Department of Botany, University of Georgia, 30602, Athens, GA, USA.
Photosynth Res. 1993 Mar;35(3):219-26. doi: 10.1007/BF00016553.
Modulation of the activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in low light and darkness was measured in A) 25 genotypes from the four cultivated species of Phaseolus (P. vulgaris, P. acutifolius, P. lunatus and P. coccineus), B) 8 non-cultivated Phaseolus species, and C) the related species Macroptileum atropurpureum. The activity ratio of Rubisco (the ratio of initial and total Rubisco activities, which reflects Rubisco carbamylation), and the molar activity of fully-activated Rubisco (which primarily reflects the inhibition of Rubisco activity by carboxyarabinitol 1-phosphate, CA1P) were assayed in leaves from the cultivated species sampled at midday in full sunlight, in low light at dusk (60 to 100 μmol photons m(-2)s(-1)), and after at least 4 h in darkness. Dark inhibition of Rubisco molar activity was compared in both cultivated and non-cultivated species. In all cultivated genotypes, a significant reduction of the activity ratio of Rubisco was measured in leaves sampled at low light; however, the molar activity of fully activated Rubisco was not greatly reduced in these low light samples. In darkened leaves, molar activities substantially declined in most Phaseolus species with 11 of 13 exhibiting greater than 60% reduction. In P. vulgaris, the reduction of molar activity was extensive (greater than 69%) in all genotypes studied, which included wild progenitors as well as ancient and advanced cultivars. These results indicate that at low light late in the day, modulation of Rubisco activity is primarily through changes in carbamylation state, with CA1P playing a more limited role. By contrast in the dark, binding of CA1P dominates the modulation of Rubisco activity in Phaseolus in a pattern that appears to be conserved within a species, but can vary significantly between species within a genus. The degree of CA1P inhibition in Phaseolus was associated with phylogenetic affinities within the genus, as the species with extensive dark-inhibition of Rubisco activity tended to be more closely related to each other than to species with reduced inhibition of Rubisco activity.
在 A) 25 种来自菜豆属的四个栽培种（普通菜豆、多叶菜豆、利马豆和红花菜豆）、B) 8 种非栽培菜豆种和 C) 相关种 Macroptileum atropurpureum 中测量了在低光照和黑暗下核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）活性的调节。在中午全光照下、黄昏时（60 至 100 μmol 光子 m(-2)s(-1)）和至少 4 小时黑暗后，测定了来自四个栽培种的叶片中 Rubisco 的活性比（初始和总 Rubisco 活性的比值，反映 Rubisco 的氨甲酰化）和完全激活的 Rubisco 的摩尔活性（主要反映 1-磷酸核酮糖对 Rubisco 活性的抑制，CA1P）。比较了在栽培和非栽培种中 Rubisco 摩尔活性的暗抑制。在所有栽培基因型中，在低光照下取样的叶片中 Rubisco 的活性比显著降低；然而，这些低光样本中完全激活的 Rubisco 的摩尔活性并没有大大降低。在黑暗中，在 13 个种中的 11 个种中，摩尔活性大幅下降，超过 60%。在普通菜豆中，所有研究的基因型中摩尔活性的降低都很广泛（大于 69%），包括野生祖先和古老的和先进的品种。这些结果表明，在一天中光照较弱的傍晚，Rubisco 活性的调节主要是通过氨甲酰化状态的变化来实现的，而 CA1P 则起了更有限的作用。相比之下，在黑暗中，CA1P 的结合主导了 Rubisco 活性在菜豆中的调节，这种模式似乎在一个种内是保守的，但在一个属内的不同种之间可能有很大的差异。菜豆中 CA1P 抑制的程度与属内的系统发育关系有关，因为 Rubisco 活性暗抑制广泛的种彼此之间的关系比 Rubisco 活性抑制程度降低的种更为密切。
