ISHS Acta Horticulturae 812: III International Symposium on Acclimatization and Establishment of Micropropagated Plants
STRESS GENE EXPRESSION MODULATION IN IN VITRO TOMATO PLANTLETS |
| Authors: | J.-F. Dubuc, Y. Desjardins |
| Keywords: | microarray, ex vitro, acclimatization, Solanum lycopersicon, reactive oxygen species, pathogenesis-related protein |
| Abstract:
Many plants species are propagated in vitro worldwide. Unfortunately, a varying percentage of in vitro plantlets suffer high mortality when transferred under natural uncontrolled conditions. Upon transfer to the ex vitro environment, in vitro produced plantlets must undergo major metabolic adjustments and morphological adaptations. The accumulation of ethylene in the vessels, the addition of exogenous sugar and the high ions compositions of the tissue culture medium are all potential sources of stress to in vitro plantlets. Using microarray and real-time quantitative PCR, the impact of in vitro culture conditions on tomato plantlet gene expression was examined. Hence, transcripts from leaf tissue of in vitro and ex vitro tomato plantlets were hybridized on a cDNA microarray to evaluate the differences in expression profiles during both culture stages. After 20 days of growth in vitro, plantlets showed an increased expression of pathogenesis-related (PR) protein and a cellular compartment-specific modulation of reactive oxygen scavenging (ROS) enzymes. A significantly lower transcript level was observed for some protease inhibitors and key genes involved in the octadecanoïd pathway. These data shed light on some of the responses evoked by in vitro culture and more specifically on the specific defense responses induced. This increased knowledge of the in vitro phenotype will help understand the causes of the poor survival of ex vitro plantlets. | |
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