玉米中QM同源基因的克隆及其差异表达分析

利用cDNA-AFLP技术和5'' RACE技术在玉米自交系黄早四Ht2上分离并克隆了QM（编码核糖体蛋白L10）同源基因(命名为ZmQM)。其cDNA全长为967 bp, 开放阅读框为738 bp,。该基因编码245个氨基酸的ZmQM蛋白，分子量为27.78 kD, 等电点(pI)为10.69, 预测含蛋白酶C磷酸化位点、N-酰基化位点和酰胺化等位点。玉米ZmQM蛋白与包括人类等l3个物种QM蛋白的同源性比较发现, 氨基酸序列相似性为66%~92%。RT-PCR分析表明, 在接种玉米大斑病菌(Exserohilum turcicum) 1号小种12 h后, 黄早四Ht2中ZmQM基因表达量较黄早四中明显上调，推测ZmQM基因可能参与黄早四Ht2对玉米大斑病菌1号小种的抗性反应。

Cloning and Differential Expression of QM-Like Protein Homologue from Maize

A full-length QM-like cDNA (designated ZmQM) was cloned from maize (Zea mays L.) leaf tissues using cDNA amplified fragment length polymorphism (cDNA-AFLP) and rapid amplification of cDNA ends (RACE) techniques. The expression of ZmQM was examined in leaves of the Ht2 isogenic lines Huangzaosi and HuangzaosiHt2 carrying gene Ht2 for resistance to northern corn leaf blight after inoculation with race 1 of Exserohilum turcicum (Pass.) Leonard et Suggs. Gene ZmQM contains an open reading frame 738 bp in length, which encodes 245 amino acids with a predicted molecular weight of 27.78 kD and an isoelectric point of 10.69. Scanning PROSITE motifs indicated that the amino acid sequence of ZmQM protein includes a Ribosomal protein Ll0e signature, an N-glycosylation site, four Protein kinase C phosphorylation site, a Casein kinase II phosphorylation site, a Tyrosine kinase phosphorylation site, an N-myristoylation site, and an Amidation site. The nucleotide sequence of ZmQM shared 66–92% identity to QM genes isolated from other species. RT-PCR analysis showed that the expression of gene ZmQM was up-regulated in Huangzaosi Ht2 at 12 h after inoculation with race 1 of E. turcicum compared with that in Huangzaosi. By inference, ZmQM protein may be involved in response of HuangzaosiHt2 to inoculation by E. turcicum race 1.