EFFECT OF DROUGHT AND COLD STRESS ON BLUEBERRY DEHYDRIN EXPRESSION

Authors: PANTA, GANESH - CONTRACT EMPLOYEE; Rowland, Lisa

Submitted to: Blueberry Research Extension North American Workers Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/27/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Dehydrins are a group of plant proteins that are induced by
environmental stresses that have a dehydration component
including drought, cold stress, salinity, and seed maturation.
Previously three dehydrins (65, 60, and 14 kilodaltons in size)
were identified as the most abundant proteins present in cold
hardy blueberry flower buds. Levels were shown to increase with
development of cold hardiness and decrease with loss of hardiness
and resumption of growth. To determine if the same dehydrins are
induced by drought and cold stress in blueberry, dehydrin levels
were examined in roots, stems, and leaves in response to drought
and cold treatment in cultivars with different tolerances to
these stresses. Results indicated that the same three major
dehydrins were induced by drought and cold stress but at
different levels in different organs. Dehydrins were induced to
the highest levels in flower buds with cold stress. Dehydrins
were induced to higher levels in cold hardy and drought tolerant
cultivars than in cold and drought sensitive cultivars. Although
direct evidence for the role of dehydrins in drought and cold
tolerance in blueberry has yet to be established, their unique
expression patterns make them good candidates for scientists to
test for these functions.

Technical Abstract: Previously three dehydrins of 65, 60, and 14 kilodaltons were
identified as the predominant proteins present in cold acclimated
blueberry floral buds. Levels were shown to increase with cold
acclimation and decrease with deacclimation and resumption of
growth. Dehydrins are a group of heat-stable, glycine-rich plant
proteins induced by environmental stimuli which have a
dehydration component including drought, low temperature,
salinity, and seed maturation. In the present study, expression
of blueberry dehydrins was examined in two cultivars in response
to each drought and low temperature treatment to determine if the
same dehydrins are induced by both types of stress. Cultivars
had different tolerances to drought and cold stress. During 34
days of drought stress, relative shoot water content dropped to
51 to 90%, depending upon cultivar. For cold stress experiments,
cultivars with different chilling requirements and levels of cold
hardiness were kept at 4C for five weeks. Dehydrin protein
levels were monitored in response to drought and cold treatments
in roots, stems, and leaves. Results indicated that the same
dehydrins were induced by drought and cold stress but at
different levels. Dehydrins were induced to higher levels in
cold hardy and drought tolerant cultivars than in cold and
drought sensitive cultivars. Although direct evidence for the
role of dehydrins in dehydration tolerance in blueberry has yet
to be established, their unique expression patterns make them
good candidates for this function.