期刊
NEW PHYTOLOGIST
卷 232, 期 4, 页码 1750-1764出版社
WILEY
DOI: 10.1111/nph.17673
关键词
apochloritic; beta-ketoadipate pathway; Entner-Doudoroff pathway; glycolysis; lignin; mixotrophy; oxidative pentose phosphate pathway; photosynthesis
资金
- Fulbright Graduate Student Exchange Program (Ukraine)
- National Science Foundation (NSF) [DEB-1353131]
- Arkansas Biosciences Institute
- Arkansas Economic Development Commission
- NSF
By sequencing the genome of a nonphotosynthetic diatom, Nitzschia Nitz4, researchers found changes in carbon metabolism, including gene losses and metabolic reshaping within the cell. The lack of an oxidative pentose phosphate pathway in diatom plastids limits the available sources of NADPH in nonphotosynthetic plastids. The study suggests that the mode of NADPH provisioning in the plastid may play a significant role in constraining the loss of photosynthesis.
Although most of the tens of thousands of diatom species are photoautotrophs, a small number of heterotrophic species no longer photosynthesize. We sequenced the genome of a nonphotosynthetic diatom, Nitzschia Nitz4, to determine how carbon metabolism was altered in the wake of this trophic shift. Nitzschia Nitz4 has retained its plastid and plastid genome, but changes associated with the transition to heterotrophy were cellular-wide and included losses of photosynthesis-related genes from the nuclear and plastid genomes, elimination of isoprenoid biosynthesis in the plastid, and remodeling of mitochondrial glycolysis to maximize adenosine triphosphte (ATP) yield. The genome contains a beta-ketoadipate pathway that may allow Nitzschia Nitz4 to metabolize lignin-derived compounds. Diatom plastids lack an oxidative pentose phosphate pathway (oPPP), leaving photosynthesis as the primary source of NADPH to support essential biosynthetic pathways in the plastid and, by extension, limiting available sources of NADPH in nonphotosynthetic plastids. The genome revealed similarities between nonphotosynthetic diatoms and apicomplexan parasites for provisioning NADPH in their plastids and highlighted the ancestral absence of a plastid oPPP as a potentially important constraint on loss of photosynthesis, a hypothesis supported by the higher frequency of transitions to parasitism or heterotrophy in lineages that have a plastid oPPP.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据