Cheng Yunqing, Jiang Siqi, Zhang Xingzheng, He Hongli, Liu Jianfeng
Jilin Provincial Key Laboratory of Plant Resource Science and Green Production, Jilin Normal University, Siping, China.
Front Plant Sci. 2019 Nov 13;10:1465. doi: 10.3389/fpls.2019.01465. eCollection 2019.
Yield loss in the economically important hazelnut ( spp.) occurs through the frequent formation of blank nuts. Although the condition is associated with embryo abortion, we have not yet identified the regulatory genes involved. Therefore, this study aimed to determine the genes related to embryo abortion in hazel. We performed whole-genome re-sequencing and single-nucleotide polymorphism (SNP) analysis on four mutant hazelnut trees (Empty1 to Empty4, ) bearing blank nuts and four wild-type trees (Full1 to Full4, ). A paired comparison of Empty1 vs. Full1, Empty2 vs. Full2, Empty3 vs. Full3, and Empty4 vs. Full4, along with the intersection of Empty1 to Empty4, revealed 3 081 common SNPs in the four blank-nut mutants. Of these, 215 synonymous SNPs in exonic regions were distributed across 178 candidate genes. Heterozygosity analysis showed that average homozygous and heterozygous SNP ratios were respectively 0.409 and 0.591 in the samples. According to Gene Ontology classification, candidate genes were enriched in the categories of binding, catalysis, molecular transducer, transporter, and molecular function regulator. Among these, 18 of 178 genes had homozygous SNPs in Empty1-4. Cis elements in the promoter region of starch synthase 4 (SS4) contain the RY-element, implying seed-specific expression. Starch granules were absent from Empty1-4 cotyledon cells, but abundantly present in Full1-Full4 cotyledon cells. The blank-nut phenotype has heavier nut shells. Overall, we conclude that single-nucleotide variants of (), (), (), (), (), and may induce embryo abortion, leading to blank-nut formation. Our results will benefit future research on how the gain or loss of candidate genes influences seed development. Moreover, our study provides novel prospects for seedless cultivar development.
经济价值重要的榛子（ 属）常因空壳坚果频繁形成而导致产量损失。尽管这种情况与胚胎败育有关，但我们尚未确定其中涉及的调控基因。因此，本研究旨在确定与榛子胚胎败育相关的基因。我们对四棵结空壳坚果的突变榛子树（Empty1至Empty4， ）和四棵野生型树（Full1至Full4， ）进行了全基因组重测序和单核苷酸多态性（SNP）分析。Empty1与Full1、Empty2与Full2、Empty3与Full3以及Empty4与Full4的配对比较，连同Empty1至Empty4的交集，在四个空壳坚果突变体中揭示了3081个常见SNP。其中，外显子区域的215个同义SNP分布在178个候选基因中。杂合性分析表明，样本中平均纯合和杂合SNP比率分别为0.409和0.591。根据基因本体分类，候选基因在结合、催化、分子转导、转运和分子功能调节等类别中富集。其中，178个基因中的18个在Empty1 - 4中有纯合SNP。淀粉合酶4（SS4）启动子区域的顺式元件包含RY元件，暗示种子特异性表达。Empty1 - 4子叶细胞中没有淀粉粒，但Full1 - Full4子叶细胞中大量存在。空壳坚果表型的坚果壳更重。总体而言，我们得出结论， （ ）、 （ ）、 （ ）、 （ ）、 （ ）和 的单核苷酸变体可能诱导胚胎败育，导致空壳坚果形成。我们的结果将有利于未来关于候选基因的增减如何影响种子发育的研究。此外，我们的研究为无籽品种开发提供了新的前景。
