Transcriptome analysis reveals the molecular mechanisms of response to an emergent yellow-flower disease in green Chinese prickly ash (Zanthoxylum schinifolium)

Chinese prickly ash (Zanthoxylum) is extensively used as spice and traditional medicine in eastern Asian countries. Recently, an emergent yellow-flower disease (YFD) break out in green Chinese prickly ash (Zanthoxylum schinifolium, Qinghuajiao in Chinese) at Chongqing municipality, and then leads to a sharp reduction in the yield of Qinghuajiao, and thus results in great economic losses for farmers. To address the molecular response for the emergent YFD of Qinghuajiao, we analyzed the transcriptome of 12 samples including the leaves and inflorescences of asymptomatic and symptomatic plants from three different towns at Chongqing by high-throughput RNA-Seq technique. A total of 126,550 genes and 229,643 transcripts were obtained, and 21,054 unigenes were expressed in all 12 samples. There were 56 and 164 different expressed genes (DEGs) for the AL_vs_SL (asymptomatic leaf vs symptomatic leaf) and AF_vs_SF (asymptomatic flower vs symptomatic flower) groups, respectively. The results of KEGG analysis showed that the “phenylpropanoid biosynthesis” pathway that related to plant–pathogen interaction were found in AL_vs_SL and AF_vs_SF groups, and the “Plant–pathogen interaction” found in AF_vs_SF group, implying that this Qinghuajiao YFD might cause by plant pathogen. Interestingly, we detected 33 common unigenes for the 2 groups, and almost these unigenes were up-regulated in the symptomatic plants. Moreover, most of which were homologs to virus RNA, the components of viruses, implying that this YFD was related to virus. Our results provided a primary molecular basis for the prevention and treatment of YFD of Qinghuajiao trees.

Resource evaluation and novel germplasm excavation of wild Chinese prickly ash in Qinling mountains

Wild Chinese prickly ash with elevated antioxidants is a valuable genetic resource for Zanthoxylum bungeanum Maxim improvement. There are rich wild germplasm resources in the Qinling Mountains. In a study with wild germplasm resources from different altitudes and six cultivated varieties, the phenolic and flavonoid compounds were analyzed by high performance liquid chromatography (HPLC). The chromatograms of them were basically the same, although their chemical composition content was greatly different. The thirty samples were divided into three categories through the hierarchical clustering analysis. And catechin, hyperoside and quercitrin were considered to be key compound for the quality evaluation, by contrast, the wild samples with an altitude of 2300±50 m (Ⅳ group) had the highest content of key compounds, and showed stronger antioxidant activity and antibacterial ability, indicating that these wild samples could be used as an excellent breeding resource. This is the first time to evaluate the quality of wild Chinese prickly ash in different altitude areas of Qinling Mountains. These excellent wild germplasm resources provided substantial potential accessions for use directly in Chinese prickly ash breeding programs.

Heterologous immunoassay strategy for enhancing detection sensitivity of banned dye rhodamine B in fraudulent food

Background The high quality of antibody (Ab) is critical for an immunoassay; usually, an Ab with low affinity is often regarded as a “bad” one in the immunoassay development. How to use a “bad” Ab to develop a highly sensitive immunoassay is still a huge challenge. Methods In this study, a heterologous immunoassay strategy was designed to enhance the sensitivity for the detection of banned dye, rhodamine B (RB), in fraudulent food. The RB Ab could not recognize RB by pairing with homologous coating antigen (Ag). However, the Ab showed unexpected high specificity and sensitivity recognition after being replaced by heterologous coating Ag. Indirect competitive enzyme-linked immunosorbent assay (icELISA) was developed based on the heterologous strategy. Results The detection limit of icELISA for chilli powder, Chinese prickly ash, hot-pot seasoning, and chilli sauce was 0.002 μg/kg, and the recoveries of the four samples ranged from 76.0 to 102.0%, with the coefficient of variation between 3.9 and 18.8%. Parallel experiment for 20 market samples with high-performance liquid chromatography (HPLC) was performed on to confirm the performance of the practical application of the developed icELISA, and the results of the two methods had good correlation. Molecular modeling inferred that the carboxyl group of hapten and its exposure level played an important role in the hapten-Ab recognition. Conclusions The proposed icELISA can be used for the surveillance screening of RB in a range of seasoning foods, and the heterologous strategy is an effective approach to enhance the sensitivity in an immunoassay.