Genome-wide analysis of expression quantitative trait loci(eQTLs)reveals the regulatory architecture of gene expression variation in the storage roots of sweet potato

Dissecting the genetic regulation of gene expression is critical for understanding phenotypic variation and species evolution.However,our understanding of the transcriptional variability in sweet potato remains limited.Here,we analyzed two publicly available datasets to explore the landscape of transcriptomic variations and its genetic basis in the storage roots of sweet potato.The comprehensive analysis identified a total of 724,438 high-confidence single nucleotide polymorphisms(SNPs)and 26,026 expressed genes.Expression quantitative trait locus(eQTL)analysis revealed 4408 eQTLs regulating the expression of 3646 genes,including 2261 local eQTLs and 2147 distant eQTLs.Two distant eQTL hotspots were found with target genes significantly enriched in specific functional classifications.By combining the information from regulatory network analyses,eQTLs and association mapping,we found that IbMYB1-2 acts as a master regulator and is the major gene responsible for the activation of anthocyanin biosynthesis in the storage roots of sweet potato.Our study provides the first insight into the genetic architecture of genome-wide expression variation in sweet potato and can be used to investigate the potential effects of genetic variants on key agronomic traits in sweet potato.

Pesticides Could Alleviate the Symptoms of Sweet Potato Virus Disease(SPVD)

In recent years, sweet potato virus disease （SPVD） has severely affected the production of sweet potato in China. In order to select chemical agents to prevent sweet potato from being infected with SPVD, 14 pesticides were sprayed on the plants of sweet potato infected with SPVD, and the relative mRNA level of the viruses in the leaves and physiological indicators of sweet potato plants were detected. The results showed that after the application of most of the pesticides, the relative mRNA level of the two viruses that caused SPVD decreased, and the chlorophyll content and biomass of sweet potato infected with SPVD increased significantly or extremely significantly. Among the pesticides, BASF virus liquid, 0.1% physcion and Aolike powder for cucumber virus were proved to be the best, as the chlorophyll content and stem length of sweet potato increased significantly. The experiment indicated that the pesticides could reduce the harm of SPVD to sweet potato.

Present Situation and Prospect of Grub Control in Sweet Potato Field

Grub is one of the major pests affecting yield and quality of sweet potato. Although traditional chemical pesticides have quick effect, the disadvantages of high toxicity, strong pest resistance, and heavy pollution hinder the development of modern ecological agriculture, while physical means such as light trapping, sex pheromone method and biological control methods are more safe and lasting compared with chemical means. To provide reference and guidance for grub control and sweet potato production, the control methods against sweet potato grubs are comprehensively explored, and strategy and prospects of using biological technology to control pests are analyzed.

Breeding and Cultivation Techniques for New Edible Orange-Fleshed Sweet Potato Variety Nanshu 012

The carotenoid in sweet potato has a high health value for the human body,and Harvest Plus has also carried out the breeding to improve the nutritional quality of sweet potatoes in order to address the health problems of people nutrient-deficient areas.Nanshu 012 is a new high-quality orange-fleshed sweet potato variety rich in carotenoid,bred by Nanchong Academy of Agricultural Sciences from the " Boga × Sanheshu" hybrid.In the regional test of sweet potato varieties in Sichuan Province during 2009-2010,the average fresh potato yield was 24600 kg/ha,the average dry matter percentage was 29.0 % and the average preserved sweet potato yield was 7152.0 kg/ha;in the production test,the average fresh potato yield was 28410.0 kg/ha and the average preserved sweet potato yield was 8734.5 kg/ha.The multi-point sampling analysis showed that the total sugar content of fresh potato was 5.28 %,protein content was 1.43 %,vitamin C content was 28.9 mg/100 g and carotenoid content was 5.21 mg/100 g.This variety was identified by Sichuan Crop Variety Approval Committee in March 2012,with high fresh potato yield,sweetness,rich carotenoid and resistance to black spot.It is an orange-fleshed sweet potato variety suitable for eating and food processing,and it should be planted in the plot with moderate fertility or above,and should be planted and harvested as early as possible.

Ipomoea batatas HKT1 transporter homolog mediates K^+ and Na^+ uptake in Saccharomyces cerevisiae

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 NaCI 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 NaCI 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 NaCI. Moreover, Na^＋ uptake significantly increased in yeast overexpressing IbHKTI. 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.