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Chlamydomonas reinhardtii is a well-established microalgal model species with a shorter doubling time, which is a promising natural source for the efficient production of high-value carotenoids. In the microalgal carotenoid biosynthetic pathway, lycopene is converted either into β-carotene by lycopene β-cyclase or into α-carotene by lycopene ε-cyclase (LCYE) and lycopene β-cyclase. In this study, we overexpressed the LCYE gene in C. reinhardtii to estimate its effect on lycopene metabolism and lutein production. Chlamydomonas transformants (CrLCYE#L1, #L5, and #L6) produced significantly increased amounts of lutein per culture (up to 2.6-fold) without a decrease in cell yields. Likewise, the expression levels of LCYE gene in transformants showed a significant increase compared with that of the wild-type strain. These results suggest that LCYE overexpression enhances the conversion of lycopene to α-carotene, which in turn improves lutein productivity. Interestingly, their β-carotene productivity appeared to increase slightly rather than decrease. Considering that the inhibition of the lycopene cyclization steps often induces higher expression in genes upstream of metabolic branches, this result implies that the redirection from β-carotene to α-carotene by LCYE overexpression might also enhance upstream gene expression, thereby leading to auxiliary β-carotene production.

Our previous studies found overexpression of Musashi2 (MSI2) conduced to the progression and chemoresistance of pancreatic cancer (PC) by negative regulation of Numb and wild type p53 (wtp53). Now, we further investigated the novel signalling involved with MSI2 in PC. We identified inositol-3-phosphate synthase 1 (ISYNA1) as a novel tumour suppressor regulated by MSI2. High MSI2 and low ISYNA1 expression were prevalently observed in 91 PC tissues. ISYNA1 expression was negatively correlated with MSI2 expression, T stage, vascular permeation and poor prognosis in PC patients. What's more, patients expressed high MSI2 and low ISYNA1 level had a significant worse prognosis. And in wtp53 Capan-2 and SW1990 cells, ISYNA1 was downregulated by p53 silencing. ISYNA1 silencing promoted cell proliferation and cell cycle by inhibiting p21 and enhanced cell migration and invasion by upregulating ZEB-1. However, MSI2 silencing upregulated ISYNA1 and p21 but downregulated ZEB-1, which can be rescued by ISYNA1 silencing. Moreover, reduction of cell migration and invasion resulting from MSI2 silencing was significantly reversed by ISYNA1 silencing. In summary, MSI2 facilitates the development of PC through a novel ISYNA1-p21/ZEB-1 pathway, which provides new gene target therapy for PC., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Chalcone isomerase (CHI) is a key component of phenylalanine metabolism that can produce a variety of flavonoids. However, little information and no systematic analysis of CHI genes is available for cotton. Here, we identified 33 CHI genes in the complete genome sequences of four cotton species ( Gossypium arboretum L., Gossypium raimondii L., Gossypium hirsutum L., and Gossypium barbadense L.). Cotton CHI proteins were classified into two main groups, and whole-genome/segmental and dispersed duplication events were important in CHI gene family expansion. qRT-PCR and semiquantitative RT-PCR results suggest that CHI genes exhibit temporal and spatial variation and respond to infection with Fusarium wilt race 7. A preliminary model of CHI gene involvement in cotton evolution was established. Pairwise comparison revealed that seven CHI genes showed higher expression in cultivar 06-146 than in cultivar Xinhai 14. Overall, this whole-genome identification unlocks a new approach to the comprehensive functional analysis of the CHI gene family, which may be involved in adaptation to plant pathogen stress., Competing Interests: The authors declare no conflict of interest.

Triterpene cyclases catalyze the first committed step in triterpene biosynthesis, by forming mono- to pentacyclic backbone structures from oxygenated C30 isoprenoid precursors. Squalene epoxidase precedes this cyclization by providing the oxygenated and activated substrate for triterpene biosynthesis. Three squalene epoxidases from Cucurbita pepo (CpSEs) were isolated and shown to have evolved under purifying selection with signs of sites under positive selection in their N- and C-termini. They all localize to the Endoplasmic Reticulum (ER) and produce 2,3-oxidosqualene and 2,3:22,23-dioxidosqualene when expressed in a yeast erg1 (squalene epoxidase) erg7 (lanosterol synthase) double mutant. Co-expression of the CpSEs with four different triterpene cyclases, either transiently in Nicotiana benthamiana or constitutively in yeast, showed that CpSEs boost triterpene production. CpSE2 was the best performing in this regard, which could reflect either increased substrate production or superior channeling of the substrate to the triterpene cyclases. Fluorescence Lifetime Imaging Microscopy (FLIM) analysis with C. pepo cucurbitadienol synthase (CpCPQ) revealed a specific interaction with CpSE2 but not with the other CpSEs. When CpSE2 was transformed into C. pepo hairy root lines, cucurbitacin E production was increased two folds compared to empty vector control lines. This study provides new insight into the importance of SEs in triterpene biosynthesis, suggesting that they may facilitate substrate channeling, and demonstrates that SE overexpression is a new tool for increasing triterpene production in plants and yeast., (Copyright © 2018. Published by Elsevier Inc.)

Previously we described flax plants with expression of Arabidopsis lycopene β-cyclase (lcb) gene in which decreased expression of the endogenous lcb and increased resistance to fungal pathogen was observed. We suggested that co-suppression was responsible for the change. In this study we investigated the molecular basis of the observed effect in detail. We found that methylation changes in the Lulcb gene body might be responsible for repression of the gene. Treatment with azacitidine (DNA methylation inhibitor) confirmed the results. Moreover, we studied how the manipulation of carotenoid biosynthesis pathway increased ABA level in these plants. We suggest that elevated ABA levels may be responsible for the increased resistance of the flax plants to pathogen infection through activation of chitinase (PR gene)., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Tomato (Solanum lycopersicum L.) is one of the model plant to study carotenoid biosynthesis. In the present study, the fruit carotenoid content were quantified at different developmental stages for two contrasting genotypes, viz. IIHR-249-1 and IIHR-2866 by UPLC. Lycopene content was high in IIHR-249-1 (19.45 mg/100 g fresh weight) compared to IIHR-2866 (1.88 mg/100 g fresh weight) at the ripe stage. qPCR was performed for genes that are involved in the carotenoid biosynthetic pathway to study the difference in lycopene content in fruits of both the genotypes. The expression of Phytoene synthase (PSY) increased by 36-fold and Phytoene desaturase (PDS) increased by 14-fold from immature green stage to ripe stage in IIHR-249-1. The expression of Chloroplast lycopene beta-cyclase (LCY-B) and Chromoplast lycopene beta cyclase (CYC-B) decreased gradually from the initial stage to the ripe stage in IIHR-249-1. IIHR 249-1 showed 3- and 1.8-fold decrease in gene expression for Chloroplast lycopene beta-cyclase (LCY-B) and Chromoplast lycopene beta-cyclase (CYC-B) .The F2 hybrids derived from IIHR-249-1 and IIHR-2866 were analysed at the ripe stage for lycopene content. The gene expression of Chloroplast lycopene beta-cyclase (LCY-B) and Chromoplast lycopene beta-cyclase (CYC-B) in high and low lycopene lines from F2 progenies also showed the decrease in transcript levels of both the genes in high lycopene F2 lines. We wish to suggest that the differential expression of lycopene beta-cyclases can be used in marker-assisted breeding.

Main Conclusion: Arabidopsis promoters of genes BANYULS and FRUITFULL are transcribed in Camelina. They triggered the transcription of limonene synthase and induced higher limonene production in seeds and fruits than CaMV 35S promoter. Camelina sativa (Camelina) is an oilseed crop of relevance for the production of biofuels and the plant has been target of a recent and intense program of genetic manipulation aimed to increase performance, seed yield and to modify the fatty acid composition of the oil. Here, we have explored the performance of two Arabidopsis thaliana (Arabidopsis) promoters in triggering transgene expression in Camelina. The promoters of two genes BANYULS (AtBAN pro ) and FRUITFULL (AtFUL pro ), which are expressed in seed coat and valves of Arabidopsis, respectively, have been chosen to induce the expression of limonene synthase (LS) from Citrus limon. In addition, the constitutive CaMV 35S promoter was utilized to overexpress LS in Camelina . The results of experiments revealed that AtBAN pro and AtFUL pro are actively transcribed in Camelina where they also retain specificity of expression in seeds and valves as previously observed in Arabidopsis. LS induced by AtBAN pro and AtFUL pro leads to higher limonene production in seeds and fruits than when the CaMV 35S was used to trigger the expression. In conclusion, the results of experiments indicate that AtBAN pro and AtFUL pro can be successfully utilized to induce the expression of the transgenes of interest in seeds and fruits of Camelina.