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Ma YY, Shi JC, Wang DJ, Liang X, Wei F, Gong CM, Qiu LJ, Zhou HC, Folta KM, Wen YQ, Feng JY. A point mutation in the gene encoding Mg-chelatase subunit I influences strawberry leaf color and metabolism. Plant Physiol 2023:7136678. [PMID: 37086480 DOI: 10.1093/plphys/kiad247] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/09/2023] [Accepted: 03/25/2023] [Indexed: 05/03/2023]
Abstract
Magnesium chelatase catalyzes the insertion of magnesium into protoporphyrin IX, a vital step in chlorophyll biogenesis. The enzyme consists of three subunits, (Magnesium chelatase I subunit, CHLI), (Magnesium chelatase D subunit, CHLD) and (Magnesium chelatase H subunit, CHLH). The CHLI subunit is an ATPase that mediates catalysis. Previous studies on CHLI have mainly focused on model plant species, and its functions in other species have not been well described, especially with regard to leaf coloration and metabolism. In this study, we identified and characterized a CHLI mutant in strawberry species Fragaria pentaphylla. The mutant, noted as p240, exhibits yellow-green leaves and a low chlorophyll (Chl) level. RNA-seq identified a mutation in the 186th amino acid of the CHLI subunit, a base conserved in most photosynthetic organisms. Transient transformation of wild-type CHLI into p240 leaves complemented the mutant phenotype. Further mutants generated from RNA-interference (RNAi) and CRISPR/Cas9 gene editing recapitulated the mutant phenotype. Notably, heterozygous chli mutants accumulated more chlorophyll under low light conditions compared to high light conditions. Metabolite analysis of null mutants under high light conditions revealed substantial changes in both nitrogen and carbon metabolism. Further analysis indicated that mutation in Glu186 of CHLI does not affect its subcellular localization, nor the interaction between CHLI and CHLD. However, intramolecular interactions were impaired, leading to reduced ATPase and magnesium chelatase activity. These findings demonstrate that Glu186 plays a key role in enzyme function, affecting leaf coloration via the formation of the hexameric ring itself, and that manipulation of CHLI may be a means to improve strawberry plant fitness and photosynthetic efficiency under low light conditions.
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Affiliation(s)
- Yang-Yang Ma
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Key Laboratory of Protected Horticulture Engineering in Northwest China, Ministry of Agriculture and Rural Affairs, Yangling 712100, Shaanxi, China
| | - Jian-Cheng Shi
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Key Laboratory of Protected Horticulture Engineering in Northwest China, Ministry of Agriculture and Rural Affairs, Yangling 712100, Shaanxi, China
| | - Dan-Juan Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Key Laboratory of Protected Horticulture Engineering in Northwest China, Ministry of Agriculture and Rural Affairs, Yangling 712100, Shaanxi, China
| | - Xia Liang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Key Laboratory of Protected Horticulture Engineering in Northwest China, Ministry of Agriculture and Rural Affairs, Yangling 712100, Shaanxi, China
| | - Feng Wei
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Key Laboratory of Protected Horticulture Engineering in Northwest China, Ministry of Agriculture and Rural Affairs, Yangling 712100, Shaanxi, China
| | - Chun-Mei Gong
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Li-Juan Qiu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Key Laboratory of Protected Horticulture Engineering in Northwest China, Ministry of Agriculture and Rural Affairs, Yangling 712100, Shaanxi, China
| | - Hou-Cheng Zhou
- Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou 450009, Henan, China
| | - Kevin M Folta
- Horticultural Sciences Department, University of Florida, Gainesville, FL, United States
| | - Ying-Qiang Wen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jia-Yue Feng
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China
- Key Laboratory of Protected Horticulture Engineering in Northwest China, Ministry of Agriculture and Rural Affairs, Yangling 712100, Shaanxi, China
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