科研之友
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摘要
Drought tolerance in barley is highly correlated with the expression of two genes: Hordeum vulgare aleurone 1 (HVA1) and stress-responsive gene 6 (SRG6). Though their role in the mechanism of drought response in barley has been confirmed in transgenic plants, the regulation pathways of these genes%26apos; expression have not been sufficiently studied, especially on the level of whole plants. We used four barley genotypes of different drought tolerance to establish and compare the expression profiles of SRG6 and HVA1 and to associate them with the possible physiological and biochemical signals of water deficit. Both genes studied were expressed to a greater extent in drought tolerant genotypes. The highest level of HVA1 transcript accumulation was observed under conditions where the leaf water potential decreased significantly. In tolerant genotype this signal was partially replaced with abscisic acid (ABA) signal of soil water deficit and the final transcript accumulation was about 14 times lower than in the case of leaf water deficit. In the case of SRG6 the main signal which can triggered the transcript accumulation was ABA but in the case of tolerant genotype the direct effect of leaf water deficit was also observed. Thus, it seems to be possible that in drought tolerant barley genotypes, HVA1 and SRG6, are not only more expressed during drought, but tolerant genotypes may be also more sensitive to various internal signals confirming environmental water deficit. The putative role of hydrogen peroxide as a signal of water deficit in the regulation of both genes expression was not confirmed. The drought-induced expression of both HVA1 and SRG6 was additionally reduced in the light. Because of this powerful complexity, a true understanding of plant response to drought requires further studies integrating gene expression and cell signaling analysis in single organs or tissues with whole plant physiology and long distance signaling.
- 出版日期2012-11
