Planta

, Volume 190, Issue 1, pp 88–96

Influence of the tobacco mosaic virus 30-kDa movement protein on carbon metabolism and photosynthate partitioning in transgenic tobacco plants

  • William J. Lucas
  • Amnon Olesinski
  • Richard J. Hull
  • James S. Haudenshicld
  • C. Michael Deom
  • Roger N. Beachy
  • Shmuel Wolf
Article

DOI: 10.1007/BF00195679

Cite this article as:
Lucas, W.J., Olesinski, A., Hull, R.J. et al. Planta (1993) 190: 88. doi:10.1007/BF00195679

Abstract

Transgenic tobacco (Nicotiana tabacum L.) plants expressing the 30-kDa movement protein of tobacco mosaic virus (TMV-MP) were employed to investigate the influence of a localized change in mesophyll-bundle sheath plasmodesmal size exclusion limit on photosynthetic performance and on carbon metabolism and allocation. Under conditions of saturating irradiance, tobacco plants expressing the TMV-MP were found to have higher photosynthetic CO2-response curves compared with vector control plants. However, this difference was significant only in the presence of elevated CO2 levels. Photosynthetic measurements made in the green-house, under endogenous growth conditions, revealed that there was little difference between TMV-MP-expressing and control tobacco plants. However, analysis of carbon metabolites within source leaves where a TMV-MP-induced increase in plasmodesmal size exclusion limit had recently taken place established that the levels of sucrose, glucose, fructose and starch were considerably elevated above those present in equivalent control leaves. Although expression of the TMV-MP did not alter total plant biomass, it reduced carbon allocation to the lower region of the stem and roots. This difference in biomass distribution was clearly evident in the lower root-to-shoot ratios for the TMV-MP transgenic plants. Microinjection (dye-coupling) studies established that the TMV-MP-associated reduction in photosynthate delivery (allocation) to the roots was not due to a direct effect on root cortical plasmodesmata. Rather, this change appeared to result from an alteration in phloem transport from young source leaves in which the TMV-MP had yet to exert its influence over plasmodesmal size exclusion limits. These results are discussed in terms of the rate-limiting steps involved in sucrose movement into the phloem.

Key words

Carbon allocation Movement protein Nicotiana Photosynthesis Plasmodesma Tobacco mosaic virus Transgenic tobacco 

Abbreviations

PFD

photon flux density

SEL

size exclusion limit

TMV-MP

tobacco mosaic virus movement protein

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • William J. Lucas
    • 1
  • Amnon Olesinski
    • 2
  • Richard J. Hull
    • 1
  • James S. Haudenshicld
    • 1
  • C. Michael Deom
    • 3
  • Roger N. Beachy
    • 4
  • Shmuel Wolf
    • 2
  1. 1.Section of Botany, Division of Biological ScienceUniversity of CaliforniaDavisUSA
  2. 2.Department of Vegetable CropsFaculty of Agriculture, Hebrew University of JerusalemRehovotIsrael
  3. 3.Department of Plant PathologyUniversity of GeorgiaAthensUSA
  4. 4.Department of Cell BiologyThe Scripps Research InstituteLa JollaUSA
  5. 5.Plant Sciences DepartmentUniversity of Rhode IslandKingstonUSA