Os05g0530400

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Annotated Information

Function

Please input function information here. A plant is subject to various kinds of environmental stresses, including water, temperature, light, and soil. These stresses can cause various types of physiological damage in plants. Because they cannot move, plants can defend themselves against such stresses only by making metabolic and structural adjustments. To achieve this defense, genes need to be expressed in response to a stress stimulus to induce or suppress the production of specific proteins, such as heat shock proteins (HSPs). Thus, plants develop stress tolerance at the cellular level. Firstly, Spl7 encodes a heat stress transcription factor (HSF) protein. We also discuss the role of Spl7 in making plants tolerant to cell death caused by environmental stresses, such as high temperature. Moreover, an Spl7 mutant plant was susceptible to several pathogens and showed very low expression of the five genes strongly correlated with the onset of defense response. Spl7 lesions could not be readily triggered by mechanical wounding. Thus, the lesion formation of spl7 might not be directly associated with hypersensitive-response cell death. Rather, it seems to be necrosis caused by environmental stresses.

Expression

Please input expression information here. Rice spotted leaf mutant spl7 showed relatively small, reddish brown lesions scattered over the whole surfaces of leaves. . Under natural summer field conditions (maximum temperature 30°Cto35°C), the lesions appeared from the tillering stage and continuously increased to heading time. The density of the lesions decreased in a greenhouse (26°C, solar radiation). When UV rays were intercepted by covering the plants with UV-cut sheet, the density of the lesions also decreased remarkably. On the other hand, no lesions were observed on mutant plants grown in a controlled growth chamber (26°C, artificial light), and a small number of lesions appeared in a high-temperature growth chamber (35°C, artificial light). No lesions appeared on seedlings or young leaves in all conditions above mentioned. These results suggest that the accumulation of stresses, such as high temperature or UV solar radiation, causes lesion development.

Evolution

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You can also add sub-section(s) at will. In adult plants, spl7 mutants formed small, reddish brown necrotic lesions; formation was enhanced by high temperature and suppressed by UV interception. Cells in adult leaves accumulate various stresses but are usually prevented from dying by cell survival factors, e.g., HSPs. Spl7, a rice HSFA4, may control such cell survival factors. HSFs play a central role in the transmission of information regarding environmental stress to the nucleus, where the binding of activated HSFs to heat shock elements in promoters of HSP genes results in the transcriptional induction of the heat stress response. Genes for HSFs have been isolated and characterized from yeast, Drosophila, and some vertebrates. In plants, they have been reported in tomato, Arabidopsis, soybean, maize , and others. All HSF proteins have an evolutionarily conserved core consisting of a DBD and an oligomerization domain, HR-A�B. HSFs are multigene families in both plants and vertebrates. On the basis of phylogeny of DBDs and organization of HRs, plant HSFs can be subdivided into three major classes: A, B, and C. Spl7 seems to be a plant class A HSF. We used three main criteria for the classification: (i) Spl7 has a class A-specific insertion of 21 a residues between HR-A and HR-B. (ii) Spl7 has an NLS located adjacent to the HR-A�B region. In class B HSFs, the NLS is located more distally, close to the C terminus.(iii) Spl7 has an HR-C and an AHA which are absent from class B HSFs. Parsimony analysis of DBDs shows that Spl7 is a class A4 HSF. At present, five HSFs (two from Arabidopsis, one each from tobacco, maize, and have been classified into class A4; of these, At HSF21 and ZmHSFb are heat-inducible, likeSpl7. The biological function of class A4 HSFs in plants remains to be shown.

Labs working on this gene

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  • Institute of the Society for Techno-Innovation of Agriculture, Forestry, and Fisheries, Tsukuba, Ibaraki 305-0854, Japan;

Department of Molecular Genetics,National Institute of Agrobiological Sciences,Tsukuba,Ibaraki 305-8602, Japan; Department of Biology, Faculty of Science, Toyama University,Toyama 930-8555, Japan

References

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Structured Information