Embryo-specific silencing of a transporter reduces phytic acid content of maize and soybean seeds.
Phytic acid in cereal grains and oilseeds is poorly digested by monogastric animals and negatively affects animal nutrition and the environment. However, breeding programs involving mutants with less phytic acid and more inorganic phosphate (P(i)) have been frustrated by undesirable agronomic characteristics associated with the phytic acid-reducing mutations. We show that maize lpa1 mutants are defective in a multidrug resistance-associated protein (MRP) ATP-binding cassette (ABC) transporter that is expressed most highly in embryos, but also in immature endosperm, germinating seed and vegetative tissues. Silencing expression of this transporter in an embryo-specific manner produced low-phytic-acid, high-Pi transgenic maize seeds that germinate normally and do not show any significant reduction in seed dry weight. This dominant transgenic approach obviates the need for incorporating recessive lpa1 mutations to create maize hybrids with reduced phytic acid. Suppressing the homologous soybean MRP gene also generated low-phytic-acid seed, suggesting that the strategy might be feasible for many crops.
Crop Genetics Research and Development, Pioneer Hi-Bred International, A DuPont Company, Johnston, Iowa 50131, USA. Jinrui.shi@Pioneer.com
Jinrui
J
Shi
Hongyu
H
Wang
Kathleen
K
Schellin
Bailin
B
Li
Marianna
M
Faller
Johan M
JM
Stoop
Robert B
RB
Meeley
David S
DS
Ertl
Jerry P
JP
Ranch
Kimberly
K
Glassman
D001483:Base Sequence; D020868:Gene Silencing; D005818:Genetic Engineering / Q000379:methods*; D008969:Molecular Sequence Data; D010833:Phytic Acid / Q000378:metabolism*; D010945:Plants, Edible / Q000235:genetics* / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000378:metabolism*; D012639:Seeds / Q000235:genetics* / Q000378:metabolism*; D013025:Glycine max / Q000502:physiology; D003313:Zea mays / Q000502:physiology
D010833:Phytic Acid