番茄发育相关基因SlLNG1和SlLNG2的鉴定与组织表达模式分析

Identification and Tissue Expression Pattern Analysis of Development Related Genes SlLNG1 and SlLNG2 in Tomato

LNG(LONGIFOLIA)基因在模式植物叶片和果实生长发育过程中发挥重要的调控作用。然而,茄科作物中的LNG基因功能尚不明确。本研究运用同源克隆的方法从"Micro-Tom"番茄矮化品种中鉴定到两个LNG基因,基于其与拟南芥AtLNG1和AtLNG2的序列相似性,命名为SlLNG1和SlLNG2。并对这两个家族成员进行了基因结构、蛋白特征、序列保守结构域和进化关系等分析。结果表明:SlLNG1和SlLNG2分别位于第2染色体和第3染色体,编码产物与马铃薯同源蛋白的相似性最高。荧光定量PCR实验结果发现,SlLNG1和SlLNG2基因在番茄的各组织中的表达具有较大差异,表现出明显的组织特异性。SlLNG1在花中的表达量最高,而SlLNG2在叶片中的表达最高。此外,在SlLNG1和SlLNG2的1.5 kb启动子区域发现多个光响应、胁迫响应和水杨酸响应的顺式作用元件。本研究为深入研究番茄LNG基因的结构、功能和调控机制奠定了基础。

LNG（LONGIFOLIA） genes in model plants are playing important regulatory role in the growth and developmental processes of leaf and fruit. However, the function of LNG genes in Solanaceous crops remains elusive.In this research we identified two LNG genes from the drawfism tomato genotype Solanum lycopersicum cv MicroTom by using a homology-based approach. They were named SlLNG1 and SlLNG2 according to their sequence similarity with AtLNG1 and AtLNG2 in Arabidopsis genome. Further, we analyzed their gene structures, protein features, conserved domains and phylogenetic relationship. The results showed that SlLNG1 and SlLNG2 were located on chromosome 2 and 3, respectively. The coding product displayed the highest similarity with the homologs in potato genome. Quantitative real-time PCR（q PCR） experiments showed that the expression of SlLNG1 and SlLNG2 had great variance between different tissues of tomato plants and displayed strong tissue-specificity. SlLNG1 had higher expression in flower, however, the highest expression of SlLNG2 was observed in leaf. In addition, several cis-acting elements responsive to light, stress and salicylic acid stimuli were found in 1.5 kb regions of SlLNG1 and SlLNG2 promoters. Our study laid a solid foundation for further understanding of the structure, function and regulatory mechanism of tomato LNG genes.