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.

Eggplant is one of the most important vegetables worldwide. Prickles on the leaves, stems and fruit calyxes of eggplant may cause difficulties during cultivation, harvesting and transportation, and therefore is an undesirable agronomic trait. However, limited knowledge about molecular mechanisms of prickle morphogenesis has hindered the genetic improvement of eggplant. In this study, we performed the phenotypic characterization and transcriptome analysis on prickly and prickleless eggplant genotypes to understand prickle development at the morphological and molecular levels. Morphological analysis revealed that eggplant prickles were multicellular, lignified and layered organs. Comparative transcriptome analysis identified key pathways and hub genes involved in the cell cycle as well as flavonoid biosynthetic, photosynthetic, and hormone metabolic processes during prickle development. Interestingly, genes associated with flavonoid biosynthesis were up-regulated in developing prickles, and genes associated with photosynthesis were down-regulated in developing and matured prickles. It was also noteworthy that several development-related transcription factors such as bHLH, C2H2, MYB, TCP and WRKY were specifically down- or up-regulated in developing prickles. Furthermore, four genes were found to be differentially expressed within the Pl locus interval. This study provides new insights into the regulatory molecular mechanisms underlying prickle morphogenesis in eggplant, and the genes identified might be exploited in breeding programs to develop prickleless eggplant cultivars.

Three TaLTPs were found to enhance chilling tolerance of transgenic Arabidopsis, which were characterized by analyzes of promoter-GUS activity, subcellular localization, chromosomal location and transcriptional profile. Non-specific lipid transfer proteins (nsLTP) are abundantly expressed in plants, however, their functions are still unclear. In this study, we primarily characterized the functions of 3 type I TaLTP genes that were localized on chromosomes 3A, 3B, and 5D, respectively. The transcripts of TaLTPIb.1 and TaLTPIb.5 were induced under chilling, wound, and drought conditions, while TaLTPId.1 was only up-regulated by dark treatment. All the 3 TaLTP genes could be stimulated by the in vitro treatment of salicylic acid, while TaLTPId.1 was also positively regulated by methyljasmonic acid. Furthermore, the promoter-reporter assay of TaLTPIb.1 in the transgenic brachypodium showed a typical epidermis-specific expression pattern of this gene cluster. When fused with EGFP, all the 3 proteins were shown to localize on the plasma membrane in transgenic tobacco, although a signal in chloroplasts was also observed for TaLTPId.1. Heterogeneous overexpression of each of the TaLTP genes in Arabidopsis resulted in longer root length compared with wild type plants under chilling condition. These results suggest that type I TaLTPs may have a conserved functionality in chilling tolerance by lipid permeation in the plasma membrane of epidermal cells. On the other hand, the type I TaLTPs may exert functional divergence mainly through regulatory subfunctionalization.

Fusarium head blight, caused primarily by Fusarium graminearum, is a destructive disease of wheat throughout the world. However, the mechanisms of host resistance to FHB are still largely unclear. Deoxynivalenol (DON) produced by F. graminearum which enhances the pathogen to spread could be converted into inactive form D3G by UDP-glycosyltransferases (UGTs). A DON responsive UGT gene, designated as TaUGT4, was first cloned from wheat in this study. The putative open reading frame (ORF) of TaUGT4 was 1386 bp, encoding 461 amino acids protein. TaUGT4 was placed on chromosome 2D using a set of nulli-tetrasomic lines of wheat cultivar Chinese Spring (CS). When fused with eGFP at C terminal, TaUGT4 was shown to localize in cytoplasm of the transformed tobacco cells. The transcriptional analysis revealed that TaUGT4 was strongly induced by F. graminearum or DON in both of FHB-resistant cultivar Sumai 3 and susceptible cultivar Kenong 199, especially in Sumai 3 under DON treatment. Similar increase of TaUGT4 expression was observed in Sumai 3 and Kenong 199 in response to salicylic acid (SA) treatment. But interestingly, the transcripts level of TaUGT4 in Sumai 3 showed significantly higher than that in Kenong 199 after treated with methyl jasmonate (MeJA). According to the expression patterns, TaUGT4 might lead to different effects between FHB-resistant genotype and susceptible genotype in the process against F. graminearum inoculation. It had also been discussed in this paper that JA signaling pathway might play a significant role in the resistance against F. graminearum compared to SA signaling pathway.

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In common wheat (Triticum aestivum L.) and its relative species, considerable progress has been made in understanding the structure and function of the high-molecular-weight glutenin subunit (HMW-GS). As a species closely related to wheat, Aegilops umbellulata is an important resource for wheat genetic improvement. In this paper, we report a novel HMW-GS 1Ux3.5 in Aegilops umbellulata Y361. The complete open reading frame (ORF) coding for 1Ux3.5 was cloned and sequenced. Analysis of the deduced amino acid sequence revealed that the primary structure of 1Ux3.5 was similar to those of previously published HMW-GSs. The 1Ux3.5 possessed an extra cysteine residue in the repetitive domain, indicating that the subunit may be related to excellent dough quality. Subsequently, the single proteins of 1Ux3.5 and 1Dx5 (used as positive control) were purified at a scale sufficient for incorporation into flour for a dough quality test. Both the SDS sedimentation volume and mixograph parameters demonstrated that 1Ux3.5 showed a greater contribution to the dough quality than 1Dx5. Therefore, the 1Ux3.5 subunit from Aegilops umbellulata may have potential value in improving the processing properties of hexaploid wheat varieties.