title: Overexpression of Arabidopsis VIT1 increases accumulation of iron in cassava roots and stems.
abstract: Iron is extremely abundant in the soil, but its uptake in plants is limited due to low solubility in neutral or alkaline soils. Plants can rely on rhizosphere acidification to increase iron solubility. AtVIT1 was previously found to be involved in mediating vacuolar sequestration of iron, which indicates a potential application for iron biofortification in crop plants. Here, we have overexpressed AtVIT1 in the starchy root crop cassava using a patatin promoter. Under greenhouse conditions, iron levels in mature cassava storage roots showed 3-4 times higher values when compared with wild-type plants. Significantly, the expression of AtVIT1 showed a positive correlation with the increase in iron concentration of storage roots. Conversely, young leaves of AtVIT1 transgenic plants exhibit characteristics of iron deficiency such as interveinal chlorosis of leaves (yellowing) and lower iron concentration when compared with the wild type plants. Interestingly, the AtVIT1 transgenic plants showed 4 and 16 times higher values of iron concentration in the young stem and stem base tissues, respectively. AtVIT1 transgenic plants also showed 2-4 times higher values of iron content when compared with wild-type plants, with altered partitioning of iron between source and sink tissues. These results demonstrate vacuolar iron sequestration as a viable transgenic strategy to biofortify crops and to help eliminate micronutrient malnutrition in at-risk human populations.
authors.affiliation: Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, MO 63132, USA. Electronic address: nnarayanan@danforthcenter.org.
authors.forename: Narayanan
authors.initials: N
authors.lastname: Narayanan
authors.affiliation: Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, MO 63132, USA.
authors.forename: Getu
authors.initials: G
authors.lastname: Beyene
authors.affiliation: Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, MO 63132, USA.
authors.forename: Raj Deepika
authors.initials: RD
authors.lastname: Chauhan
authors.affiliation: Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, MO 63132, USA.
authors.forename: Eliana
authors.initials: E
authors.lastname: Gaitán-Solis
authors.affiliation: USDA-ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street, Houston, TX 77030, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Grusak
authors.affiliation: Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, MO 63132, USA.
authors.forename: Nigel
authors.initials: N
authors.lastname: Taylor
authors.affiliation: Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, MO 63132, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Anderson
mesh_terms: D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D007501:Iron / Q000378:metabolism*; D002365:Manihot / Q000235:genetics / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D018547:Plant Stems / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D027682:Cation Transport Proteins; C515257:VIT1 protein, Arabidopsis; D007501:Iron
keywords: AtVIT1; Biofortification; Cassava; Iron; Source-sink