Genome-wide characterization of MATE family members in Cucumis melo L.and their expression profiles in response to abiotic and biotic stress

The multidrug and toxic compound extrusion(MATE) family plays pivotal roles in the detoxification process in plants, while no information has been provided for this gene family in melon(Cucumis melo L.) thus far, limiting our understanding of its functions in melon acclimation to stressful environments. In this study, a total of 39 MATEs(CmMATE1–CmMATE39) were observed in the melon genome;these were unevenly distributed in all chromosomes, with the most on Chromosome 1. Based on their orthologous relationship with those from Arabidopsis, rice, and sorghum, melon MATEs were clustered into three subfamilies of Clades Ⅰ, Ⅱ, and Ⅲ, wherein 23, 9, and 7 members were included, respectively.Variable exon number was observed in CmMATEs, and the most were harbored by CmMATE8. Gene ontology(GO) term and cis-regulatory element(CRE) analyses pointed to the potential roles of CmMATEs in both the regulation of melon development and acclimation to various abiotic and biotic stressors. The RNA-seq and qRT-PCR(quantitative real-time PCR) results demonstrated that under normal growth conditions, CmMATEs were expressed in a tissue-and development-specific manner, while their abundance apparently varied in a stress-dependent manner when melon plants were exposed to unfavorable environmental conditions. Altogether, these observations could expand our knowledge about the plant MATE family and benefit functional genomics analysis for CmMATEs in the future.

Genome-Wide Identification of Two-Component Signal Transduction System Genes in Melon (<I>Cucumis melon</I>L.)

Two-component system (TCS) is responsible for cytokinin signaling, which plays critical roles in plant development and physiological process. This system is generally composed of two signaling factors, a histidine kinase (HK) and a response regulator (RR) that is associated with a histidine phosphotransfer (HP) protein. In this study, we performed systematic investigation on TCS genes in melon (Cucumis melon L.). We identified 44 TCS genes in melon, including 18 HK(L)s (9 HKs and 9 HKLs), 5 HPs (4 authentic and 1 pseudo), and 21 RRs (7 Type-A, 8 Type-B, and 6 pseudo). The classification and structure of these melon TCS members were introduced in detail as well. Our results provided new insights into the characteristics of the melon TCS genes and might benefit their functional study in future.

Integrative analysis of transcriptomic and metabolomic profiles reveals new insights into the molecular foundation of fruit quality formation in Citrullus lanatus(Thunb.)Matsum.&Nakai

In this study,an integrated transcriptome and metabolome analysis was used to explore the molecular foundation of fruit quality in two parent lines of Citrullus lanatus with distinct flesh characteristics,including ‘14-1’(sweet,red,and soft)andW600'(bitter,light yellow,and firm),as well as the corresponding F,population(bitter,light yellow,and firm).Numerous differentially expressed genes(DEGs)were identified in the fruit samples:3766 DEGs for ‘14-1’vs.W600,2767 for ‘14-1’vs.F_(1),and 1178 for F_(1) vs.‘W600’at the transition stage;and 4221 for ‘14-1’vs.W6002447 for ‘14-1’vs.F,and 446 for F,vs.‘W600’at the maturity stage.Weighted gene co-expression network analysis(WGCNA)revealed that a gene module including 1111 DEGs was closely associated with flesh taste and color,and another gene module including 1575 DEGs contributed significantly to flesh texture.The metabolomic results showed that there were 447 differential metabolites(DMs)for ‘14-1’vs.‘W600’fruits,394 for ‘14-1’vs.F,and 298 for F,vs.‘W600’at the maturity stage.Combining WGNCA and metabolomic results,several DEGs and DMs were further identified as hub players in fruitqualityformation:6DEGs with 4DMs for flesh sweetness;6DEGs with 13DMs forbitterness;9DEGs with 10 DMs for flesh color;and 9 DEGs with 4 DMs for flesh texture.Altogether,these observations not only expand our knowledge of the molecular basis of fruit quality in watermelon,but also provide potential targets for future watermelon improvement.

Prognostic factors for patients with limited-stage small-cell lung cancer without receiving prophylactic cranial irradiation

Objective:This retrospective study aims to explore the risk factors for brain metastasis and the prognostic factors for overall survival(OS)in patients with limited-stage small-cell lung cancer(LS-SCLC)who have no brain metastases according to magnetic resonance imaging(MRI)and have not received prophylactic cranial irradiation(PCI)after first-line chemoradiotherapy.Methods:A total of 107 patients who were treated in the Fourth Hospital of Hebei Medical University from January 2013 to December 2017 were enrolled in this study.The patients were treated with etoposide/platinum chemotherapy and thoracic radiotherapy(TRT)with involved-field irradiation.The median dose of the radiotherapy was 60 Gy(50-64 Gy).The primary study endpoints include BMFS(brain-metastasis-free survival)and OS(overall survival).The Kaplan-Meier method was applied to estimate survival,with a log-rank test used to ascertain statistical significance.The multivariate Cox proportional hazards model was used to determine the prognostic factors for survival.Results:The median follow-up of all patients was 18.8 months(range:7.9–65.1 months)and the median follow-up of surviving patients was 26.7 months(range:18.8–65.1 months).The median OS of the whole cohort was 20.1 months,and the 1-,2-and 3-year OS rates were 84.9%,44.9%,and 25.9%,respectively.The 1-,2-,and 3-year BMFS rates were 69.0%,49.9%,and 40.7%,respectively.50 patients(46.7%)developed brain metastases during the follow-up period,and the median time from the start to brain metastasis was 10.7 months(range:4.8–31.1 months).As shown by multivariate analysis,independent prognostic factors of OS included cycles of chemotherapy(P=0.019),the response to initial treatment(P=0.011),and the start time of TRT(P=0.044).The independent prognostic factors of BMFS included the clinical stage(P=0.008),the response to initial treatment(P=0.024),and the start time of TRT(P=0.028).Conclusions:For patients with LS-SCLC who have not received PCI,favorable factors for lower brain metastasis and higher survival include early clinical stage,CR to initial chemoradiotherapy,early TRT,and adequate cycles of chemotherapy.PCI is still recommended as the standard modality since the incidence of brain metastases was high(46.7%).