Cloning and functional analysis of two GmDeg genes in soybean [Glycine max (L.) Merr.]

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• 作者：Xing Kong ; Jingyao Zhang ; Deyue Yu ; Junyi Gai ; Shouping Yang
• 关键词：Cloning ; Deg genes ; Functional analysis ; Photoinhibition ; Soybean [Glycine max (L.) Merr.]
• 刊名：Journal of Plant Biology
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：60
• 期：1
• 页码：48-56
• 全文大小：
• 刊物主题：Plant Sciences; Plant Breeding/Biotechnology; Plant Genetics & Genomics; Plant Systematics/Taxonomy/Biogeography; Plant Ecology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1867-0725
• 卷排序：60

文摘

Although light is the ultimate substrate in photosynthesis, strong light can also be harmful and lead to photoinhibition. The DEG proteases play important roles in the degradation of misfolded and damaged proteins. In this study, two photoinhibition-related genes from soybean [Glycine max (L.) Merr.], GmDeg1 and GmDeg2, were cloned. Bioinformatics analysis indicated that these two proteases both contain a PDZ domain and are serine proteases. The expression levels of GmDeg1 and GmDeg2 increased significantly after 12 h of photooxidation treatment, indicating that GmDeg1 and GmDeg2 might play protective roles under strong light conditions. In in vitro proteolytic degradation assays, recombinant GmDeg1 and GmDeg2 demonstrated biological activities at temperatures ranging from 20°C to 60°C and at pH 5.0 to 8.0. By contrast, the proteases showed no proteolytic effect in the presence of a serine protease inhibitor. Taken together, these results provided strong evidence that GmDeg1 and GmDeg2 are serine proteases that could degrade the model substrate in vitro, indicating that they might degrade damaged D1 protein and other mis-folded proteins in vivo. Furthermore, GmDeg1 and GmDeg2 were transformed into Arabidopsis thaliana to obtain transgenic plants. Leaves from the transgenic and wild-type plants were subjected to strong light conditions in vitro, and the PSII photochemical efficiency (Fv/Fm) was measured. The Fv/Fm of the transgenic plants was significantly higher than that of the wild-type plants at most time points. These results imply that GmDeg1 and GmDeg2 would have similar functions to Arabidopsis AtDeg1, thus accelerating the recovery of PSII photochemical efficiency.