This article has been evaluated in Faculty of 1000 Biology. ISSN 1740-4118
We show that seed-specific overexpression of the sunflower (Helianthus
annuus) HaHSFA9 heat stress transcription factor (HSF) in tobacco (Nicotiana
tabacum) enhances the accumulation of heat-shock proteins (HSPs). Among
these proteins were HSP101 and a subset of the small HSPs (sHSPs),
including proteins that accumulate only during embryogenesis in the absence of
thermal stress. Levels of Late Embryogenesis Abundant proteins or seed
oligosaccharides, however, were not affected. In the transgenic seeds, a high
basal thermotolerance persisted during the early hours of imbibition. Transgenic
seeds also showed significantly improved resistance to controlled deterioration
in a stable and transgene-dependent manner. Furthermore, overexpression of
HaHSFA9 did not have detrimental effects on plant growth or development,
including seed morphology and total seed yield. Our results agree with previous
work tentatively associating HSP gene expression with phenotypes important
for seed longevity. These findings might have implications for improving seed
longevity in economically important crops.
This work was supported by the Spanish Ministry of Education and
Science (grants no. BIO02-1463 and BIO05-0949). We also received partial
support from the Andalusian Regional Government (“Junta de Andalucía”, grant
CVI148).
Peer reviewed