Co-expression analysis revealed that the expression of some sORFs was positively correlated with the genes upregulated by Fe deficiency. In contrast, 1509 genes were upregulated by Fe deficiency, of which 90 (6%) were sORFs. In roots, 36 genes were upregulated by excess Fe, of which three were sORFs. Results: We used a novel rice 110 K microarray harbouring ~48,620 sORFs to understand the transcriptomic changes that occur in response to Fe deficiency and excess. Understanding the regulation of rice transcriptome in response to Fe deficiency and excess could provide bases for developing strategies to breed plants tolerant to Fe deficiency as well as excess Fe. Moreover, the regulation of small open reading frames (sORFs) in response to abiotic stress has not been reported in rice. The mechanisms of Fe deficiency are reasonably understood, however our knowledge about plants response to excess Fe is limited. These findings suggest that the induction of local Fe deficiency in the mitochondrial compartment of mit-2 plants differentially affects the transcript as well as the metabolic profiles in root and shoot tissues.īackground: Iron (Fe) is essential micronutrient for plants and its deficiency as well as toxicity is a serious agricultural problem. pyruvic acid, fumaric acid, ornithine, and oligosaccharides of the raffinose family) accumulated only in the shoot of mit-2 plants, indicating possible hypoxic responses. Significant alterations in the levels of amino acids belonging to the aspartic acid-related pathways (aspartic acid, lysine, and threonine in roots, and aspartic acid and ornithine in shoots) were found that are strictly connected to the Krebs cycle. This was reflected by changes in the metabolic profiles in both roots and shoots of mit-2 plants. In particular, a strong alteration (up-/down-regulation) in the expression of genes encoding enzymes of both primary and secondary metabolism was found in mutant plants. Additionally, large-scale changes in the transcriptome and metabolome were observed in mit-2 rice plants. In particular, proteins belonging to the type II alternative NAD(P)H dehydrogenases accumulated strongly in mit-2 plants, indicating that alternative pathways were activated to keep the respiratory chain working. Biochemical characterization of purified mitochon-dria from rice roots showed alteration in the respiratory chain of mit-2 compared with wild-type (WT) plants.

In this work, the metabolic adjustment in the rice (Oryza sativa) mitochon-drial Fe transporter knockdown mutant (mit-2) was analysed. Iron (Fe) is an essential micronutrient for plant growth and development, and its reduced bioavailability strongly impairs mitochondrial functionality.

Shimo fujimoto