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Wang Y, Wang J, Chen L, Meng X, Zhen X, Liang Y, Han Y, Li H, Zhang B. Identification and function analysis of yellow-leaf mutant (YX-yl) of broomcorn millet. BMC Plant Biol 2022; 22:463. [PMID: 36167497 PMCID: PMC9513943 DOI: 10.1186/s12870-022-03843-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 09/12/2022] [Indexed: 05/30/2023]
Abstract
BACKGROUND Broomcorn millet is highly tolerant to drought and barren soil. Changes in chlorophyll content directly affect leaf color, which subsequently leadsleading to poor photosynthetic performance and reduced crop yield. Herein, we isolated a yellow leaf mutant (YX-yl) using a forward genetics approach and evaluated its agronomic traits, photosynthetic pigment content, chloroplast ultrastructure, and chlorophyll precursors. Furthermore, the molecular mechanism of yellowing was explored using transcriptome sequencing. RESULTS The YX-yl mutant showed significantly decreased plant height and low yield. The leaves exhibited a yellow-green phenotype and poor photosynthetic capacity during the entire growth period. The content of chlorophyll a, chlorophyll b, and carotenoids in YX-yl leaves was lower than that in wild-type leaves. Chlorophyll precursor analysis results showed that chlorophyll biosynthesis in YX-yl was hindered by the conversion of porphobilinogen to protoporphyrin IX. Examination of chloroplast ultrastructure in the leaves revealed that the chloroplasts of YX-yl accumulated on one side of the cell. Moreover, the chloroplast structure of YX-yl was degraded. The inner and outer membranes of the chloroplasts could not be distinguished well. The numbers of grana and grana thylakoids in the chloroplasts were low. The transcriptome of the yellowing mutant YX-yl was sequenced and compared with that of the wild type. Nine chlorophyll-related genes with significantly different expression profiles were identified: PmUROD, PmCPO, PmGSAM, PmPBDG, PmLHCP, PmCAO, PmVDE, PmGluTR, and PmPNPT. The proteins encoded by these genes were located in the chloroplast, chloroplast membrane, chloroplast thylakoid membrane, and chloroplast matrix and were mainly involved in chlorophyll biosynthesis and redox-related enzyme regulation. CONCLUSIONS YX-yl is an ideal material for studying pigment metabolism mechanisms. Changes in the expression patterns of some genes between YX-yl and the wild type led to differences in chloroplast structures and enzyme activities in the chlorophyll biosynthesis pathway, ultimately resulting in a yellowing phenotype in the YX-yl mutant. Our findings provide an insight to the molecular mechanisms of leaf color formation and chloroplast development in broomcorn millet.
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Affiliation(s)
- Yushen Wang
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
- Shanxi Key Laboratory of Germplasm Innovation and Molecular Breeding of Minor Crop, Taigu, Shanxi, China, 030801
- Ministerial and Provincial Co-Innovation Centre for Endemic Crops Production With High-Quality and Efficiency in Loess Plateau, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
| | - Junjie Wang
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
| | - Liqing Chen
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
| | - Xiaowei Meng
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
| | - Xiaoxi Zhen
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
| | - Yinpei Liang
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
| | - Yuanhuai Han
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
- Shanxi Key Laboratory of Germplasm Innovation and Molecular Breeding of Minor Crop, Taigu, Shanxi, China, 030801
| | - Hongying Li
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801
| | - Bin Zhang
- College of Agriculture, Shanxi Agricultural University, Taigu, Shanxi, China, 030801.
- Shanxi Key Laboratory of Germplasm Innovation and Molecular Breeding of Minor Crop, Taigu, Shanxi, China, 030801.
- Ministerial and Provincial Co-Innovation Centre for Endemic Crops Production With High-Quality and Efficiency in Loess Plateau, Shanxi Agricultural University, Taigu, Shanxi, China, 030801.
- Institute of Agricultural Bioengineering, Shanxi Agricultural University, Taigu, Shanxi, China, 030801.
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