Decrease in phosphoribulokinase activity by antisense RNA in transgenic tobacco:relationship between photosynthesis, growth, and allocation at different nitrogen levels

Banks, Fiona M. and Driscoll, Simon P. and Parry, Martin A J and Lawlor, David W. and Knight, Jacqui S. and Gray, John C. and Paul, Matthew J. (1999) Decrease in phosphoribulokinase activity by antisense RNA in transgenic tobacco:relationship between photosynthesis, growth, and allocation at different nitrogen levels. Plant Physiology, 119 (3). pp. 1125-1136. ISSN 0032-0889

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Abstract

To study the direct effects of photosynthesis on allocation of biomass by altering photosynthesis without altering leaf N or nitrate content, phosphoribulokinase (PRK) activity was decreased in transgenic tobacco (Nicotiana tabacum L.) with an inverted tobacco PRK cDNA and plants were grown at different N levels (0.4 and 5 mM NH 4NO 3). The activation state of PRK increased as the amount of enzyme was decreased genetically at both levels of N. At high N a 94% decrease in PRK activity had only a small effect (20%) on photosynthesis and growth. At low N a 94% decrease in PRK activity had a greater effect on leaf photosynthesis (decreased by up to 50%) and whole-plant photosynthesis (decreased by up to 35%) than at high N. These plants were up to 35% smaller than plants with higher PRK activities because they had less structural dry matter and less starch, which was decreased by 3- to 4-fold, but still accumulated to 24% to 31% of dry weight; young leaves contained more starch than older leaves in older plants. Leaves had a higher ion and water content, and specific leaf area was higher, but allocation between shoot and root was unaltered. In conclusion, low N in addition to a 94% decrease in PRK by antisense reduces the activity of PRK sufficient to diminish photosynthesis, which limits biomass production under conditions normally considered sink limited.

Item Type:
Journal Article
Journal or Publication Title:
Plant Physiology
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1300/1314
Subjects:
ID Code:
76030
Deposited By:
Deposited On:
21 Oct 2015 05:03
Refereed?:
Yes
Published?:
Published
Last Modified:
19 Aug 2020 02:40