Ma Changqing, Wang Xu, Yu Mengyuan, Zheng Xiaodong, Sun Zhijuan, Liu Xiaoli, Tian Yike, Wang Caihong
College of Horticulture, Qingdao Agricultural University, Qingdao, China.
Engineering Laboratory of Genetic Improvement of Horticultural Crops of Shandong Province, Qingdao, China.
Front Plant Sci. 2021 Nov 8;12:776816. doi: 10.3389/fpls.2021.776816. eCollection 2021.
Fruit color is one of the most important external qualities of pear () fruits. However, the mechanisms that control russet skin coloration in pear have not been well characterized. Here, we explored the molecular mechanisms that determine the russet skin trait in pear using the F population derived from a cross between russet skin ('Niitaka') and non-russet skin ('Dangshansu') cultivars. Pigment measurements indicated that the lignin content in the skin of the russet pear fruits was greater than that in the non-russet pear skin. Genetic analysis revealed that the phenotype of the russet skin pear is associated with an allele of the gene. Using bulked segregant analysis combined with the genome sequencing (BSA-seq), we identified two simple sequence repeat (SSR) marker loci linked with the russet-colored skin trait in pear. Linkage analysis showed that the locus maps to the scaffold NW_008988489.1: 53297-211921 on chromosome 8 in the pear genome. In the mapped region, the expression level of was significantly increased in the russet skin pear and showed a correlation with the increase of lignin content during the ripening period. Genotyping results demonstrated that encoding the transcription factor MYB36 is the causal gene for the russet skin trait in pear. Particularly, a W-box insertion at the promoter of russet skin pears is essential for mediated regulation of lignin accumulation and russet coloration in pear. Overall, these results show that is involved in the regulation of russet skin trait in pear.
果实颜色是梨果实最重要的外在品质之一。然而，控制梨果实锈皮形成的机制尚未得到很好的表征。在此，我们利用由锈皮梨品种（‘新高’）和非锈皮梨品种（‘砀山酥’）杂交产生的F群体，探索了决定梨锈皮性状的分子机制。色素测定表明，锈皮梨果实表皮中的木质素含量高于非锈皮梨表皮。遗传分析表明，锈皮梨的表型与一个基因的等位基因相关。通过结合基因组测序的混合分组分析法（BSA-seq），我们鉴定出两个与梨锈皮性状连锁的简单序列重复（SSR）标记位点。连锁分析表明，该位点定位于梨基因组第8号染色体上的支架NW_008988489.1: 53297-211921处。在定位区域，该基因在锈皮梨中的表达水平显著升高，并且在果实成熟期间与木质素含量的增加呈正相关。基因分型结果表明，编码转录因子MYB36的该基因是梨锈皮性状的因果基因。特别是，锈皮梨该基因启动子处的一个W-盒插入对于介导梨中木质素积累和锈皮形成的调控至关重要。总体而言，这些结果表明该基因参与了梨锈皮性状的调控。
