Three species of rape responded to cadmium and melatonin alleviating Cd-toxicity in species-specific strategy.

Cadmium (Cd) pollution has been a significant concern in heavy metal pollution, prompting plants to adopt various strategies to mitigate its damage. While the response of plants to Cd stress and the impact of exogenous melatonin has received considerable attention, there has been limited focus on the responses of closely related species to these factors. Consequently, our investigation aimed to explore the response of three different species of rape to Cd stress and examine the influence of exogenous melatonin in this scenario. The research findings revealed distinctive responses among the investigated rape species. B. campestris showed the resistance to Cd and exhibited lower Cd absorption and sustained its physiological activity under Cd stress. In contrast, B. juncea accumulated much Cd and increased the amount of anthocyanin to mitigate the Cd-damage. Furthermore, B. napus showed the tolerance to Cd and tended to accumulate Cd in vacuoles under Cd stress, thereby decreasing the Cd damage and leading to higher activity of antioxidant enzymes and photosynthesis. Moreover, the application of exogenous melatonin significantly elevated the melatonin level in plants and mitigated Cd toxicity by promoting the activity of antioxidant enzymes, reducing Cd absorption, enhancing the chelating capacity with Cd, decreasing Cd accumulation in organelles, and reducing its fluidity. Specifically, exogenous melatonin increased the FHAc content in B. campestris, elevated the phytochelatins (PCs) level in B. napus, and stimulated photosynthesis in B. juncea. In summary, the findings underscore the species-specific responses of the three species of rape to both Cd stress and exogenous melatonin, highlighting the potential for tailored mitigation strategies based on the unique characteristics of each species.

Physicochemical Characterization of a Fern Polysaccharide from Alsophila spinulosa Leaf and Its Anti-Aging Activity in Caenorhabditis elegans.

Alsophila spinulosa, as a rare tree fern with potential medicinal value, has attracted extensive attention. Herein, the physicochemical properties, antioxidant and anti-aging activities of polysaccharide from A. spinulosa leaf (ALP) were investigated. ALP was composed of galactose, arabinose, glucose, rhamnose, galacturonic acid, mannose, and fucose. (1→), (1→6), and (1→2) bond types were the primary glycosidic bond in ALP. Surprisingly, ALP displayed the wonderful activity of antioxidant and anti-aging, including excellent scavenging ability against DPPH and ABTS radicals in vitro; prolonging the life span, improving activity of antioxidative enzymes (SOD and CAT), and decreasing the level of ROS, MDA in Caenorhabditis elegans. Meanwhile, ALP promoted DAF-16 to move into the nuclear. Overall, our results illustrated that ALP could be further developed as a functional food ingredient.

The jasmonate-responsive transcription factor CbWRKY24 regulates terpenoid biosynthetic genes to promote saponin biosynthesis in Conyza blinii H. Lév.

Conyza blinii H. Lév., the most effective component is saponin, is a biennial medicinal material that needs to be overwintered. WRKY transcription factors family is a large protein superfamily that plays a predominant role in plant secondary metabolism, but their characteristics and functions have not been identified in C. blinii. The CbWRKY24 sequence was selectedfrom the transcriptome database of the C. blinii leaves constructed in our laboratory. Phylogenetic tree analysis revealed that it was associated with AaWRKY1 which can regulate artemisinin synthesis in Artemisia annua. Expression analysis in C. blinii revealed that CbWRKY24 was mainly induced by methyl jasmonate (MeJA) and cold treatments. Transcriptional activity assay showed that it had an independent biological activity. Overexpression of CbWRKY24 in transient transformed C. blinii resulted in improved totalsaponins content, which was attributed to upregulate the expression level of keys genes from mevalonate (MVA) pathway in transient transformed plants compared to wild type (WT) plants. Meanwhile, overexpression the CbWRKY24 in transient transformed tomato fruits showed that the transcript level of related genes in lycopene pathway decreased significantly when compared to WT tomatofruits. Additionally, the MeJA-response-element was found in the promoter regions of CbWRKY24 and the histochemical staining experiments showed that promoter had GUS activity in transiently transformed tobacco leaves. In summary, our results indicated that we may have found a transcription factor that can regulate the biosynthesis of terpenoids in C. blinii.

ß-Amyrin synthase from Conyza blinii expressed in Saccharomyces cerevisiae.

Conyza blinii H.Lév. is a widely used medicinal herb in southwestern China. The main pharmacological components of C. blinii are a class of oleanane-type pentacyclic triterpene glycosides known as conyzasaponins, which are thought to be synthesized from ß-amyrin. However, no genes involved in the conyzasaponin pathway have previously been identified. Here, we identify an oxidosqualene cyclase (OSC), a ß-amyrin synthase, which mediates cyclization of 2,3-oxidosqualene to yield ß-amyrin. Ten OSC sequences were isolated from C. blinii transcript tags. Phylogenetic analysis was used to select the tag Cb18076 as the putative ß-amyrin synthase, named CbßAS. The open reading frame of CbßAS is 2286 bp and encodes 761 amino acids. Its mature protein contains the highly conserved motifs (QXXXGXW/DCTAE) of OSCs and (MWCYCR) of ß-amyrin synthases. Transcription of CbßAS was upregulated 4-24 h after treatment of the seedlings of the C. blinii cultivar with methyl jasmonate. Furthermore, expression of CbßAS in Saccharomyces cerevisiae successfully yielded ß-amyrin. The chemical structures and concentrations of ß-amyrin were confirmed by GC-MS/MS. The target yeast ultimately produced 4.432 mg·L-1 ß-amyrin. Thus, CbßAS is an OSC involved in conyzasaponin biosynthesis.

A Novel Capillary Electrophoresis-Based High-Throughput Multiplex Polymerase Chain Reaction System for the Simultaneous Detection of Nine Pathogens in Swine.

Here we aimed to develop a capillary electrophoresis-based high-throughput multiplex polymerase chain reaction (PCR) system for the simultaneous detection of nine pathogens in swine. Nine pairs of specific primers and a set of universal primers were designed; the multiplex PCR was established. The specificity and cross-reactivity of this assay were examined, and the detection limit was determined using serial 10-fold dilutions of plasmids containing the target sequences. The assay was further tested using 144 clinical samples. We found that the nine specific amplification peaks were observed, and the assay had a high degree of specificity, without nonspecific amplification. The simultaneous detection limit for the nine viruses reached 10000 copies µL-1 when all of the premixed viral targets were present. Seventy-seven of the clinical samples tested positive for at least one of the viruses; the principal viral infections in the clinical samples were porcine circovirus type 2 and porcine reproductive and respiratory syndrome virus. This approach has much potential for further development of high-throughput detection tools for the diagnosis of diseases in animals.