INVESTIGADORES
ROUSSEAUX Maria Cecilia
artículos
Título:
Directed overexpression of PHYA locally suppresses stem elongation and leaf senescence responses to far-red radiation.
Autor/es:
ROUSSEAUX, M. C.; BALLARE, C. L.; JORDAN, E. T.; VIESTRA, R. D.
Revista:
PLANT, CELL AND ENVIRONMENT (PRINT)
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Año: 1997 vol. 20 p. 1551 - 1558
ISSN:
0140-7791
Resumen:
Ectopic overexpression of an oat PHYA cDNA in tobaccounder the cauliflower mosaic virus 35S promoter results inplants with reduced morphological responses to far-redradiation (FR). We have tested the hypothesis that it is possibleto molecularly ´mask´ stems and leaves to FR-inducedelongation and senescence responses by targeting the overexpressionol´PHYA with appropriate promoters. Oat PHYAwas expressed in tobacco {Nicotiana tahacum L. cv Xanthi)under the 35S and two Arabidopsis promoters: UBQl andCAB. The internodes of wild type, UBQ.PHYA, andCAB.PHYA plants, which exhibited little or no oat PHYAoverexpression, responded to locali/.ed FR treatments with amarked increase in elongation. In contrast, 35S:PHYAplants, which overexpressed PHYA to high levels in all partsof the shoot, did not respond to FR treatments directed totheir stems. Leaf senescence responses to FR were remarkablylocalized, and sensitivity to FR was also inversely correlatedwith the local PHYA expression level. Thus, chlorophyllcontent, specific leaf weight, and nitrate reductaseactivity in leaf spots treated with FR were highly reduced inwild type and UBQ:PHYA plants, but not in the CAB.PHYAand 35S:PHYA counterparts. Our results suggest that it maybe feasible to obtain transgenie crop plants in which certainorgans or tissues are made ´blind´ to phytochrome-perceivedsignals of canopy density, but whose general photoniorpbogeniccompetence is not greatly disturbed.