title: Arabidopsis plastidial folylpolyglutamate synthetase is required for seed reserve accumulation and seedling establishment in darkness.
abstract: Interactions among metabolic pathways are important in plant biology. At present, not much is known about how folate metabolism affects other metabolic pathways in plants. Here we report a T-DNA insertion mutant (atdfb-3) of the plastidial folylpolyglutamate synthetase gene (AtDFB) was defective in seed reserves and skotomorphogenesis. Lower carbon (C) and higher nitrogen (N) content in the mutant seeds than that of the wild type were indicative of an altered C and N partitioning capacity. Higher levels of organic acids and sugars were detected in the mutant seeds compared with the wild type. Further analysis revealed that atdfb-3 seeds contained less total amino acids and individual Asn and Glu as well as NO3-. These results indicate significant changes in seed storage in the mutant. Defects in hypocotyl elongation were observed in atdfb-3 in darkness under sufficient NO3- conditions, and further enhanced under NO3- limited conditions. The strong expression of AtDFB in cotyledons and hypocotyl during early developmental stage was consistent with the mutant sensitivity to limited NO3- during a narrow developmental window. Exogenous 5-formyl-tetrahydrofolate completely restored the hypocotyl length in atdfb-3 seedlings with NO3- as the sole N source. Further study demonstrated that folate profiling and N metabolism were perturbed in atdfb-3 etiolated seedlings. The activity of enzymes involved in N reduction and assimilation was altered in atdfb-3. Taken together, these results indicate that AtDFB is required for seed reserves, hypocotyl elongation and N metabolism in darkness, providing novel insights into potential associations of folate metabolism with seed reserve accumulation, N metabolism and hypocotyl development in Arabidopsis.
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Meng
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China; National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Beijing, People's Republic of China.
authors.forename: Ling
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China.
authors.forename: Bosi
authors.initials: B
authors.lastname: Xu
authors.affiliation: Huazhong Agricultural University, Wuhan, People's Republic of China.
authors.forename: Wenzhu
authors.initials: W
authors.lastname: Guo
authors.affiliation: Beijing Institute of Pharmacology and Toxicology, Beijing, People's Republic of China.
authors.forename: Jinglai
authors.initials: J
authors.lastname: Li
authors.affiliation: Beijing Institute of Pharmacology and Toxicology, Beijing, People's Republic of China.
authors.forename: Xiuqing
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Institute of Botany, Chinese Academy of Sciences, Beijing, People's Republic of China.
authors.forename: Xiaoquan
authors.initials: X
authors.lastname: Qi
authors.affiliation: Institute of Botany, Chinese Academy of Sciences, Beijing, People's Republic of China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Duan
authors.affiliation: Institute of Botany, Chinese Academy of Sciences, Beijing, People's Republic of China.
authors.forename: Xianbin
authors.initials: X
authors.lastname: Meng
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China; National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Beijing, People's Republic of China.
authors.forename: Yunliu
authors.initials: Y
authors.lastname: Fan
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China; National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Beijing, People's Republic of China.
authors.forename: Chunyi
authors.initials: C
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D004269:DNA, Bacterial / Q000235:genetics; D003624:Darkness; D005492:Folic Acid / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D018525:Germination / Q000187:drug effects / Q000528:radiation effects; D018546:Hypocotyl / Q000187:drug effects / Q000254:growth & development / Q000528:radiation effects; D002955:Leucovorin / Q000494:pharmacology; D009154:Mutation; D009566:Nitrates / Q000378:metabolism; D009929:Organ Size; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism*; D018087:Plastids / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects*; D012639:Seeds / Q000187:drug effects / Q000254:growth & development* / Q000528:radiation effects*
chemical_list: D004269:DNA, Bacterial; D009566:Nitrates; C036483:T-DNA; D005492:Folic Acid; D010453:Peptide Synthases; C023103:folylpolyglutamate synthetase; D002955:Leucovorin