There is more to tomato fruit colour than candidate carotenoid genes
There is more to tomato fruit colour than candidate carotenoid genes
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DOI：
10.1046/j.1467-7652.2003.00018.x
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发表时间：
2003-05-01
影响因子：
13.8
通讯作者：
Zamir, D
中科院分区：
文献类型：
--
作者：
Liu, YS;Gur, A;Zamir, D
确定导致复杂表型的基因序列一直是现代生物学的一个主要目标。候选基因方法试图通过定位分析，将在所测表型中具有已知功能作用的序列与负责所研究变异的数量性状位点（QTL）联系起来。为了探索复杂性状候选方法的潜力，我们对番茄果实的红色强度（主要是番茄红素）和与已被充分表征的类胡萝卜素生物合成途径相关的探针进行了QTL定位分析。75个番茄渗入系（ILs），每一个都包含一个纯合的rflp定义的染色体片段，从绿色果实物种Lycopersicon pennellii中划分了107个标记定义的定位箱。其中三个箱子解决了已知的黄色(r)和橙色（B和Del）果实的定性颜色突变，这种突变是由特定类胡萝卜素生物合成基因的变异引起的。根据在不同环境下的试验，将16种改变成熟水果红色强度的OR分配到箱子中。与类胡萝卜素生物合成途径相关的候选序列被定位到23个位点。只有5个QTL与含有候选基因的相同箱子共分离——这个数字完全是偶然的。此外，一个QTL和一个候选QTL相似的图谱位置远不是一个基因和表型之间的直接因果关系。该研究突出了番茄属变异的丰富性和复杂性，可用于番茄果实颜色的基础研究和遗传改良。
Determining gene sequences responsible for complex phenotypes has remained a major objective in modern biology. The candidate gene approach is attempting to link, through mapping analysis, sequences that have a known functional role in the measured phenotype with quantitative trait loci (QTL) that are responsible for the studied variation. To explore the potential of the candidate approach for complex traits we conducted a mapping analysis of QTL for the intensity of the red colour of the tomato fruit (mainly lycopene) and for probes associated with the well-characterized carotenoid biosynthesis pathway. Seventy-five tomato introgression lines (ILs), each containing a single homozygous RFLP-defined chromosome segment from the green-fruited species Lycopersicon pennellii delimited 107 marker-defined mapping bins. Three of the bins resolved known qualitative colour mutations for yellow (r) and orange (B and Del) fruits resulting from variation in specific carotenoid biosynthesis genes. Based on trials in different environments, 16 OR that modified the intensity of the red colour of ripe fruit were assigned to bins. Candidate sequences associated with the carotenoid biosynthesis pathway were mapped to 23 loci. Only five of the QTL co-segregated with the same bins that contained candidate genes - a number that is expected by chance alone. Furthermore, similar map location of a QTL and a candidate is far from a direct causative relationship between a gene and a phenotype. This study highlights the wealth and complexity of the variation present in the genus Lycopersicon that could be employed for basic research and genetic improvement of fruit colour in tomato.