• 植物保护 •

### 玉米大斑病菌MAPK基因StIME2的基因组定位蛋白质结构预测及表达分析

1. 1河北农业大学真菌毒素与植物分子病理学实验室，中国河北保定 071001
2唐山师范学院生命科学系，中国河北唐山 063000
3伊利诺伊大学香槟分校食品科学与人类营养系，厄本纳 61801，USA
• 收稿日期:2015-02-03 出版日期:2015-07-01 发布日期:2015-07-01
• 通讯作者: 谷守芹，E-mail：gushouqin@126.com；韩建民，E-mail：hanjmnd@163.com；董金皋，E-mail：dongjingao@126.com
• 作者简介:巩校东，E-mail：gxdjy123@gmail.com；王玥，E-mail：597646928@qq.com。巩校东与王玥为同等贡献作者。
• 基金资助:
国家自然科学基金（31171805，31271997，31371897）、河北省自然科学基金（C2012204033，C2013204061）、河北省高等学校科学技术研究项目（ZD20131009）

### Analysis of the Genomic Location, Protein Structure Prediction and Expression of MAPK Gene StIME2 in Setosphaeria turcica

GONG Xiao-dong1, WANG Yue1, ZHANG Pan1,FAN Yong-shan2, GU Shou-qin1, 3, HAN Jian-min1, DONG Jin-gao1

1. 1Mycotoxin and Molecular Plant Pathology Laboratory, Agricultural University of Hebei, Baoding 071001, Hebei, China
2Department of Life Sciences, Tangshan Normal University, Tangshan 063000, Hebei, China
3Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana 61801, USA
• Received:2015-02-03 Online:2015-07-01 Published:2015-07-01

Abstract: 【Objective】The objectives of this study are to determine the location in genome, investigate the protein structure of StIME2 of Setosphaeria turcica, and to compare the expression level of StIME2 at different developmental stages and under different stress conditions, such as temperature, oxygen stress, hyperosmolar stress, hence laying a foundation for future studying functions of StIME2.【Method】 Blast search tool was used to determine the exact location of StIME2 in genome of S. turcica. Physical and chemical properties of StIme2 was analyzed by employing online software ProtParam, and secondary structure of StIme2 was predicted by applying Software SOMPA. Three-dimensional structure of StIme2 was doped out using PHYRE2 server and the structure model was evaluated using online software SAVES and the aim was to obtain Laplace image (Ramachandran Plot). StIME2 expression level was detected at different developmental stages and stress conditions based on semi-quantitative RT-PCR analysis. 【Result】The identity of StIME2 was 98 105, located between 1 560 184 and 1 562 574 in the positive-strand of scaffold_7 in the genome of S. turcica. StIme2 shared characteristic conserved domains of MAPK-like protein kinase, α-helices and random coils, which were its main elements of secondary structure of StIme2. β strands were less and mainly located in N-terminal in this structure. Three-dimensional structure of the protein was composed of a smaller N-terminal and a bigger C-terminal. The expression level of StIME2 was the highest in conidium developmental periods, and was the lowest during appressorium development stage. Under different stress conditions, the expression level of StIME2 appeared the highest when the incubation temperature was at 28℃. In hyperosmotic stress conditions, the expression level of StIME2 increased with the increase of NaCl concentration, but the expression level of the gene was almost completely inhibited at higher stress conditions (0.8 mol·L-1 NaCl). Under oxygen stress conditions, in H2O2 stress treatment, the expression level of StIME2 was heightened with the increase of the concentration of H2O2. And the expression level of the gene was the highest under 10 mmol·L-1 H2O2. 【Conclusion】 StIME2 was located between 1 560 184 and 1 562 574 in the positive-strand of scaffold_7 in the genome of S. turcica. The characteristics of StIme2 were analyzed, and the result showed that StIme2 shared all conserved domains of MAPK kinase of plant pathogenic fungi. However, unlike three types of MAPK genes, which were widely reported in plant pathogens, StIme2 was rarely reported. The expression level of StIME2 in conidium developmental period in S. turcica was the highest. Thus, the authors speculated that StIME2 could play an important role in regulating the developmental processes in spore of the pathogen. Moreover, the expression level of StIME2 changed with the temperature and the highest expression level was at 28℃. The gene may be also involved in osmotic stress and oxygen stress reaction of the pathogen.