Abstract

Frost resistant mutants of Brassica oleracea var. botrytis were investigated for the presence of CBF/DREB1 and COR15a gene products and induced frost resistance. Total RNA of clones was isolated after 3 h, 6 h, 24 h and 14 d acclimation at 4 °C and proteins and free proline were isolated after 14 d acclimation. cDNA was produced using RT-PCR and the first CBF gene in B. oleracea detected and did quantify. Through SDS-PAGE and Western blotting, the COR15a protein was detected for the first time in B. oleracea. The results confirmed the first report of the presence of BoCBF/DREB1 in B. oleracea and this only appeared under cold acclimation. The sequence analysis of predicted amino acids revealed a very high homology (90%) with CBF sequences of other Brassica species (BnCBF5/DREB1, BrDREB1 and BjDREB1B) and homology reduced to 67% when compared to plants other than Brassicas. BoCBF/DREB1 transcript levels increased up to 24 h acclimation and then declined. Some mutants showed BoCBF/DREB1 expression at 3 h while others only after 6 h and 24 h acclimation. The genotypes showed positive significant correlation between BoCBF/DREB1 expression and frost resistance (R(2) = 0.9343). The proline level under acclimation increased about 8 fold and demonstrated positive and significant correlation with BoCBF/DREB1 expression. Proline also showed positive and significant correlation with frost resistance under cold acclimation but very not under non-acclimation. All clones were positive for COR15a protein after 14 d cold acclimation and expression correlated with frost resistance. Under non-acclimation COR15a was constitutively expressed in 3 mutants.

DOI

10.1016/j.plaphy.2011.08.013

Publication Date

2011-11-01

Publication Title

Plant Physiology and Biochemistry

Volume

49

Issue

11

Publisher

Elsevier BV

ISSN

0981-9428

Embargo Period

2024-11-22

First Page

1323

Last Page

1332

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