油茶ALMT基因的克隆及低磷胁迫下的表达分析

Cloning of Aluminum-activated Malate Transporter in Camellia oleifera,Expression Analysis under Low Phosphate Stress

本研究以油茶品种‘长林4号’无性系扦插苗为材料,采用RT-PCR技术分离出一个油茶铝激活苹果酸转运体基因。该基因的c DNA全长1 761 bp,编码586个氨基酸,分子量为65.59 k D,理论等电点(PI)为6.27。与其他植物的ALMT蛋白高度同源,将该基因命名为CoALMT(Gen Bank登录号:KT932706)。CoALMT蛋白含有6个跨膜区,可能定位在细胞质膜上。CoALMT蛋白二级结构中α-螺旋(Alpha helix)、β折叠(Extended strand)、β转角(Beta turn)、无规则卷曲(Random coil)分别占52.05%、16.89%、8.70%、22.35%。以‘长林4号’和‘长林166号’无性系扦插苗为材料,利用qRT-PCR技术分析了沙培条件下两个不同无性系在不同磷水平下不同器官组织中CoALMT基因的表达。结果表明,低磷处理下,两个无性系油茶根系CoALMT的表达量均上升,说明油茶根系中CoALMT基因的表达受到低磷诱导。茎和叶中的表达模式与根中存在差异。低磷处理下不同组织中,‘长林166号’中CoALMT基因的表达量均比‘长林4号’高。综上结果可知CoALMT基因参与油茶对低磷的响应,其可能会影响油茶的磷吸收与利用效率。

In this study, the cutting seedlings of Camellia oleifera clone‘changlin 4'were used as experimental materials. A full-length c DNA sequence of the Aluminum-activated malate transporter(ALMT) genewasisolated from the cutting seedling root of ‘changlin 4'with the method of RT-PCR. The full-length c DNA of the ALMT gene was1 761 bp in size, encoding a deduced polypeptide of 586 amino acids. The estimated molecular weight of the putative protein was 93.42 k D with theelectric point was 9.47. The deduced protein showed high identity to other plants ALMT proteins, therefore the gene was named as CoALMT(Genbank No. KT932706). The CoALMT protein may contain six transmembrane segments and itlikely located inplasma membrane.In the secondary structure of CoALMT, the Alpha helix, Random coil, extended strand and Beta turn account for 52.05%, 16.89%, 8.70% and22.35% respectively. The cutting seedlings of Camellia oleifera clone‘changlin 4'and‘changlin 166'were used as experimental materials in the Sand cultureexperiment, the expression profiles of CoALMT in different tissues of the two clones(‘changlin 6'and‘changlin 4') under different phosphate level were analyzed by q RT-PCR. The results showed that the expression of CoALMT in the roots of the two clones was increased, which indicated that the expression of CoALMT in the root couldbe induced by P-deficiency. The expression patterns of CoALMT gene in the stem and leaf were different with the root. However, the expression of CoALMT in changlin 6'was higher than‘changlin 4'in the root, stem and leaf whether under low phosphate stress. In conclusion, the CoALMT gene may be associated with adaption to P-deficiency and the phosphate updation and utilization efficiency of Camellia oleifera.