Mathiazhagan Malarvizhi, Elangovan Dayanandhi, Chinnaiyan Vasugi, Shivashankara Kodthalu Seetharamaiah, Sudhakar Rao Darisi Venkata, Ravishankar Kundapura Venkataramana
Division of Basic Sciences, ICAR-Indian Institute of Horticultural Research, Bengaluru, India.
Centre for Post-graduate Studies, Jain (Deemed-to-be) University, Bengaluru, India.
Front Plant Sci. 2024 Feb 27;15:1335715. doi: 10.3389/fpls.2024.1335715. eCollection 2024.
L. is an important fruit crop in the tropical and subtropical regions of the world. The advanced breeding methods are not employed for important commercial traits like peel and pulp color, seed hardiness, fruit size, etc., due to the scarcity of genome-wide molecular markers and high-density linkage maps. In this study, we employed single-nucleotide polymorphism (SNP) markers and identified quantitative trait loci (QTL) regions that are associated with color traits of leaf, peel, and pulp in the guava intervarietal mapping population. The mapping population was developed from the contrasting genotypes of fruit and leaf color. Variations in color among the segregating hybrids were recorded both visually and using a Color reader. A high-density linkage map of guava was constructed using the SNP markers from genotyping by sequencing (GBS) of 150 hybrid individuals of the cross 'Arka Poorna' (green) x 'Purple Local' (purple). The integrated linkage map consisted of 1426 SNPs mapped on 11 linkage groups (LG), spanning a total distance of around 730 cM with an average of 129.6 markers per LG. Through QTL analysis for color traits, a minor QTL region was identified for visually scored leaf color and peel color on LG1, whereas a major QTL was detected for pulp color in LG4. The Hunter color values (L* and, a*) also had major QTLs with overlapping marker intervals for leaf and peel colors, establishing the association of SNP markers to the trait. The QTLs harbored genes and transcription factors involved in lycopene and anthocyanin pigment biosynthesis. This is the first report of a high-density linkage map based on SNP markers in guava and QTL mapping for color characters in leaf, fruit peel and pulp. The genotyping information generated in this study can aid in genetic engineering and marker-assisted breeding in guava.
番石榴是世界热带和亚热带地区一种重要的水果作物。由于全基因组分子标记和高密度连锁图谱的缺乏，先进的育种方法尚未应用于果皮和果肉颜色、种子抗性、果实大小等重要商业性状。在本研究中，我们使用单核苷酸多态性（SNP）标记，在番石榴品种间作图群体中鉴定了与叶片、果皮和果肉颜色性状相关的数量性状位点（QTL）区域。该作图群体由果实和叶片颜色对比鲜明的基因型培育而成。对分离杂种的颜色变化进行了目视记录，并使用颜色读取器进行记录。利用对‘Arka Poorna’（绿色）בPurple Local’（紫色）杂交组合的150个杂种个体进行测序基因分型（GBS）得到的SNP标记，构建了番石榴的高密度连锁图谱。整合的连锁图谱由1426个SNP组成，分布在11个连锁群（LG）上，总跨度约730厘摩，每个LG平均有129.6个标记。通过对颜色性状的QTL分析，在LG1上鉴定出一个与目视评分的叶片颜色和果皮颜色相关的小QTL区域，而在LG4上检测到一个与果肉颜色相关的主QTL。亨特颜色值（L和a）在叶片和果皮颜色上也有主QTL，其标记区间重叠，证实了SNP标记与该性状的关联。这些QTL包含参与番茄红素和花青素色素生物合成的基因和转录因子。这是基于SNP标记的番石榴高密度连锁图谱以及叶片、果皮和果肉颜色性状QTL定位的首次报道。本研究中产生的基因分型信息有助于番石榴的基因工程和标记辅助育种。
