Identification and expression of different dehydrin subclasses involved in the drought response of Trifolium repens.
Reverse transcribed RNAs coding for YnKn, YnSKn, SKn, and KS dehydrin types in drought-stressed white clover (Trifolium repens) were identified and characterized. The nucleotide analyses revealed the complex nature of dehydrin-coding sequences, often featured with alternative start and stop codons within the open reading frames, which could be a prerequisite for high variability among the transcripts originating from a single gene. For some dehydrin sequences, the existence of natural antisense transcripts was predicted. The differential distribution of dehydrin homologues in roots and leaves from a single white clover stolon under normal and drought conditions was evaluated by semi-quantitative RT-PCR and immunoblots with antibodies against the conserved K-, Y- and S-segments. The data suggest that different dehydrin classes have distinct roles in the drought stress response and vegetative development, demonstrating some specific characteristic features. Substantial levels of YSK-type proteins with different molecular weights were immunodetected in the non-stressed developing leaves. The acidic SK2 and KS dehydrin transcripts exhibited some developmental gradient in leaves. A strong increase of YK transcripts was documented in the fully expanded leaves and roots of drought-stressed individuals. The immunodetected drought-induced signals imply that Y- and K-segment containing dehydrins could be the major inducible Late Embryogenesis Abundant class 2 proteins (LEA 2) that accumulate predominantly under drought.
Institute of Plant Sciences and Oeschger Centre for Climate Change Research (OCCR), University of Bern, Altenbergrain 21, 3013 Bern, Switzerland; Plant Stress Molecular Biology Department, Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria. Electronic address: irina.vaseva@abv.bg.
Irina Ivanova
II
Vaseva
Institute of Plant Sciences and Oeschger Centre for Climate Change Research (OCCR), University of Bern, Altenbergrain 21, 3013 Bern, Switzerland.
Iwona
I
Anders
Institute of Plant Sciences and Oeschger Centre for Climate Change Research (OCCR), University of Bern, Altenbergrain 21, 3013 Bern, Switzerland.
Urs
U
Feller
D055864:Droughts; D018506:Gene Expression Regulation, Plant; D018515:Plant Leaves / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D029921:Trifolium / Q000235:genetics* / Q000378:metabolism*
D010940:Plant Proteins; C070556:dehydrin proteins, plant
Dehydrins; Drought; Immunoblot; Splice variants; Trifolium repens