The effect of β-cyclocitral treatment on the carotenoid content of transgenic Marsh grapefruit (Citrus paradisi Macf.) suspension-cultured cells

Zheng, Xiongjie, Zhu, Kaijie, Ye, Junli, Price, Elliott J., Deng, Xiuxin, Fraser, Paul D. (2020): The effect of β-cyclocitral treatment on the carotenoid content of transgenic Marsh grapefruit (Citrus paradisi Macf.) suspension-cultured cells. Phytochemistry (112509) 180: 1-8, DOI: 10.1016/j.phytochem.2020.112509, URL: http://dx.doi.org/10.1016/j.phytochem.2020.11250

Comparative transcripts profiling reveals new insight into molecular processes regulating lycopene accumulation in a sweet orange (Citrus sinensis) red-flesh mutant

<p>Abstract</p> <p>Background</p> <p>Interest in lycopene metabolism and regulation is growing rapidly because accumulative studies have suggested an important role for lycopene in human health promotion. However, little is known about the molecular processes regulating lycopene accumulation in fruits other than tomato so far.</p> <p>Results</p> <p>On a spontaneous sweet orange bud mutant with abnormal lycopene accumulation in fruits and its wild type, comparative transcripts profiling was performed using Massively Parallel Signature Sequencing (MPSS). A total of 6,877,027 and 6,275,309 reliable signatures were obtained for the wild type (WT) and the mutant (MT), respectively. Interpretation of the MPSS signatures revealed that the total number of transcribed gene in MT is 18,106, larger than that in WT 17,670, suggesting that newly initiated transcription occurs in the MT. Further comparison of the transcripts abundance between MT and WT revealed that 3,738 genes show more than two fold expression difference, and 582 genes are up- or down-regulated at 0.05% significance level by more than three fold difference. Functional assignments of the differentially expressed genes indicated that 26 reliable metabolic pathways are altered in the mutant; the most noticeable ones are carotenoid biosynthesis, photosynthesis, and citrate cycle. These data suggest that enhanced photosynthesis and partial impairment of lycopene downstream flux are critical for the formation of lycopene accumulation trait in the mutant.</p> <p>Conclusion</p> <p>This study provided a global picture of the gene expression changes in a sweet orange red-flesh mutant as compared to the wild type. Interpretation of the differentially expressed genes revealed new insight into the molecular processes regulating lycopene accumulation in the sweet orange red-flesh mutant.</p

Genetically modified adenoviral vector with the protein transduction domain of Tat improves gene transfer to CAR-deficient cells

The transduction efficiency of Ad (adenovirus) depends, to some extent, on the expression level of CAR (coxsackievirus and Ad receptor) of a target cell. The low level of CAR on the cell surface is a potential barrier to efficient gene transfer. To overcome this problem, PTD.AdeGFP (where eGFP is enhanced green fluorescent protein) was constructed by modifying the HI loop of Ad5 (Ad type 5) fibre with the Tat (trans-activating) PTD (protein transduction domain) derived from HIV. The present study showed that PTD.AdeGFP significantly improved gene transfer to multiple cell types deficient in expression of CAR. The improvement in gene transfer was not the result of charge-directed binding between the virus and the cell surface. Although PTD.AdeGFP formed aggregates, it infected target cells in a manner different from AdeGFP aggregates precipitated by calcium phosphate. In addition, PTD.AdeGFP was able to transduce target cells in a dynamin-independent pathway. The results provide some new clues as to how PTD.AdeGFP infects target cells. This new vector would be valuable in gene-function analysis and for gene therapy in cancer

Room temperature Si:S barrier infrared detector with broadband response up to 4.4{\mu}m

Mid-infrared spectrum is a critical tool for chemical analysis, industrial inspection, environment, and other fields due to its rich chemical bond information. However, the complicated growth or fabrication procedures of existing mid-infrared sensitive materials hinder the large-scale production and utilization of mid-infrared detectors. To address this issue, we developed Si:S barrier detectors employing sulfur doped silicon and a sophisticated band barrier design. Since the transport of dark current and photo current is separated, the barrier design effectively suppresses the dark current while allowing the photo current to leverage gain mechanisms, thereby substantially improving signal-to-noise ratio. As a result, the detector exhibits an infrared response range covering from 1.12 to 4.4{\mu}m with a peak at 3.3{\mu}m, excluding its intrinsic response in visible range. Its peak quantum efficiency surpasses that of the best mid-infrared silicon-based detector reported to date by an order of magnitude, reaching 2% at room temperature. The peak detectivity at 90K is 1.4E11 Jones @1.4V and decreases to 4.4E9 Jones @1.4V, 210K, comparable to the typical III-V and IV-VI photodetectors at one thousandth fabrication cost. Leveraging the well-established silicon-based manufacturing process, this device holds promise for large-scale production at a reduced price, offering a cost-effective solution for future mid-infrared detection

Combining high-throughput micro-CT-RGB phenotyping and genome-wide association study to dissect the genetic architecture of tiller growth in rice

Manual phenotyping of rice tillers is time consuming and labor intensive and lags behind the rapid development of rice functional genomics. Thus, automated, non-destructive phenotyping of rice tiller traits at a high spatial resolution and high-throughput for large-scale assessment of rice accessions is urgently needed. In this study, we developed a high-throughput micro-CT-RGB (HCR) imaging system to non-destructively extract 730 traits from 234 rice accessions at 9 time points. We could explain 30% of the grain yield variance from 2 tiller traits assessed in the early growth stages. A total of 402 significantly associated loci were identified by GWAS, and dynamic and static genetic components were found across the nine time points. A major locus associated with tiller angle was detected at nine time points, which contained a major gene TAC1. Significant variants associated with tiller angle were enriched in the 3'-UTR of TAC1. Three haplotypes for the gene were found and rice accessions containing haplotype H3 displayed much smaller tiller angles. Further, we found two loci contained associations with both vigor-related HCR traits and yield. The superior alleles would be beneficial for breeding of high yield and dense planting

Inhibiting MARSs reduces hyperhomocysteinemia‐associated neural tube and congenital heart defects

Hyperhomocysteinemia is a common metabolic disorder that imposes major adverse health consequences. Reducing homocysteine levels, however, is not always effective against hyperhomocysteinemia‐associated pathologies. Herein, we report the potential roles of methionyl‐tRNA synthetase (MARS)‐generated homocysteine signals in neural tube defects (NTDs) and congenital heart defects (CHDs). Increased copy numbers of MARS and/or MARS2 were detected in NTD and CHD patients. MARSs sense homocysteine and transmit its signal by inducing protein lysine (N)‐homocysteinylation. Here, we identified hundreds of novel N‐homocysteinylated proteins. N‐homocysteinylation of superoxide dismutases (SOD1/2) provided new mechanistic insights for homocysteine‐induced oxidative stress, apoptosis and Wnt signalling deregulation. Elevated MARS expression in developing and proliferating cells sensitizes them to the effects of homocysteine. Targeting MARSs using the homocysteine analogue acetyl homocysteine thioether (AHT) reversed MARS efficacy. AHT lowered NTD and CHD onsets in retinoic acid‐induced and hyperhomocysteinemia‐induced animal models without affecting homocysteine levels. We provide genetic and biochemical evidence to show that MARSs are previously overlooked genetic determinants and key pathological factors of hyperhomocysteinemia, and suggest that MARS inhibition represents an important medicinal approach for controlling hyperhomocysteinemia‐associated diseases

Transposable elements cause the loss of self-incompatibility in citrus

Self-incompatibility (SI) is a widespread prezygotic mechanism for flowering plants to avoid inbreeding depression and promote genetic diversity. Citrus has an S-RNase-based SI system, which was frequently lost during evolution. We previously identified a single nucleotide mutation in Sm-RNase, which is responsible for the loss of SI in mandarin and its hybrids. However, little is known about other mechanisms responsible for conversion of SI to self-compatibility (SC) and we identify a completely different mechanism widely utilized by citrus. Here, we found a 786-bp miniature inverted-repeat transposable element (MITE) insertion in the promoter region of the FhiS2-RNase in Fortunella hindsii Swingle (a model plant for citrus gene function), which does not contain the Sm-RNase allele but are still SC. We demonstrate that this MITE plays a pivotal role in the loss of SI in citrus, providing evidence that this MITE insertion prevents expression of the S-RNase; moreover, transgenic experiments show that deletion of this 786-bp MITE insertion recovers the expression of FhiS2-RNase and restores SI. This study identifies the first evidence for a role for MITEs at the S-locus affecting the SI phenotype. A family-wide survey of the S-locus revealed that MITE insertions occur frequently adjacent to S-RNase alleles in different citrus genera, but only certain MITEs appear to be responsible for the loss of SI. Our study provides evidence that insertion of MITEs into a promoter region can alter a breeding strategy and suggests that this phenomenon may be broadly responsible for SC in species with the S-RNase system