关键词: 紫薇, 叶色, SNP分子标记, 数据挖掘, 分子标记辅助育种

Abstract:

To identify leaf color-linked SNP markers in crape myrtle cultivars（Lagerstroemia indica），19 crape myrtle cultivars and their F₁ progeny were utilized. This study conducted both eye-based and CIE L^*a^*b^*-based measurements of leaf color during various growth stages（young leaf stage，full leaf stage，full bloom stage，and leaf abscission stage），and integrated transcriptome and genome data with targeted sequencing to identify candidate SNP markers potentially linked to leaf color，and with these SNPs subsequently detected in the F₁ progeny using high-resolution melting curve（HRM）analysis. The results indicated that both eye-based estimation and CIE L^*a^*b^* values could effectively distinguish leaf colors，with the a^* value specifically differentiating green leaves from colored leaves（red and purple-red）. Additionally, significant differences were observed in brightness value L^*，yellowness value b^*，chroma C，and hue angle h among the three types of leaf color. A total of fifty-three candidate SNP sites were obtained through data mining，but targeted sequencing results revealed that only six of them had a ΔSNP greater than 0.2. Sanger sequencing and HRM analysis of the F₁ plants derived from‘Dynamite’and‘Baiyun Yingxia’showed that four SNPs had a correlation coefficient with leaf color ranging from 0.184 to 0.623 reaching a significant level，and one SNP marker exhibited dimorphism between green and colored leaves. The higher the frequency of the purple（red）（P）type genotype，the deeper the leaf color，suggesting that the purple-red leaf color is caused by the additive effect of multiple genes.

Key words: crape myrtle, leaf color, SNP molecular markers, data mining, molecular-assisted breeding