Expression of sunflower cytocrome c mRNA is tissue-specific and controlled by nitrate and light

FELITTI, S.; CHAN, R.; GAGO, G.; VALLE, E.; GONZALEZ, D.

PHYSIOLOGIA PLANTARUM

WILEY

Año: 1997 vol. 99 p. 342 - 347

0031-9317

A PCR-based strategy with two degenerate oligonucleotides followed by libraryscreening was used to isolate a 590-bp cDNA clone encoding a ftill-length apocytochromec polypeptide from a sunflower (Helianlhus annuus L. line HA401B) root library.The sequence of the encoded polypeptide (112 amino acids) differs from thepreviously reported protein sequence (Ramshaw et al. 1970. Biochem. J. 119: 535-539) at four positions. Southern blot analysis indicates the possible existence of twodifferent cytochrome c genes in sunflower. The isolated cDNA clone was used to performexpression studies of cytochrome c mRNA(s) in different stmflower organs andunder different conditions. Higher transcript levels were observed in flowers and rootsrelative to leaves, stems, hypocotyls and cotyledons. Light promoted an increase inthe expression of cytochrome c mRNA in 6-day-old seedlings. Nitrate treatment, intum, reduced expression in roots. It is concluded that the steady-state mRNA levels ofcytochrome c encoding transcripts in sunflower are subject to tissue-specific regulationand also respond to environmental factors.