Esquível M G, Matos A R, Marques Silva J
Landscape, Environment, Agriculture and Food (LEAF), Instituto Superior de Agronomia (ISA), Universidade de Lisboa, Lisbon, Portugal.
Biossistems and Integrative Sciences Institute (BioISI), Dep. de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
Appl Microbiol Biotechnol. 2017 Jul;101(13):5569-5580. doi: 10.1007/s00253-017-8322-5. Epub 2017 May 19.
Photosynthesis and lipid allocation were investigated in Rubisco small subunit mutants of the microalga Chlamydomonas reinhardtii. Comparative analyses were undertaken with cells grown photoheterotrophically under sulphur-replete or sulphur-depleted conditions. The Y67A Rubisco mutant, which has previously demonstrated a pronounced reduction in Rubisco levels and higher hydrogen production rates than the wild type, also shows the following divergences in photosynthetic phenotype and lipid allocation: (i) low Fv/Fm (maximum photochemical efficiency), (ii) low effective quantum yield of photosystem II (ΦPSII), (iii) low effectiveness at protection against high light intensities, (iv) a higher level of total lipids per pigment and (v) changes in the relative proportions of different fatty acids, with a marked decrease in unsaturated fatty acids (FAs). The most abundant thylakoid membrane lipid, monogalactosyldiacylglycerol, decreased in amount, while the neutral lipid/polar lipid ratio increased in the mutant. The low amount and activity of the mutated Rubisco Y67A enzyme seems to have an adverse effect on photosynthesis and causes changes in carbon allocation in terms of membrane fatty acid composition and storage lipid accumulation. Our results suggest that Rubisco mutants of Chlamydomonas might be useful in biodiesel production.
对莱茵衣藻的核酮糖-1,5-二磷酸羧化酶小亚基突变体的光合作用和脂质分配进行了研究。对在硫充足或硫缺乏条件下光异养生长的细胞进行了比较分析。Y67A核酮糖-1,5-二磷酸羧化酶突变体先前已证明其核酮糖-1,5-二磷酸羧化酶水平显著降低，且产氢率高于野生型，该突变体在光合表型和脂质分配方面还表现出以下差异：（i）Fv/Fm（最大光化学效率）较低，（ii）光系统II的有效量子产率（ΦPSII）较低，（iii）抵御高光强度的能力较低，（iv）每色素的总脂质水平较高，以及（v）不同脂肪酸的相对比例发生变化，不饱和脂肪酸（FAs）显著减少。最丰富的类囊体膜脂质单半乳糖基二酰基甘油的含量减少，而突变体中的中性脂质/极性脂质比率增加。突变的核酮糖-1,5-二磷酸羧化酶Y67A酶的低含量和活性似乎对光合作用有不利影响，并导致膜脂肪酸组成和储存脂质积累方面的碳分配变化。我们的结果表明，衣藻的核酮糖-1,5-二磷酸羧化酶突变体可能在生物柴油生产中有用。
