Identification of proteins involved in freezing tolerance in Arabidopsis thaliana

CABELLO, JULIETA V.; ARCE, AGUSTÍN L. AND CHAN, RAQUEL L.

Carlos Paz

Congreso; Reunión Anual de la SAIB; 2008

SAIB

Plants normally show a limited freezing tolerance occurring via different transduction signal pathways. Pathogenesis related proteins including chitinases, â-glucanases and thaumatin like proteins as well as cell wall modifying ones are involved in such pathways. A sunflower transcription factor was identified as playing a clue role in the freezing tolerance. This TF was ectopically expressed in Arabidopsis plants and these transformed plants showed a significant tolerance both in chilling and freezing conditions. A microarray analysis was performed with RNA from transgenic plants compared with non transformed ones indicating that several transcripts encoding PR and cell wall modifying proteins are induced in the transgenic genotype. It was reported that these proteins exhibit antifreeze activity in winter rye plants. However, no reports on functional analysis of these proteins, related to antifreeze activity in Arabidopsis, are available. These transgenic plants exhibit morphological and developmental differences with WT ones that are abolished when transgenic plants with the own TF promoter, instead a constitutive one, directing the expression were obtained. Apoplastic proteins differentially expressed in both genotypes were identified after purification. We propose that this transcription factor confers cold tolerance to plants via the induction of proteins able to stop ice growth.