IBBM   21076
INSTITUTO DE BIOTECNOLOGIA Y BIOLOGIA MOLECULAR
Unidad Ejecutora - UE
artículos
Título:
Expression of the minor isoform pea ferredoxin in tobacco alters photosynthetic electron partitioning and enhances cyclic electron flow
Autor/es:
BLANCO, NICOLÁS E.; CECCOLI, ROMINA D.; DALLA VIA, MARÍA D.; VOSS, INGO; SEGRETIN, MARÍA E.; BRAVO-ALMONACID, FERNANDO F.; MELZER, MICHAEL; HAJIREZAEI, MOHAMMAD-REZA; SCHEIBE, RENATE; HANKE, GUY T.
Revista:
PLANT PHYSIOLOGY.
Editorial:
AMER SOC PLANT BIOLOGISTS
Referencias:
Lugar: Rockville; Año: 2013 vol. 161 p. 866 - 879
ISSN:
0032-0889
Resumen:
Ferredoxins (Fd) are ferrosulfoproteins that function as low-potential electron carriers in plants. The Fd family is composed of several isoforms that share high sequence homology, but differ in functional characteristics. In leaves, at least two isoforms conduct linear and cyclic photosynthetic electron transport around photosystem I (LEF and CEF-PSI), and mounting evidence suggests the existence of at least partial division of duties between these isoforms. To evaluate the contribution of different kinds of Fd to the control of electron fluxes along the photosynthetic electron transport chain (PETC), we overexpressed a minor pea (Pisum sativum) Fd isoform (PsFd1) in tobacco (Nicotiana tabacum) plants. The transplastomic OeFd1 plants exhibited variegated leaves and retarded growth and developmental rates. Photosynthetic studies of these plants indicated a reduction in CO2 assimilation rates, PSII photochemistry and LEF. However, the plants showed an increase in non photochemical quenching (NPQ), better control of excitation pressure at PSII and no evidence of photoinhibition implying a better dynamic regulation to remove excess energy from the PETC. Finally, analysis of P700 redox status during illumination confirmed that the minor pea Fd isoform promotes enhanced CEF-PSI. The two novel features of this work are: firstly, Fd levels achieved in transplastomic plants promote an alternative electron partitioning even under greenhouse light growth conditions, a situation that is exacerbated at higher light intensity measurements; and secondly, this is the first time an alternative, minor Fd isoform has been overexpressed in plants, giving new evidence of labor division among Fd isoforms.