-bound pectin and xylan polysaccharides were increased in developing xylem. The results suggest that pectin and xylan polysaccharides deposited early during cell wall biogenesis are more sensitive to subtle tubulin perturbation than cellulose and matrix polysaccharides deposited later. Tubulin perturbation also affected guard cell behaviour, delaying drought-induced stomatal closure as well as light-induced stomatal opening in leaves. Pectins have been shown to confer cell wall flexibility critical for reversible stomatal movement, and results presented here are consistent withmore » microtubule involvement in this process. In conclusion, taken together, the data show the value of growth-compatible tubulin perturbations for discerning microtubule functions, and add to the growing body of evidence for microtubule involvement in non-cellulosic polysaccharide assembly during cell wall biogenesis.« less
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [4] ;  [2] ;  [5] ;  [2] ;  [2] ;  [6] ;  [2] ;  [3] ;  [2] ;  [2]
  1. Univ. of Georgia, Athens, GA (United States); Washington State Univ., Prosser, WA (United States)
  2. Univ. of Georgia, Athens, GA (United States)
  3. Univ. of British Columbia, Vancouver, BC (Canada)
  4. Albert Einstein College of Medicine, Bronx, NY (United States)
  5. Taiwan Forestry Research Institute, Taipei (Taiwan)
  6. Univ. of Florida, Gainesville, FL (United States)
Publication Date:
Grant/Contract Number:
SC0008470
Type:
Accepted Manuscript
Journal Name:
Journal of Experimental Botany
Additional Journal Information:
Journal Volume: 66; Journal Issue: 20; Journal ID: ISSN 0022-0957
Publisher:
Oxford University Press
Research Org:
Univ. of Georgia, Athens, GA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; cell wall; detyrosination; guard cell; microtubule; polysaccharide; tubulin post translational modification
OSTI Identifier:
1343289