Expression of a dehydrin gene during embryo development and drought stress in ABA-deficient mutants of sunflower (Helianthus annuus L.)

• Published in: Plant molecular biology Vol. 39; no. 4; pp. 739 - 748
• Main Authors: Giordani, T, Natali, L, D'Ercole, A, Pugliesi, C, Fambrini, M, Vernieri, P, Vitagliano, C, Cavallini, A
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01-03-1999
• Subjects: Abscisic acid; Abscisic Acid - genetics; Abscisic Acid - metabolism; Accumulation; Disasters; DNA, Complementary; Drought; Embryonic growth stage; Embryos; Gene Expression Regulation, Developmental; Gene Expression Regulation, Plant; Genotype; Genotypes; Helianthus - genetics; Helianthus - growth & development; Helianthus annuus; Molecular Sequence Data; Plant Leaves; Plant Proteins - biosynthesis; Plant Proteins - genetics; Reverse Transcriptase Polymerase Chain Reaction; Seeds - physiology
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1023/A:1006194720022

The synthesis of a particular class of proteins, the dehydrins, is a common response to drought in plants. Dehydrins are known to be synthesized by the cell in response to abscisic acid, which represents a link between environment and nuclear activity, though dehydrin genes may be expressed even constitutively. We have investigated the relationship between abscisic acid (ABA) and accumulation of a dehydrin mRNA in sunflower, in which a dehydrin cDNA (HaDhnla) was isolated. In particular, we studied changes in the steady-state level of dehydrin transcripts in two mutants for ABA synthesis and accumulation: nd-1 (an albino, non-dormant and lethal mutant with a very low ABA content and no ABA accumulation in response to stress) and w-1 (a wilty mutant, with reduced ABA accumulation) during embryo and plantlet development and drought stress. Differences between genotypes were observed through embryogenesis: w-1 shows a lower content of dehydrin transcripts in the early stages compared to control plants, indicating that ABA affects dehydrin mRNA accumulation; however, dehydrin transcripts level appears independent of ABA content in late embryogenesis. Also during drought stress in w-1 adult leaves, ABA is not quantitatively related to the steady-state level of the HaDhn1a transcripts. Finally, data on nd-1 mutant show a high level of dehydrin transcripts after drought stress in plantlet cotyledons and leaflets. These results indicate the existence of two regulation pathways of HaDhn1a transcripts accumulation, an ABA-dependent and an ABA-independent one, which may have cumulative effects.