Apple fruit acidity is genetically diversified by natural variations in three hierarchical epistatic genes: MdSAUR37, MdPP2CH and MdALMTII
Apple fruit acidity is genetically diversified by natural variations in three hierarchical epistatic genes: MdSAUR37, MdPP2CH and MdALMTII
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DOI：
10.1111/tpj.13957
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发表时间：
2018-08-01
期刊：
影响因子：
7.2
通讯作者：
Han, Zhenhai
中科院分区：
文献类型：
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作者：
Jia, Dongjie;Shen, Fei;Han, Zhenhai
为了便于在植物中进行实用的标记辅助选择(MAS)，人们已经做出了许多努力来定位数量性状基因座(QTL)。在本研究中，我们利用MapQTL和BSA-seq(基于下一代测序的批量分离分析)对两个独立的系谱群体进行了分析，发现了影响苹果果实酸度的四个主效QTL。在主要的QTL区域筛选了候选基因，并验证了影响苹果果实苹果酸含量的3个功能基因标记，即MdPP2CH编码区的非同义A/G单核苷酸多态(SNP)、MdSAUR37启动子的36bp插入和MdALMTII的SNP。此外，MdPP2CH通过去磷酸化使3个液泡型H+-ATPase(MdVHA-A3、MdVHA-B2和MdVHA-D2)和1个铝激活的苹果酸转运体(MdALMTII)失活，对果实苹果酸积累产生负面影响。MdSAUR37抑制了MdPP2CH的脱磷酸酶活性，表明存在较高层次的遗传互作。因此，MdSAUR37/MdPP2CH/MdALMTII链通过层级上位性遗传效应来精确测定苹果果实的苹果酸含量。主QTL(qtl08.1)MdMYB44启动子区域的A/G SNP(-1010)与果实苹果酸含量密切相关。预测表型值(PPVs)是利用基因标记的初步基因型值估计的，PPVs与观察表型值显著相关。我们的发现为苹果基于植物基因组的选择提供了洞察力，并将有助于进行研究，以了解数量遗传学的基本生理基础。
Many efforts have been made to map quantitative trait loci (QTLs) to facilitate practical marker-assisted selection (MAS) in plants. In the present study, using MapQTL and BSA-seq (bulk segregant analysis using next generation sequencing) with two independent pedigree-based populations, we identified four major genome-wide QTLs responsible for apple fruit acidity. Candidate genes were screened in major QTL regions, and three functional gene markers, including a non-synonymous A/G single-nucleotide polymorphism (SNP) in the coding region of MdPP2CH, a 36-bp insertion in the promoter of MdSAUR37 and a previously reported SNP in MdALMTII, were validated to influence the malate content of apple fruits. In addition, MdPP2CH inactivated three vacuolar H+-ATPases (MdVHA-A3, MdVHA-B2 and MdVHA-D2) and one aluminium-activated malate transporter (MdALMTII) via dephosphorylation and negatively influenced fruit malate accumulation. The dephosphotase activity of MdPP2CH was suppressed by MdSAUR37, which implied a higher hierarchy of genetic interaction. Therefore, the MdSAUR37/MdPP2CH/MdALMTII chain cascaded hierarchical epistatic genetic effects to precisely determine apple fruit malate content. An A/G SNP (-1010) on the MdMYB44 promoter region from a major QTL (qtl08.1) was closely associated with fruit malate content. The predicted phenotype values (PPVs) were estimated using the tentative genotype values of the gene markers, and the PPVs were significantly correlated with the observed phenotype values. Our findings provide an insight into plant genome-based selection in apples and will aid in conducting research to understand the fundamental physiological basis of quantitative genetics.