甘薯小象甲是甘薯上危害最为严重的世界性害虫，对生态环境和社会经济遭受巨大损失。为提高甘薯小象甲综合防治的效果和深入理解其遗传进化机制，我们对甘薯小象甲功能基因组学进行了的深入研究。利用 Illumina 和 PacBio技术，对单对交配15代的甘薯小象甲进行测序。获得了甘薯小象甲成虫染色体水平的基因组，基因组大小为338.84Mb，Contig N50 和 Scaffold N50 分别为 14.97 Mb和34.23 Mb。预测重复序列为 157.51 Mb和 11907 个编码蛋白质基因。共有 337.06 Mb长度的基因组序列被定位到 11 条染色体上，其中能够确定顺序和方向的序列长度为 333.79 Mb，占定位到染色体上总序列长度的 99.03 %。比较基因组学分析表明，甘薯小象甲和中欧山松大小蠹亲缘关系较近，约 1.38 亿年前从中欧山松大小蠹的祖先分化而来。许多重要的基因家族在甘薯小象甲基因组中得到了扩张，包括农药解毒、耐冷应激和化学感觉系统相关基因家族。为了进一步解析气味结合蛋白在甘薯小象甲嗅觉识别过程中的作用，竞争性结合分析结果表明，CforOBP4-6对性信息素及其他配体具有很强的结合亲和力。高质量的甘薯小象甲基因组图谱为揭示其分子生态学基础、群体遗传和适应性进化机制及绿色有效防控的新方法和新技术提供了坚实的基础。

Soil salinity causes the negative effects on the growth and yield of crops. In this study, two sweet potato (Ipomoea batatas L.) cultivars, Xushu 28 (X-28) and Okinawa 100 (O-100), were examined under 50 and 100 mmol L^–1 NaCl stress. X-28 cultivar is relatively high salt tolerant than O-100 cultivar. Interestingly, real-time quantitative polymerase chain reaction (RT-qPCR) results indicated that sweet potato high-affinity K⁺ transporter 1 (IbHKT1) gene expression was highly induced by 50 and 100 mmol L^–1 NaCl stress in the stems of X-28 cultivar than in those of O-100 cultivar, but only slightly induced by these stresses in the leaves and fibrous roots in both cultivars. To characterize the function of IbHKT1 transporter, we performed ion-flux analysis in tobacco transient system and yeast complementation. Tobacco transient assay showed that IbHKT1 could uptake sodium (Na⁺). Yeast complementation assay showed that IbHKT1 could take up K⁺ in 50 mmol L^–1 K⁺ medium without the presence of NaCl. Moreover, Na⁺ uptake significantly increased in yeast overexpressing IbHKT1. These results showed that IbHKT1 transporter could have K⁺-Na⁺ symport function in yeast. Therefore, the modes of action of IbHKT1 in transgenic yeast could differ from the mode of action of the other HKT1 transporters in class I. Potentially, IbHKT1 could be used to improve the salt tolerance nature in sweet potato.

The information of single nucleotide polymorphisms (SNPs) is quite unknown in sweetpotato.  In this study, two sweetpotato varieties (Xushu 18 and Xu 781) were sequenced by Illumina technology, as well as de novo transcriptome assembly, functional annotation, and in silico discovery of potential SNP molecular markers.  Tetra-primer Amplification Refractory Mutation System PCR (ARMS-PCR) is a simple and sufficient method for detecting different alleles in SNP locus.  Total 153 sets of ARMS-PCR primers were designed to validate the putative SNPs from sequences.  PCR products from 103 sets of primers were different between Xu 781 and Xushu 18 via agarose gel electrophoresis, and the detection rate was 67.32%.  We obtained the expected results from 32 sets of primers between the two genotypes.  Furthermore, we ascertained the optimal annealing temperature of 32 sets of primers.  These SNPs might be used in genotyping, QTL mapping, or marker-assisted trait selection further in sweetpotato.  To our knowledge, this work was the first study to develop SNP markers in sweetpotato by using tetra-primer ARMS-PCR technique.  This method was a simple, rapid, and useful technique to develop SNP markers, and will provide a potential and preliminary application in discriminating cultivars in sweetpotato.

Sequence-related amplification polymorphism (SRAP) markers closely linked to stem nematode resistance gene were developed in sweetpotato, Ipomoea batatas (L.) Lam. Using bulked segregant analysis (BSA), 200 SRAP primer combinations were screened with the resistant and susceptible bulked DNA from the 196 progenies of an F1 single-cross population of resistant parent Xu 781×susceptible parent Xushu 18, 77 of them showed polymorphic bands between resistant and susceptible DNA. Primer combinations detecting polymorphism between the two bulks were used to screen both parents and 10 individuals from each of the bulks. The results showed that primer combination A9B4 produced 3 specific bands in the resistant plants but not in the susceptible plants, suggesting that the markers, named Nsp1, Nsp2 and Nsp3, respectively, linked to a gene for stem nematode resistance. Primer combination A3B6 also produced a SRAP marker named Nsp4 linking to the resistance gene. Amplified analysis of the 196 F1 individuals indicated that the genetic distance between these markers and the resistance gene was 4.7, 4.7, 6.3, and 9.6 cM, respectively.