1
|
Liu Z, Wang Z, Gu H, You J, Hu M, Zhang Y, Zhu Z, Wang Y, Liu S, Chen L, Liu X, Tian Y, Zhou S, Jiang L, Liu L, Wan J. Identification and Phenotypic Characterization of ZEBRA LEAF16 Encoding a β-Hydroxyacyl-ACP Dehydratase in Rice. FRONTIERS IN PLANT SCIENCE 2018; 9:782. [PMID: 29946330 PMCID: PMC6005893 DOI: 10.3389/fpls.2018.00782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 05/23/2018] [Indexed: 05/06/2023]
Abstract
The chloroplast is a self-independent organelle and contains its own transcription and translation systems. The establishment of genetic systems is vital for normal plant growth and development. We isolated a rice zebra leaf 16 (zl16) mutant derived from rice cultivar 9311. The zl16 mutant showed chlorotic abnormalities in the transverse sectors of the young leaves of seedlings. The use of transmission electron microscopy (TEM) demonstrated that dramatic defects occurred in variegated zl16 leaves during the early development of a chloroplast. Map-based cloning revealed that ZL16 encodes a β-hydroxyacyl-ACP dehydratase (HAD) involved in de novo fatty acid synthesis. Compared with the wild type, a missense mutation (Arg164Trp) in the zl16 mutant was identified, which significantly reduced enzymatic activity and altered the three-dimensional modeling structure of the putative protein. ZL16 was ubiquitously expressed in various plant organs, with a pronounced level in the young leaf. A subcellular localization experiment indicated that ZL16 was targeted in the chloroplast. Furthermore, we analyzed the expression of some nuclear genes involved in chloroplast development, and found they were altered in the zl16 mutant. RNA-Seq analysis indicated that some genes related to cell membrane constituents were downregulated in the mutant. An in vivo metabolic assay revealed that the total fatty acid content in the mutant was significantly decreased relative to the wild type. Our results indicate that HAD is essential for the development of chloroplasts by regulating the synthesis of fatty acids in rice.
Collapse
Affiliation(s)
- Ziwen Liu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Zhiyuan Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Han Gu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Jia You
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Manman Hu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Yujun Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Ze Zhu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Yihua Wang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Shijia Liu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Liangming Chen
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Xi Liu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Yunlu Tian
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Shirong Zhou
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Ling Jiang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
| | - Linglong Liu
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
- *Correspondence: Linglong Liu,
| | - Jianmin Wan
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, Jiangsu Plant Gene Engineering Research Center, Nanjing Agricultural University, Nanjing, China
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|
2
|
Li S, Nosenko T, Hackett JD, Bhattacharya D. Phylogenomic analysis identifies red algal genes of endosymbiotic origin in the chromalveolates. Mol Biol Evol 2005; 23:663-74. [PMID: 16357039 DOI: 10.1093/molbev/msj075] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Endosymbiosis has spread photosynthesis to many branches of the eukaryotic tree; however, the history of photosynthetic organelle (plastid) gain and loss remains controversial. Fortuitously, endosymbiosis may leave a genomic footprint through the transfer of endosymbiont genes to the "host" nucleus (endosymbiotic gene transfer, EGT). EGT can be detected through comparison of host genomes to uncover the history of past plastid acquisitions. Here we focus on a lineage of chlorophyll c-containing algae and protists ("chromalveolates") that are postulated to share a common red algal secondary endosymbiont. This plastid is originally of cyanobacterial origin through primary endosymbiosis and is closely related among the Plantae (i.e., red, green, and glaucophyte algae). To test these ideas, an automated phylogenomics pipeline was used with a novel unigene data set of 5,081 expressed sequence tags (ESTs) from the haptophyte alga Emiliania huxleyi and genome or EST data from other chromalveolates, red algae, plants, animals, fungi, and bacteria. We focused on nuclear-encoded proteins that are targeted to the plastid to express their function because this group of genes is expected to have phylogenies that are relatively easy to interpret. A total of 708 genes were identified in E. huxleyi that had a significant Blast hit to at least one other taxon in our data set. Forty-six of the alignments that were derived from the 708 genes contained at least one other chromalveolate (i.e., besides E. huxleyi), red and/or green algae (or land plants), and one or more cyanobacteria, whereas 15 alignments contained E. huxleyi, one or more other chromalveolates, and only cyanobacteria. Detailed phylogenetic analyses of these data sets turned up 19 cases of EGT that did not contain significant paralogy and had strong bootstrap support at the internal nodes, allowing us to confidently identify the source of the plastid-targeted gene in E. huxleyi. A total of 17 genes originated from the red algal lineage, whereas 2 genes were of green algal origin. Our data demonstrate the existence of multiple red algal genes that are shared among different chromalveolates, suggesting that at least a subset of this group may share a common origin.
Collapse
Affiliation(s)
- Shenglan Li
- Department of Biological Sciences and Roy J. Carver Center for Comparative Genomics, University of Iowa, USA
| | | | | | | |
Collapse
|
3
|
Yoon HS, Hackett JD, Pinto G, Bhattacharya D. The single, ancient origin of chromist plastids. Proc Natl Acad Sci U S A 2002; 99:15507-12. [PMID: 12438651 PMCID: PMC137747 DOI: 10.1073/pnas.242379899] [Citation(s) in RCA: 306] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2002] [Indexed: 11/18/2022] Open
Abstract
Algae include a diverse array of photosynthetic eukaryotes excluding land plants. Explaining the origin of algal plastids continues to be a major challenge in evolutionary biology. Current knowledge suggests that plastid primary endosymbiosis, in which a single-celled protist engulfs and "enslaves" a cyanobacterium, likely occurred once and resulted in the primordial alga. This eukaryote then gave rise through vertical evolution to the red, green, and glaucophyte algae. However, some modern algal lineages have a more complicated evolutionary history involving a secondary endosymbiotic event, in which a protist engulfed an existing eukaryotic alga (rather than a cyanobacterium), which was then reduced to a secondary plastid. Secondary endosymbiosis explains the majority of algal biodiversity, yet the number and timing of these events is unresolved. Here we analyzed a five-gene plastid data set to show that a taxonomically diverse group of chlorophyll c(2)-containing protists comprising cryptophyte, haptophyte, and stramenopiles algae (Chromista) share a common plastid that most likely arose from a single, ancient ( approximately 1,260 million years ago) secondary endosymbiosis involving a red alga. This finding is consistent with Chromista monophyly and implicates secondary endosymbiosis as an important force in generating eukaryotic biodiversity.
Collapse
Affiliation(s)
- Hwan Su Yoon
- Department of Biological Sciences and Center for Comparative Genomics, University of Iowa, 210 Biology Building, Iowa City 52242, USA
| | | | | | | |
Collapse
|