Histone modifications and histone variants are of importance in many biological processes. Whether they play some roles in regulating soybean salinity stress response is unknown. Previously, no study of histone modifications and histone variants in soybean were reported. In this study, I elucidated that in soybean leaves, mono-, di- and tri-methylation at Lysine (K) 4, 27 and 36, and acetylation at Lysine 14, 18 and 23 were present in histone H3. Moreover, H3K27 methylation and H3K36 methylation usually excluded each other. Although H3K79 methylation was not reported in Arabidopsis, they were detected in soybean. In soybean histone H4, Lysine 8 and 12 were acetylated. In addition, the variants of histone H3 and H4 and their modifications were also determined. The variants of histone H3 were different at positions of A31F41S87S90 (histone variant H3.1) and T31Y41H87 L90 (histone variant H3.2), respectively. Lysine 4 and 36 methylation were only detected in histone H3.2, suggesting that histone variant H3.2 might associate with actively transcribing genes. The two variants of histone H4 (H4.1 and H4.2) were different at amino acid 60. Moreover, I also found that the abundance of most of the histone modifications and histone variants did not change under the salinity stress except that H3K79 methylation would be up-regulated by the salinity stress. / In a parallel study, a PHD (plant homeodomain) finger domain containing protein, GmPHD1, was able to decipher the 'code' underlying H3K4 methylation. GmPHD1 was ubiquitously expressed in soybean and its expression increased upon salinity stress. GmPHD1 could bind to histone H3K4 methylation, with the preference to H3K4 dimethylation. It could then recruit several proteins, which were GmGNAT1, GmElongin A, and GmISWI. The interaction between GmPHD1 and GmGNAT1 was regulated by the self-acetylation of GmGNAT1. GmGNAT1 could also acetylate histone H3; GmElongin A was a transcription elongation factor; and GmISWI was a chromatin remodeling protein. Our data also indicated that the GmPHD1 located at the promoter of several soybean salt stress inducible genes. Therefore, the GmPHD1 recruited proteins to remodel the chromatin structure and facilitate the transcription of those salt stress inducible genes. Moreover, GmGNAT1 exhibited the preference to acetylate histone H3K14, therefore representing a kind of histone crosstalk between H3K4 methylation and H3K14 acetylation. / Proteomics studies with 2-DE revealed that salt treatment may affect soybean photosynthesis and chloroplast formation. Comparison between the proteomic profiles of salt tolerant soybean variety (wild type) and salt sensitive soybean variety (cultivated, Union) indicated that protein levels in the detoxification and defense pathway as well as energy metabolism were higher in the wild type soybean, while the process of protein metabolism was less active. In addition, proteomic profiles of the cultivated soybean roots at different developmental stages were also compared to identify proteins related to soybean development. The expression of proteins which play critical roles in detoxification and defense pathways were higher at the seedling stage, especially the proteins which regulated the formation of ROS. / Soybean is an important economic crop and its production can be severely affected by salinity stress. At present, the soybean response to salinity stress is not clear. In my studies, I tried to understand this process from the perspective of proteomics and epigenetics, especially histone modifications. / Wu, Tao. / Advisers: Njai Sai Ming; Lam Hon Ming. / Source: Dissertation Abstracts International, Volume: 73-02, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 126-151). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_344715 |
| Date | January 2010 |
| Contributors | Wu, Tao, Chinese University of Hong Kong Graduate School. Division of Life Sciences. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, theses |
| Format | electronic resource, microform, microfiche, 1 online resource (xx, 151 leaves : ill.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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