INVESTIGADORES
CABELLO Julieta Virginia
artículos
Título:
The intron of the Arabidopsis thaliana COX5c gene is able to improve the drought tolerance conferred by the sunfower Hahb-4 transcription factor
Autor/es:
JULIETA V. CABELLO, CARLOS A. DEZAR, PABLO A. MANAVELLA, RAQUEL L. CHAN
Revista:
PLANTA
Editorial:
SPRINGER
Referencias:
Año: 2007 vol. 226 p. 1143 - 1154
ISSN:
0032-0935
Resumen:
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Hahb-4 is a member of Helianthus annuus (sunflower) subfamily I of HD-Zip proteins. Transgenic Arabidopsis thaliana plants constitutively
expressing this gene exhibit a strong tolerance of water stress in concert with
morphological defects and a delay in development.
In order
to obtain a drought-tolerant phenotype without morphological associated
phenotype, several stress inducible promoters were isolated and transgenic
plants expressing Hahb-4 controlled
by them were prepared and analyzed. These plants showed unchanged morphology in
normal growth conditions and enhanced drought tolerance compared with non
transformed plants, but no as high as that exhibited by the constitutively
transformed genotype.
A
chimerical construction between Hahb-4
promoter and the leader intron of the Arabidopsis Cox5c gene was made either directing gus or Hahb-4 expression.
GUS activity increased in transgenic plants after induction, showing the same distribution
pattern. Transgenic plants, bearing the chimerical construct, are
indistinguishable from wild type plants in normal growth conditions whereas the
water stress tolerance achieved was as strong as that shown by the constitutive
genotype. This enhanced stress tolerance appeared to be due to a combination of
higher levels of transcription and translation in control growth conditions, increasing
at the same rate (transcript), or faster (protein) under stress, compared with
transcript/protein levels in plants transformed with the Hahb-4 promoter. Similar strategies could be applied in the future
for the obtaining of suitable promoters responsive to other external agents.
