Genome-wide identification and transcriptional analysis of folate metabolism-related genes in maize kernels.
BACKGROUND
Maize is a major staple food crop globally and contains various concentrations of vitamins. Folates are essential water-soluble B-vitamins that play an important role as one-carbon (C1) donors and acceptors in organisms. To gain an understanding of folate metabolism in maize, we performed an intensive in silico analysis to screen for genes involved in folate metabolism using publicly available databases, followed by examination of the transcript expression patterns and profiling of the folate derivatives in the kernels of two maize inbred lines.


RESULTS
A total of 36 candidate genes corresponding to 16 folate metabolism-related enzymes were identified. The maize genome contains all the enzymes required for folate and C1 metabolism, characterized by highly conserved functional domains across all the other species investigated. Phylogenetic analysis revealed that these enzymes in maize are conserved throughout evolution and have a high level of similarity with those in sorghum and millet. The LC-MS analyses of two maize inbred lines demonstrated that 5-methyltetrahydrofolate was the major form of folate derivative in young seeds, while 5-formyltetrahydrofolate in mature seeds. Most of the genes involved in folate and C1 metabolism exhibited similar transcriptional expression patterns between these two maize lines, with the highest transcript abundance detected on day after pollination (DAP) 6 and the decreased transcript abundance on DAP 12 and 18. Compared with the seeds on DAP 30, 5-methyltetrahydrofolate was decreased and 5-formyltetrahydrofolate was increased sharply in the mature dry seeds.


CONCLUSIONS
The enzymes involved in folate and C1 metabolism are conserved between maize and other plant species. Folate and C1 metabolism is active in young developing maize seeds at transcriptional levels.
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. liantong9111@163.com.
Tong
T
Lian
Huazhong Agricultural University, Wuhan, People's Republic of China. guowenzhu0534@163.com.
Wenzhu
W
Guo
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. chenmaoran@qq.com.
Maoran
M
Chen
Beijing Institute of Pharmacology and Toxicology, Beijing, People's Republic of China. ljlai108@sina.cn.
Jinglai
J
Li
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. liangqj06@163.com.|National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Beijing, People's Republic of China. liangqj06@163.com.
Qiuju
Q
Liang
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. tbliufangcau@163.com.
Fang
F
Liu
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. mhy1984@126.com.
Hongyan
H
Meng
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. xbs2000@126.com.
Bosi
B
Xu
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. chenjinfengjiujiu@163.com.|Southwest University of Science and Technology, Mianyang, People's Republic of China. chenjinfengjiujiu@163.com.
Jinfeng
J
Chen
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. zhangchunyi@caas.cn.|National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Beijing, People's Republic of China. zhangchunyi@caas.cn.
Chunyi
C
Zhang
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China. jiangling@caas.cn.|National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Beijing, People's Republic of China. jiangling@caas.cn.
Ling
L
Jiang
D001203:Ascomycota / Q000502:physiology*; D005492:Folic Acid / Q000378:metabolism*; D018745:Genome, Plant; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D040641:Quantitative Trait Loci; D014158:Transcription, Genetic; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology*
D010940:Plant Proteins; D005492:Folic Acid