This study investigated the effects of dioscorea opposite waste (DOW) on the growth performance, blood parameters, rumen fermentation and rumen microbiota of weaned lambs.  Sixty healthy weaned Small-Tailed Han lambs (male, (22.68±2.56) kg initially) were used as the experimental animals.  Four levels of concentrate: 0 (control, CON), 10% (DOW1), 15% (DOW2) and 20% (DOW3), were replaced with DOW in the basal diet as experimental treatments.  The results showed that lambs fed the DOW2 diet had a higher (P<0.05) dry matter intake (DMI) than the other groups.  There was no significant difference (P>0.05) among DOW groups in average daily weight gain (ADG), and replacing concentrate with DOW linearly or quadratically increased (P<0.05) the ADG, while lambs fed the DOW2 diet showed greater (P<0.05) ADG than the CON group.  The relative plasma concentration of growth hormone (GH), insulin like growth factor-1 (IGF-1) and insulin were affected by DOW, replacing concentrate with DOW linearly or quadratically (P<0.05) enhanced the plasma concentration of GH, IGF-1 and insulin, which was significantly higher (P<0.05) in the DOW2 group than in the CON, DOW1 and DOW3 groups.  In addition, the DOW treatment showed a lower (P<0.05) concentration of blood urea nitrogen (BUN) than the CON group.  Replacing concentrate with DOW quadratically decreased (P<0.05) the ruminal ammonia nitrogen (NH₃-N) and increased (P<0.05) the total of volatile fatty acids (TVFAs) at 0 and 4 h after feeding as well as linearly decreased (P<0.05) the NH₃-N at 8 h after feeding.  Replacing concentrate with DOW linearly decreased (P<0.05) the propionate and increased the aceate before feeding, and linearly decreased (P<0.05) propionate and quadratically increased (P<0.05) the aceate at 4 and 8 h after feeding.  Lambs fed the DOW2 diet increased the phylum Firmicutes and genera Succiniclasticum and Ruminococcus_1 groups, whereas decreased (P<0.05) the relative abundance of phylum Deferribacteres and genera intestinimonas and Ruminiclostridium.  In summary, replacing the concentrate with 15% DOW was beneficial for improving the rumen fermentation and ADG by increasing the DMI and modulating the rumen microbial community.

Early bacterial colonization and succession within the gastrointestinal tract have been suggested to be crucial in the development of host immunity.  In this study, we have investigated the changes in live weight and concentrations of selected serum parameters in relation to their fecal bacterial communities as determined by high throughput sequencing of the 16S rRNA gene over the same period in lambs.  The results showed that lambs’ growth performance, the serum parameters, fecal bacterial community and fecal bacterial functions were all affected (P<0.05) by age of the lambs.  Similarity within age groups of fecal microbiota was lower in the preweaning period and increased sharply (P<0.05) after weaning at 60 days.  The similarity between the samples collected from birth to 90 days of age and those collected at 120 days of age, increased (P<0.05) sharply after 30 days of age.  Some age-associated changes in microbial genera were correlated with the changes in concentrations of immune indicators, including negative (P<0.05) correlations between the relative abundance of Lachnospiraceae UCG-010, Eubacterium coprostanoligenes group, Ruminococcaceae UCG-005, Ruminococcaceae UCG-009, Ruminococcaceae UCG-013, Ruminiclostridium 6, Ruminococcaceae UCG-008, and Oscillibacter with serum concentrations of lipopolysaccharide (LPS), D-lactate dehydrogenase (DLA), immunoglobulin (IgA, IgM, and IgG), and cytokines (interleukin-1β (IL-1β), IL-6, IL-12, and IL-17), tumor necrosis factor-α (TNF-α), and the relative abundance of these genera increased from 45 days of age.  In conclusion, these results suggested that the age-related abundances of particular genera were correlated with serum markers of immunity in lambs, and there might be a critical window in the period from birth to 45 days of age which provide an opportunity for potential manipulation of the fecal microbial ecosystems to enhance immune function.

Although fungal communities in the gastrointestinal tract have a significant role in animal health and performance, their dynamics within the tract are not well known.  Thus, this study investigated fungal community dynamics in the rumen and rectum of lambs from birth to 4 mon of age by using IT1S rDNA sequencing technology together with the RandomForest approach to determine age-related changes in the fungal ecology.  The results indicated that gastrointestinal fungal community composition, diversity, and abundance altered (P<0.05) with the increasing age of the lambs.  Two phyla, Ascomycota and Basidiomycota, dominated the samples.  Similarity within age groups of the rumen fungi increased sharply after 45 days of age, while the similarity increased (P<0.05) significantly after 60 days of age in the rectum.  The age-related genera, Acremonium, Microascus, Valsonectria, Myrmecridium, Scopulariopsis, Myrothecium, Saccharomyces, and Stephanonectria, were presented in both ruminal and rectal communities, and their changes in relative abundance were consistent at both sites.  The principal coordinates analysis showed significant differences (P<0.05) between the fungal communities in the rumen and rectum.  Our findings demonstrate that both the age of lambs and the gastrointestinal tract region can affect the composition of these fungal communities, and this provides new insight and directions for future studies in this research area.

The peroxisomal matrix oxidase, catalase and peroxidase are imported peroxisomes through the shuttling receptors, which regulates the cellular oxidative homeostasis and function.  Here, we report that PTS1 shuttling receptor FvPex5 is involved in the localization of PTS1, utilization of carbon sources and lipids, elimination ROS, cell wall stress, conidiation, fumonisin B₁ (FB₁) production, and virulence in maize pathogen Fusarium verticillioides.  Significantly, differential expression of PTS1-, PTS2-, PEX- and FB₁ toxin-related genes in wild type and ΔFvpex5 mutant were examined by RNA-Seq analyses and confirmed by RT-PCR assay.  In addition, different expression of PTS1 and PTS2 genes of the ΔFvpex5 mutant were enriched in diverse biochemical pathways, such as carbon metabolism, nitrogen metabolism, lipid metabolism and the oxidation balance by combining GO and KEGG annotations.  Overall, we showed that FvPex5 is involved in the regulation of genes associated with PTS, thereby affecting the oxidation balance, FB₁ and virulence in F. verticillioides.  The results help to clarify the functional divergence of Pex5 orthologs, and may provide a possible target for controlling F. verticillioides infections and FB₁ biosynthesis.

As a critical food crop, sweetpotato (Ipomoea batatas (L.) Lam.) is widely planted all over the world, but it is deeply affected by Sweetpotato Virus Disease (SPVD).  The present study utilized short tandem target mimic (STTM) technology to effectively up-regulate the expression of laccase (IbLACs) by successfully inhibiting the expression of miR397.  The upstream genes in the lignin synthesis pathway were widely up-regulated by feedback regulation, including phenylalanine ammonialyase (PAL), 4-coumarate-CoAligase (4CL), hydroxycinnamoyl CoA:shikimatetransferase (HTC), caffeicacid O-methyltransferase (COMT), and cinnamyl alcohol dehydrogenase (CAD).  Meanwhile, the activities of PAL and LAC increased significantly, finally leading to increased lignin content.  Lignin deposition in the cell wall increased the physical defence ability of transgenic sweetpotato plants, reduced the accumulation of SPVD transmitted by Bemisia tabaci (Gennadius), and promoted healthy sweetpotato growth.  The results provide new insights for disease resistance breeding and green production of sweetpotato. 

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.