Occupation of living space is one of the main driving forces of adaptive evolution, especially for aquatic plants whose leaves float on the water surface and thus have limited living space. Euryale ferox, from the angiosperm basal family Nymphaeaceae, develops large, rapidly expanding leaves to compete for space on the water surface. Microscopic observation found that the cell proliferation of leaves is almost completed underwater, while the cell expansion occurs rapidly after they grow above water. To explore the mechanism underlying the specific development of leaves, we performed sequences assembly and analyzed the genome and transcriptome dynamics of E. ferox. Through reconstruction of the three sub-genomes generated from the paleo-hexaploidization event in E. ferox, we revealed that one sub-genome was phylogenetically closer to Victoria cruziana, which also exhibits gigantic floating leaves. Further analysis revealed that while all three sub-genomes promoted the evolution of the specific leaf development in E. ferox, the genes from the sub-genome closer to V. cruziana contributed more to this adaptive evolution. Moreover, we found that genes involved in cell proliferation and expansion, photosynthesis, and energy transportation were overretained and showed strong expression association with the leaf development stages, such as the expression divergence of SWEET orthologs as energy uploaders and unloaders in the sink and source leaf organs of E. ferox. These findings provide novel insights into the genome evolution through polyploidization, as well as the adaptive evolution regarding the leaf development accomplished through biased gene retention and expression sub-functionalization of multi-copy genes in E. ferox.

BackgroundEuryale ferox Salisb., an annual aquatic plant, is the only species in the genus Euryale in the Nymphaeaceae. Seeds of E. ferox are a nutritious food and also used in traditional Chinese medicine (Qian Shi in Mandarin). The molecular events that occurred during seed development in E. ferox have not yet been characterized. In this study, we performed transcriptomic analysis of four developmental stages (T1, T2, T3, and T4) in E. ferox seeds with three biological replicates per developmental stage to understand the physiological and biochemical processes during E. ferox seeds development.Results313,844,425 clean reads were assembled into 160,107 transcripts and 85,006 unigenes with N50 lengths of 2052 bp and 1399 bp, respectively. The unigenes were annotated using five public databases (NR, COG, Swiss-Prot, KEGG, and GO). In the KEGG database, all of the unigenes were assigned to 127 pathways, of which phenylpropanoid biosynthesis was associated with the synthesis of secondary metabolites during E. ferox seed growth and development. Phenylalanine ammonia-lyase (PAL) as the first key enzyme catalyzed the conversion of phenylalanine to trans-cinnamic acid, then was related to the synthesis of flavonoids, lignins and alkaloid. The expression of PAL1 reached its peak at T3 stage, followed by a slight decrease at T4 stage. Cytochrome P450 (P450), encoded by CYP84A1 (which also called ferulate-5-hydroxylase (F5H) in Arabidopsis), was mainly involved in the biosynthesis of lignins.ConclusionsOur study provides a transcriptomic analysis to better understand the morphological changes and the accumulation of medicinal components during E. ferox seed development. The increasing expression of PAL and P450 encoded genes in phenylpropanoid biosynthesis may promote the maturation of E. ferox seed including size, color, hardness and accumulation of medicinal components.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-4707-9) contains supplementary material, which is available to authorized users.

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Objective: To systematically evaluate the clinical efficacy and safety of pertuzumab and trastuzumab combined therapy in human epidermal growth factor receptor 2 (HER-2) positive breast cancer through a meta-analysis. Methods: English databases including PubMed, Embase, and the Cochrane Central Register of Controlled Trials, as well as Chinese databases including China National Knowledge Infrastructure, Wanfang Database, and the Chinese Biomedical Literature Service System (Sinomed), were searched for randomized controlled trials (RCTs) comparing pertuzumab and trastuzumab combined therapy (experimental group) with trastuzumab alone (control group) for the treatment of HER-2 positive breast cancer. The literature search time was from the establishment of the database to July 2022. Two reviewers independently screened the literature, extracted data, and assessed the quality of the literature. Meta-analysis was performed using Review Manager 5.4 software. Results: A total of 9 RCTs involving 7199 patients were included in the meta-analysis. The results of the effectiveness indicators showed that the risk of tumor progression in HER-2 positive breast cancer patients receiving dual-targeted therapy was significantly lower than that in patients receiving trastuzumab alone [Hazard ratios (HR) = 0.68, 95% confidence intervals (CI) (0.58, 0.79), P<0.00001]; the overall survival (OS) of HER-2 positive breast cancer patients receiving dual-targeted therapy was significantly longer than that of patients receiving trastuzumab alone [HR=0.73, 95% CI (0.59, 0.88), P<0.0009]. In terms of safety, there was no statistical difference in the incidence of severe adverse events and ≥3 grade neutropenia between the experimental and control groups (P>0.05), but the incidence of ≥3 grade diarrhea in the experimental group was significantly higher than that in the control group [relative risks = 2.44, 95% CI (1.95, 2.99), P<0.00001]. Conclusion: The combined therapy of pertuzumab and trastuzumab has significant clinical efficacy in HER-2 positive breast cancer patients, and its application can further improve patients' progression-free survival and OS. However, it also increases the risk of adverse reactions to a certain extent. Therefore, in clinical practice, it is necessary to strengthen the monitoring and protection of relevant adverse reactions in patients.