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Alternative oxidase involvement in Daucus carota somatic embryogenesis
Author(s) -
Frederico António Miguel,
Campos Maria Doroteia,
Cardoso Hélia Guerra,
Imani Jafargholi,
ArnholdtSchmitt Birgit
Publication year - 2009
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2009.01278.x
Subject(s) - daucus carota , alternative oxidase , somatic embryogenesis , biology , reprogramming , microbiology and biotechnology , somatic cell , embryogenesis , salicylhydroxamic acid , biochemistry , embryo , botany , mitochondrion , cell , gene , enzyme
Plant alternative oxidase (AOX) is a mitochondrial inner membrane enzyme involved in alternative respiration. The critical importance of the enzyme during acclimation upon stress of plant cells is not fully understood and is still an issue of intensive research and discussion. Recently, a role of AOX was suggested for the ability of plant cells to change easily its fate upon stress. In order to get new insights about AOX involvement in cell reprogramming, quantitative real‐time polymerase chain reaction (PCR) and inhibitor studies were performed during cell redifferentiation and developmental stages of Daucus carota L. somatic embryogenesis. Transcript level analysis shows that D. carota AOX genes ( DcAOX1a and DcAOX2a ) are differentially expressed during somatic embryogenesis. DcAOX1a shows lower expression levels, being mainly down‐regulated, whereas DcAOX2a presented a large up‐regulation during initiation of the realization phase of somatic embryogenesis. However, when globular embryos start to develop, both genes are down‐regulated, being this state transient for DcAOX2a . In addition, parallel studies were performed using salicylhydroxamic acid (SHAM) in order to inhibit AOX activity during the realization phase of somatic embryogenesis. Embryogenic cells growing in the presence of the inhibitor were unable to develop embryogenic structures and its growth rate was diminished. This effect was reversible and concentration dependent. The results obtained contribute to the hypothesis that AOX activity supports metabolic reorganization as an essential part of cell reprogramming and, thus, enables restructuring and de novo cell differentiation.