Genetic manipulation of key photosynthetic enzymes in the C-4 plant Flaveria bidentis

被引:78
作者
Furbank, RT
Chitty, JA
Jenkins, CLD
Taylor, WC
Trevanion, SJ
vonCaemmerer, S
Ashton, AR
机构
[1] AUSTRALIAN NATL UNIV,RES SCH BIOL SCI,COOPERAT RES CTR PLANT SCI,CANBERRA,ACT 2601,AUSTRALIA
[2] AUSTRALIAN NATL UNIV,RES SCH BIOL SCI,CANBERRA,ACT 2601,AUSTRALIA
来源
AUSTRALIAN JOURNAL OF PLANT PHYSIOLOGY | 1997年 / 24卷 / 04期
关键词
D O I
10.1071/PP97028
中图分类号
Q94 [植物学];
学科分类号
071001 ;
摘要
The NADP-malic enzyme type C-4 dicot Flaveria bidentis (L.) Kuntze was transformed with antisense and cosense gene constructs that resulted in specific decreases in single photosynthetic enzymes. The enzymes targeted were ribulose-1,5-bisphosphate carboxylase/oxygenase [EC 4.1.1.39] (Rubisco), pyruvate, Pi dikinase [EC 2.7.9.1] (PPDK) and NADP malate dehydrogenase [EC 1.1.1.82] (NADP-MDH). These enzymes were chosen as targets because they have low activity compared to photosynthetic rates (Rubisco), are subject to complex covalent regulation (NADP-MDH), or both (PPDK). T1 progeny of a number of lines of these transformants were examined for the effects of these gene constructs on enzyme levels and photosynthetic performance. Rubisco antisense transformants expressing between 15 and 100% of wild-type enzyme activity were obtained. Pyruvate, Pi dikinase antisense lines were obtained with 40-100% wild-type levels. NADP malate dehydrogenase sense constructs caused a co-suppression of enzyme activity with some lines containing less than 2% of wild-type activity. Under saturating illumination, the control coefficients for these enzymes were determined to be up to 0.7 for Rubisco, 0.2-0.3 for PPDK and effectively zero for NADP-MDH. The implications of these observations for the regulation of photosynthetic flux and metabolism in C-4 plants and the role of regulation by covalent modification are discussed.
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页码:477 / 485
页数:9
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