In silico, in vitro and in vivo characterisation of thiamin binding proteins from plant seeds.

Thiamin, an essential micronutrient, is a cofactor for enzymes involved in the central carbon metabolism and amino acids pathways. Despite efforts to enhance thiamin content in rice by incorporating thiamin biosynthetic genes, increasing thiamin content in endosperm remains challenging, possibly due to a lack of thiamin stability and/or a local sink. The introduction of storage proteins has been successful in biofortification strategies and similar efforts targeting thiamin led to a 3-4-fold increase in white rice.

Biofortification: Future Challenges for a Newly Emerging Technology to Improve Nutrition Security Sustainably.

Biofortification was coined as a term to define a plant breeding strategy to increase the micronutrient content of staple food crops to reduce the burden of micronutrient deficiencies in low- and middle-income countries. In 2003, the HarvestPlus program, based in the centers comprising the Consultative Group on International Agricultural Research, was initiated to implement the biofortification strategy. This article discusses what has been achieved, what has been learned, and the key challenges to embed biofortification in food systems and to expand its impact.

Cytokinins regulate spatially specific ethylene production to control root growth in Arabidopsis.

Two principal growth regulators, cytokinins and ethylene, are known to interact in the regulation of plant growth. However, information about the underlying molecular mechanism and positional specificity of cytokinin/ethylene crosstalk in the control of root growth is scarce. We have identified the spatial specificity of cytokinin-regulated root elongation and root apical meristem (RAM) size, both of which we demonstrate to be dependent on ethylene biosynthesis.

Arinole, a novel auxin-stimulating benzoxazole, affects root growth and promotes adventitious root formation.

The triple response phenotype is characteristic for seedlings treated with the phytohormone ethylene or its direct precursor 1-aminocyclopropane-carboxylic acid, and is often employed to find novel chemical tools to probe ethylene responses. We identified a benzoxazole-urea derivative (B2) partially mimicking ethylene effects in a triple response bioassay. A phenotypic analysis demonstrated that B2 and its closest analogue arinole (ARI) induced phenotypic responses reminiscent of seedlings with elevated levels of auxin, including impaired hook development and inhibition of seedling growth.

OsTH1 is a key player in thiamin biosynthesis in rice.

Thiamin is a vital nutrient that acts as a cofactor for several enzymes primarily localized in the mitochondria. These thiamin-dependent enzymes are involved in energy metabolism, nucleic acid biosynthesis, and antioxidant machinery. The enzyme HMP-P kinase/thiamin monophosphate synthase (TH1) holds a key position in thiamin biosynthesis, being responsible for the phosphorylation of HMP-P into HMP-PP and for the condensation of HMP-PP and HET-P to form TMP.