Arabidopsis seedling growth, storage lipid mobilization, and photosynthetic gene expression are regulated by carbon:nitrogen availability
Arabidopsis seedling growth, storage lipid mobilization, and photosynthetic gene expression are regulated by carbon:nitrogen availability
复制标题
DOI：
10.1104/pp.010475
复制
发表时间：
2002-02-01
期刊：
影响因子：
7.4
通讯作者：
Graham, IA
中科院分区：
文献类型：
--
作者：
Martin, T;Oswald, O;Graham, IA
本工作的目的是确定碳和氮的有效性对拟南芥幼苗生长发育的影响在多大程度上是由于这些营养物质单独或共同作用所致。幼苗在低氮(0.1 mm)条件下生长，幼苗和子叶大小、鲜重、叶绿素和花青素含量显著降低，但内源糖含量略有增加。在氮素耗尽的生长基质中添加100 mM蔗糖(Suc)，子叶大小和叶绿素含量进一步减小，花青素和内源糖含量总体增加。在低氮和100 mM蔗糖上生长的幼苗几乎完全阻止了贮藏脂肪的分解，而在低氮和高蔗糖上生长的幼苗显著地抑制了贮藏脂肪的分解。只有在低氮条件下才能观察到碳水化合物对光合作用基因表达的抑制。低氮(0.1 mM)，在没有外源碳水化合物的情况下，导致叶绿素a/b结合蛋白和核酮糖二磷酸羧化酶小亚基基因转录水平的显著下降。因此，碳氮比而不是碳水化合物状态似乎在调节幼苗生长的各个方面起着主导作用，包括储藏动员和光合作用基因表达。
The objective of the current work was to establish the degree to which the effects of carbon and nitrogen availability on Arabidopsis seedling growth and development are due to these nutrients acting independently or together. Growth of seedlings on low (0.1 mm) nitrogen results in a significant reduction of seedling and cotyledon size, fresh weight, chlorophyll, and anthocyanin content but a slight increase in endogenous sugars. The addition of 100 mm sucrose (Suc) to the nitrogen-depleted growth media results in a further reduction in cotyledon size and chlorophyll content and an overall increase in anthocyanins and endogenous sugars. Storage lipid breakdown is almost completely blocked in seedlings grown on low nitrogen and 100 mm Suc and is significantly inhibited when seedlings are grown on either low nitrogen or high Suc. Carbohydrate repression of photosynthetic gene expression can only be observed under low nitrogen conditions. Low (0.1 mm) nitrogen in the absence of exogenous carbohydrate results in a significant decrease in chlorophyll a/b-binding protein and ribulose bisphosphate carboxylase small subunit gene transcript levels. Thus, carbon to nitrogen ratio rather than carbohydrate status alone appears to play the predominant role in regulating various aspects of seedling growth including storage reserve mobilization and photosynthetic gene expression.