大豆孢囊线虫4号生理小种侵染大豆根系诱导表达的cDNA分析

大豆孢囊线虫(Heterodera glycines Ichinohe；Soybean Cyst Nematode，SCN)是一种土传的专性内寄生线虫。SCN的二龄幼虫侵入到大豆幼嫩的根组织中，导致大豆根内的细胞变形并与之形成“合胞体”。合胞体在形态上和生理上的变化是SCN直接诱导大豆基因表达的结果。本研究以高抗SCN的灰布支黑豆为材料，用大豆孢囊线虫二龄幼虫直接接种大豆的根系，应用DDRT—PCR技术及RDB(Reversedot—blotting)杂交鉴定，获得6个阳性cDNA克隆，分别是SCN侵染后5天的A32克隆(GenBank登录号为B1173978)；侵染后10天的B12克隆(GenBank登录号为B1173979)、B71克隆(GenBank登录号为B1173980)；侵染后15天的Cll克隆(GenBank登录号为B1173981)、CPl2(GenBank登录号为B1173982)克隆和CP32克隆(GenBank登录号为B1173983)。序列的同源比较表明，6个cDNA均与Shoemaker构建的大豆基因表达库中的cDNA序列有非常高的同源性，证明这些cDNA是大豆基因表达的产物。其中A32克隆的序列与控制拟南芥下胚轴生长的MYB转录因子、营养元素缺失诱导的番茄根的表达文库中的一个cDNA及番茄抗假单胞杆菌表达文库中的一个cDNA有较高的同源性。

Express Analysis of cDNA Induced by Infecting Roots of Soybean Cyst Nematode Race 4 in Soybean ZZD2315

Soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is one kind of soil sedentary endoparasitic nematodes and one of the most important parasites of soybean. The second-stage juvenile (J2) of SCN penetrates soybean roots and causes the formation of specialized feeding cells which are usually called syncytium in the roots' vascular system. The morphological and physiological changes of syncytium are considered to be the results of soybean gene expression induced by SCN directly. However, the mechanism of those changes are still not very clear, identifying and characterizing resistant gene is very important to make clear the interaction between SCN and soybean. ZDD2315, a local germplasm of Shanxi province, is strong resistance to SCN race 4 and was used in this research. 2-day-old soybean seedlings were inoculated by J2 of SCN race 4. mRNA Differential display was used to detect host gene expression changes during interaction between soybean and SCN. Thirty-six cDNA clones corresponding to mRNAs with different abundances in SCN-infected (19 cDNAs) and uninfected (17 cDNAs) roots were identified. Six of them were recovered as plasmid clones that showed hybridization intensity differences in reverse dot-blotting assay. They are A32 clone (BI173978) from soybean roots five days after inoculation, B12 clone (BI173979) and B71 clone(BI173980) from soybean roots ten days after inoculation, C11 clone (BI173981), CP12 clone (BI173982) and CP32 clone (BI173983)from soybean roots fifteen days after inoculation. The sequence of above six clones have been registered in GenBank. Accession numbers are showed in the brackets. The sequences of six clones were subjected to database comparisons with the aid of BLAST algorithm. All of them showed strong similarity to cDNAs which were in soybean EST library constructed by Shoemaker. Especially, A32 clone showed strong similarity to EST cDNA for coding MYB of Arabidopsis late elongated hypocityl protein, one of cDNA from the library induced by tomato root nutrition deficiency and tomato cDNA of pseudomonas resistance expression library.