title: Regulation of AhFRO1, an Fe(III)-chelate reductase of peanut, during iron deficiency stress and intercropping with maize.
abstract: Iron deficiency-induced chlorosis in peanut during anthesis was alleviated when peanut was intercropped with maize in field and pot experiments. Iron acquisition of graminaceous plants is characterized by the synthesis and secretion of the iron-chelating phytosiderophores. Compared to the roots of monocropped maize, the roots of maize intercropped with peanut always secreted higher amounts of phytosiderophores during peanut anthesis. For non-graminaceous plants, reduction of ferric to ferrous iron on the root surface is the rate-limiting step for mobilizing iron from soil. The full-length cDNA, AhFRO1, which is encoding an Fe(III)-chelate reductase, was isolated from peanut. AhFRO1 expression in yeast conferred Fe(III)-chelate reductase activity to the cells. Consistent with its function in iron uptake, AhFRO1 was determined to be a membrane protein by transient expression analysis. AhFRO1 mRNA accumulated under iron deficiency conditions. During pre-anthesis, the Fe(III)-chelate reductase activity and the transcript levels of AhFRO1 were similar in monocropped and intercropped peanut. When the iron deficiency-induced chlorosis developed in the monocropped peanuts, both the Fe(III)-chelate reductase activity of peanut and the transcript levels of AhFRO1 were higher in intercropped than in monocropped peanuts, which is consistent with the secretion of phytosiderophores by maize roots. We conclude that AhFRO1 in peanut and phytosiderophores from maize co-operate to improve the iron nutrition of peanut when intercropped with maize.
authors.affiliation: Key Laboratory of Plant and Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Ding
authors.forename: Lihong
authors.initials: L
authors.lastname: Duan
authors.forename: Huilan
authors.initials: H
authors.lastname: Wu
authors.forename: Rongxin
authors.initials: R
authors.lastname: Yang
authors.forename: Hongqing
authors.initials: H
authors.lastname: Ling
authors.forename: Wen-Xue
authors.initials: WX
authors.lastname: Li
authors.forename: Fusuo
authors.initials: F
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D010367:Arachis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D038181:FMN Reductase / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D000090463:Iron Deficiencies; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics; D016415:Sequence Alignment; D012987:Soil / Q000032:analysis; D003313:Zea mays / Q000378:metabolism / Q000502:physiology*
chemical_list: D018076:DNA, Complementary; D010940:Plant Proteins; D018749:RNA, Plant; D012987:Soil; D038181:FMN Reductase; C023903:ferric citrate iron reductase