Integrated Cytological, Physiological, and Transcriptome Analyses Provide Insight into the Albino Phenotype of Chinese Plum (Prunus salicina).

Albino seedlings that arise during seed reproduction can have a significant impact on plant growth and breeding. In this research, we present the first report of albino occurrences in the seed reproduction process of Prunus salicina and describe the cytological, physiological, and transcriptomic changes observed in albino seedlings. The albino seedlings which were observed in several plum cultivars exhibited abnormal chloroplast ultrastructure and perturbed stomatal structure. Compared to normal seedlings, the photosynthetic pigment contents in albino seedlings decreased by more than 90%, accompanied by significant reductions in several chlorophyll fluorescence parameters. Furthermore, substantially changed photosynthetic parameters indicated that the photosynthetic capacity and stomatal function were impaired in albino seedlings. Additionally, the activities of the antioxidant enzyme were drastically altered against the background of higher proline and lower ascorbic acid in leaves of albino seedlings. A total of 4048 differentially expressed genes (DEGs) were identified through transcriptomic sequencing, and the downregulated DEGs in albino seedlings were greatly enriched in the pathways for photosynthetic antenna proteins and flavonoid biosynthesis. GLK1 and Ftsz were identified as candidate genes responsible for the impaired chloroplast development and division in albino seedlings. Additionally, the substantial decline in the expression levels of examined photosystem-related chloroplast genes was validated in albino seedlings. Our findings shed light on the intricate physiological and molecular mechanisms driving albino plum seedling manifestation, which will contribute to improving the reproductive and breeding efforts of plums.

Root microbiota confers rice resistance to aluminium toxicity and phosphorus deficiency in acidic soils.

Aluminium (Al) toxicity impedes crop growth in acidic soils and is considered the second largest abiotic stress after drought for crops worldwide. Despite remarkable progress in understanding Al resistance in plants, it is still unknown whether and how the soil microbiota confers Al resistance to crops. Here we found that a synthetic community composed of highly Al-resistant bacterial strains isolated from the rice rhizosphere increased rice yield by 26.36% in acidic fields. The synthetic community harvested rhizodeposited carbon for successful proliferation and mitigated soil acidification and Al toxicity through extracellular protonation. The functional coordination between plants and microbes offers a promising way to increase the usage of legacy phosphorus in topsoil. These findings highlight the potential of microbial tools for advancing sustainable agriculture in acidic soils.

How different are the arsenic fractions inhibit alkaline phosphatases on aggregates scale?

Arsenate [As(V)], in general, is associated with various aggregates and exists as different species in soil, which in turn influences its toxicity and potential contamination. Previous studies have demonstrated the usefulness of alkaline phosphatases (ALP) to evaluate As(V) pollution. However, the effect of different arsenic fractions on ALP among soil aggregates is still unclear. Thus, the distribution of As fractions and ALP kinetics was determined in four-month As-aged paddy soil aggregates. Results revealed the two major fractions of As in aggregates were humic-bound and Fe and Mn oxides-bound [both around 30% under 800 mg kg-1 of As(V)]. Besides, it was observed that available soil phosphorus could positively affect the relative content of water-soluble, exchangeable and carbonate-bound arsenic. In the kinetics experiment, both the Michaelis-Menten constant (Km) and maximum reaction velocity (Vmax) of ALP increased with increasing As(V) concentration under four months ageing for each size aggregate. Multiple linear stepwise regression analysis between kcat and the relative content of arsenic fraction indicated that carbonate-bound arsenic is the main fraction that inhibited the kcat for macroaggregates (> 0.25 mm size). For soil aggregates of 0.1-0.25 mm size, kcat increased with an increase in arsenic residual fraction. As for aggregates <0.1 mm size, Fe and Mn oxide-bound fraction is the main fraction that inhibited the kcat. Overall, this study suggests carbonate-bound and Fe and Mn oxide-bound arsenic fractions could decrease the ALP activities via a decrease in the catalytic efficiency in macroaggregates and <0.1 mm size aggregates, respectively. Besides, available phosphorus should be considered as the main factor when assessing As biotoxicity and mobility.

Chromosome-level draft genome of a diploid plum (Prunus salicina).

BACKGROUND: Plums are one of the most economically important Rosaceae fruit crops and comprise dozens of species distributed across the world. Until now, only limited genomic information has been available for the genetic studies and breeding programs of plums. Prunus salicina, an important diploid plum species, plays a predominant role in modern commercial plum production. Here we selected P. salicina for whole-genome sequencing and present a chromosome-level genome assembly through the combination of Pacific Biosciences sequencing, Illumina sequencing, and Hi-C technology. FINDINGS: The assembly had a total size of 284.2 Mb, with contig N50 of 1.78 Mb and scaffold N50 of 32.32 Mb. A total of 96.56% of the assembled sequences were anchored onto 8 pseudochromosomes, and 24,448 protein-coding genes were identified. Phylogenetic analysis showed that P. salicina had a close relationship with Prunus mume and Prunus armeniaca, with P. salicina diverging from their common ancestor ∼9.05 million years ago. During P. salicina evolution 146 gene families were expanded, and some cell wall-related GO terms were significantly enriched. It was noteworthy that members of the DUF579 family, a new class involved in xylan biosynthesis, were significantly expanded in P. salicina, which provided new insight into the xylan metabolism in plums. CONCLUSIONS: We constructed the first high-quality chromosome-level plum genome using Pacific Biosciences, Illumina, and Hi-C technologies. This work provides a valuable resource for facilitating plum breeding programs and studying the genetic diversity mechanisms of plums and Prunus species.

Combination of flunarizine and transcutaneous supraorbital neurostimulation improves migraine prophylaxis.

OBJECTIVE: This study is aimed to access the efficacy and safety of combination therapy of flunarizine plus transcutaneous supraorbital neurostimulation (tSNS) compared with either flunarizine or tSNS alone for migraine prophylaxis. METHODS: Patients with episodic migraine were enrolled and randomized into 3 groups. Flunarizine 5 mg per day, or tSNS for 20 minutes daily or combination of both were prescribed consecutively for 3 months. The primary outcome measures were changes in migraine days and 50% responder rate of monthly migraine days. Secondary outcome measures were the changes in migraine intensity and intake of rescue medication. Finally, satisfaction to treatment and adverse effect were evaluated as well. RESULTS: A total of 154 were randomized and included in the analysis. After 3 months, the monthly migraine days were decreased in 3 groups and more significant in the combination group. The 50% responder rate was significantly higher (78.43%) in the combination therapy than monotherapy of flunarizine (46.15%) or tSNS (39.22%) alone. Greater reduction of migraine intensity and intake of rescue medication was observed in combination group. There was no difference of adverse events between flunarizine group and combination group (P = .89). CONCLUSION: Adding tSNS to flunarizine can improve the therapeutic efficacy of migraine prophylaxis without increasing the adverse effects. In addition, tSNS is effective and safe for migraine treatment and can be a valid option for migraineurs who are reluctant to take oral medications or for patients who experience a low-migraine frequency and/or intensity that prophylactic therapy is not indicated but desire to acquire medical intervention.

Influence of iron plaque on the uptake and accumulation of chromium by rice (Oryza sativa L.) seedlings: Insights from hydroponic and soil cultivation.

The effects of iron plaque formation on chromium (Cr) uptake and accumulation by rice seedlings (Oryza sativa L.) were assessed using hydroponic and soil experiments, where each 3 levels of Fe supplementation were added to Hoagland solution (0, 30, and 100 mg Fe2+ L-1) and a typical paddy soil (0, 1, and 2 g Fe2+ kg-1). For each treatment, rice seedlings were exposed to different levels of Cr as chromate at 0, 0.5, 2, 5, 10, and 20 mg L-1 in solution or 300 mg kg-1 in soil. Low levels of Cr supply (0.5, 2, and 5 mg L-1) promoted root biomass, while high levels (10 and 20 mg L-1) decreased root and shoot biomass and undermined the density and integrity of iron plaque. Iron supply significantly increased the proportion of Cr in iron plaque, but decreased that in rice plants. The results of hydroponic experiment showed that iron plaque formed with Fe supply at 100 mg L-1 markedly reduced Cr accumulation in shoots of rice seedlings when exposure to 10 and 20 mg L-1 Cr. The soil culture experiment also demonstrated that exogenous Fe addition significantly decreased Cr concentration in leaf and stem of rice seedlings. These results suggested that iron plaque with appropriate amount was effective to reduce the uptake and accumulation of Cr in rice plants, which have strong implication for taking measures to regulate Cr accumulation in rice grains.

Discovery of a non-stereoselective cytochrome P450 catalyzing either 8α- or 8ß-hydroxylation of germacrene A acid from the Chinese medicinal plant, Inula hupehensis.

Sesquiterpene lactones (STLs) are C15 terpenoid natural products with α-methylene γ-lactone moiety. A large proportion of STLs in Asteraceae species is derived from the central precursor germacrene A acid (GAA). Formation of the lactone rings depends on the regio-(C6 or C8) and stereoselective (α- or ß-)hydroxylations of GAA, producing STLs with four distinct stereo-configurations (12,6α-, 12,6ß-, 12,8α-, and 12,8ß-olide derivatives of GAA) in nature. Curiously, two configurations of STLs (C12,8α and C12,8ß) are simultaneously present in the Chinese medicinal plant, Inula hupehensis. However, how these related yet distinct STL stereo-isomers are co-synthesized in I. hupehensis remains unknown. Here, we describe the functional identification of the I. hupehensis cytochrome P450 (CYP71BL6) that can catalyze the hydroxylation of GAA in either 8α- or 8ß-configuration, resulting in the synthesis of both 8α- and 8ß-hydroxyl GAAs. Of these two products, only 8α-hydroxyl GAA spontaneously lactonizes to the C12,8α-STL while the 8ß-hydroxyl GAA remains stable without lactonization. Chemical structures of the C12,8α-STL, named inunolide, and 8ß-hydroxyl GAA were fully elucidated by nuclear magnetic resonance analysis and mass spectrometry. The CYP71BL6 displays 63-66% amino acid identity to the previously reported CYP71BL1/2 catalyzing GAA 6α- or 8ß-hydroxylation, indicating CYP71BL6 shares the same evolutionary lineage with other stereoselective cytochrome P450s, but catalyzes hydroxylation in a non-stereoselective manner. We observed that the CYP71BL6 transcript abundance correlates closely to the accumulation of C12,8-STLs in I. hupehensis. The identification of CYP71BL6 provides an insight into the biosynthesis of STLs in Asteraceae.

Effects of hydroxy safflower yellow-A on tumor capillary angiogenesis in transplanted human gastric adenocarcinoma BGC-823 tumors in nude mice.

OBJECTIVE: To study the effects of hydroxy safflower yellow A (HSYA) on tumor capillary angiogenesis in transplanted human gastric adenocarcinoma BGC-823 tumors in nude mice. METHODS: BGC-823 cells were injected subcutaneously into the right anterior armpit of nude mice to establish an animal model of transplanted tumors. After 24 h, 18 nude mice injected with tumor cells were randomized into model, control, and HSYA 0.028 g/L groups, with six mice in each group. Transplanted tumors were excised on day 20. Tumor inhibition ratios were calculated for the transplanted tumors. Pathological changes and capillary angiogenesis in the tumors were observed by light microscopy. RESULTS: Tumors in the model group grew more quickly than those in the control and HSYA groups, with inhibition ratios of 48% and 30%, respectively. The microvessel count in the HSYA group was lower than in the model group (P < 0.01), and microvessel density was also lower in the HSYA group (P < 0.05). Pathological changes were more obvious in tumors in the model group compared to the HSYA group. CONCLUSION: HSYA inhibits the growth of transplanted BGC-823 tumors, and its effects on tumor capillary angiogenesis may represent one of the mechanisms responsible for this antineoplastic effect.

Tetrandrine induces apoptosis by activating reactive oxygen species and repressing Akt activity in human hepatocellular carcinoma.

Tetrandrine, a bisbenzylisoquinoline alkaloid component of broadly used traditional Chinese medicine, has antitumor effects against some cancers. In our study, we investigated the effects of tetrandrine on the human hepatocellular carcinoma (HCC) in vitro and in vivo. The results showed that tetrandrine effectively induced apoptosis of liver cancer cell in a dose- and time-dependent manner accompanied by alteration of cell morphology, chromatin fragmentation and caspase activation. Tetrandrine treatment also induced intracellular accumulation of reactive oxygen species (ROS), and ROS scavengers (LNAC and GSH) completely blocked the effects of tetrandrine-induced apoptosis, suggesting that the generation of ROS plays an important role in tetrandrine-induced apoptosis. Although the activities of JNK and ERK were inhibited significantly by tetrandrine treatment, JNK and ERK are not involved in the tetrandrine-induced apoptosis. In contrast, Akt activity was found to be closely related to tetrandrine-induced apoptosis. The data demonstrated that Akt activity inhibitor LY294002 synergistically promoted tetrandrine-induced apoptosis of HCC, whereas ectopic expression of Akt contrastly abrogated partial of the tetrandrine-induced apoptosis. These data suggest that Akt signal is the downstream event of ROS generation in the tetrandrine-induced HCC cell apoptosis. Moreover, the results of xenograft in nude mice were consistent with that of the in vitro studies. Therefore, our data suggest that tetrandrine may be a promising agent for the treatment of HCC as a regulator of ROS/Akt pathway.

[Effects of HSYA on expression of bFGF protein and MMP-9 in BGC-823 transplantation tumor of nude mice].

OBJECTIVE: To investigate the effects of hydroxy safflor yellow A (HSYA) on the expression of bFGF protein and MMP-9 mRNA or protein of transplantation tumor of gastric adenocarcinoma cell line BGC-823 in nude mice. METHOD: The BGC-823 cells were subcutaneously injected into the right anterior armpit of BALB/C nu/nu nude mice, and the animal model of transplantation tumor was established. The experimental groups were treated with HSYA at concentration of 0.056 and 0.028 g x L(-1) and cyclophosphamide at 2 g x L(-1), or with physiologic saline. The tumor inhibitory effect was observed, and the mRNA expression of MMP-9 of transplantation tumor was detected by real time-fluorescent quantitation PCR and the protein expression of MMP-9 and bFGF were detected by enzyme linked immunosorbent assay. RESULT: The IR in the group with HSYA at the concentration of 0.028 g x L(-1) is higher than in the group with normal sodium. After treatment with HSYA, the mRNA expression of MMP-9 has significant difference at the concentration of 0.028 g x L(-1) as compared with physiologic saline-treated group (P < 0.05), but the protein expression of MMP-9 and bFGF is obviously less than that in the physiologic saline-treated group (P < 0.05). CONCLUSION: The possible mechanism of HSYA in given concentration to antagonize tumor angiogenesis may be related with inhibiting the protein expression of MMP-9 and bFGF or the mRNA expression of MMP-9 in tumor tissue to reduce the degradation of blood vessel basilar membrane, and to restrain the migration of blood vessel and decrease the tumor vascularization.

[Effects of hydroxy safflor yellow A on blood vessel and mRNA expression with VEGF and bFGF of transplantation tumor with gastric adenocarcinoma cell line BGC-823 in nude mice].

OBJECTIVE: To investigate the effects of Hydroxy Safflor yellow A (HSYA) on the growth of blood vessel of transplantation tumor of gastric adenocarcinoma cell line BGC-823 in nude mice and its underlying mechanism of antagonizing tumor angiogenesis. METHOD: The BGC-823 cells was subcutaneouly injected into the right anterior armpit of BALB/C nu/nu nude mice and established the animal model of transplantation tumor. Then nude mice were divided into 4 groups at random: model group, control group, high or low dosage of HSYA group. The model group were treated with normal sodium by intraperitoneal injection, HSYA groups were treated with HSYA at concentration of 0.056 g x L(-1) and 0.028 g x L(-1) by intraperitoneal injection, and in these groups each mouse was injected 2 times everyday with 0.2 mL by 4-6 hours interval. The control group were injected in enterocoelia 1 times every 2 days starting from the third day with cytoxan at 2 g x L(-1). 20 days later, the volume and weight of nude mice were observed. The pathological change of tumor tissue was observed under optical microscope. The mRNA expression of VEGF and bFGF of transplantation tumor were detected by real time quantitative PCR. RESULT: The volume (607.42 +/- 252.96) mm3, weight (0.88 +/- 0.14) g of transplantation tumor, the mRNA expression level of VEGF 0.49 +/- 0.13 and bFGF 0.60 +/- 0.48 are reduced significantly after treatment with HSYA at the concentration of 0.028 g x L(-1) compared with physiologic saline-treated group (P < 0.05 or P < 0.01). The tumor pathological angiogenesis of HSYA group is also less obvious than the normal sodium-treated group. CONCLUSION: HSYA in given concentration can inhibit the growth of BGC-823 transplantation tumor, and decreasing the mRNA expression of VEGF and bFGF, which suggests that inhibiting tumor angiogenesis may be one of the mechanisms of HSYA antagonizing tumor.