Investigation of a His-rich arabinogalactan-protein for micronutrient biofortification of cereal grain

Wan Mohd Aizat Wan Kamaruddin, James M. Preuss, Alexander A T Johnson, Mark A. Tester, Carolyn J. Schultz

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

The micronutrient content of most cereal grains is low and responsible for malnutrition deficiencies in millions of people who rely on grains as their primary food source. Any strategy that can increase the micronutrient content of grain will have significant benefits to world health. We identified a gene from barley encoding a cell wall protein with multiple histidine (His)-rich motifs interspersed with short arabinogalactan-protein (AGP) domains and have called it Hordeum vulgare His-rich AGP (HvHRA1). Sequence analysis shows that His-rich AGPs are rare in plants and that the number of His-rich and AGP domains differ between cereals and dicots. The barley and wheat encoded proteins have more than 13 His-rich domains, whereas the putative rice orthologue has only 5 His-rich regions. His-rich motifs are well-established metal-binding motifs; therefore, we developed transgenic (Tx) rice plants that constitutively overexpress barley HvHRA1. There was no significant effect on plant growth or grain yield in Tx plants. Purification of AGPs from wild-type and Tx plants showed that only Tx plants contained detectable levels of a His-rich AGP. Calcein assay shows that the AGP fraction from Tx plants had increased binding affinity for Cu2+. Micronutrient analysis of brown and white rice showed that the grain nutrient yield for Fe, Zn and Cu was higher in two Tx lines compared to their respective nulls, although the differences were not statistically significant. This approach highlights the potential of the plant apoplast (cell wall) for storage of key nutrients through overexpression of genes for metal-binding proteins.

Original languageEnglish
Pages (from-to)271-286
Number of pages16
JournalPhysiologia Plantarum
Volume143
Issue number3
DOIs
Publication statusPublished - Nov 2011
Externally publishedYes

Fingerprint

biofortification
arabinogalactan proteins
Micronutrients
histidine
small cereal grains
Histidine
Hordeum
barley
Food
Cell Wall
rice
Metals
metals
cell walls
Plant Cells
gene overexpression
Edible Grain
histidine-rich proteins
Biofortification
apoplast

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology
  • Genetics
  • Physiology

Cite this

Investigation of a His-rich arabinogalactan-protein for micronutrient biofortification of cereal grain. / Wan Kamaruddin, Wan Mohd Aizat; Preuss, James M.; Johnson, Alexander A T; Tester, Mark A.; Schultz, Carolyn J.

In: Physiologia Plantarum, Vol. 143, No. 3, 11.2011, p. 271-286.

Research output: Contribution to journalArticle

Wan Kamaruddin, Wan Mohd Aizat ; Preuss, James M. ; Johnson, Alexander A T ; Tester, Mark A. ; Schultz, Carolyn J. / Investigation of a His-rich arabinogalactan-protein for micronutrient biofortification of cereal grain. In: Physiologia Plantarum. 2011 ; Vol. 143, No. 3. pp. 271-286.
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