BackgroundLow phosphorus availability is a major factor restricting rice growth. Dongxiang wild rice (Oryza rufipogon Griff.) has many useful genes lacking in cultivated rice, including stress resistance to phosphorus deficiency, cold, salt and drought, which is considered to be a precious germplasm resource for rice breeding. However, the molecular mechanism of regulation of phosphorus deficiency tolerance is not clear.ResultsIn this study, cDNA libraries were constructed from the leaf and root tissues of phosphorus stressed and untreated Dongxiang wild rice seedlings, and transcriptome sequencing was performed with the goal of elucidating the molecular mechanisms involved in phosphorus stress response. The results indicated that 1184 transcripts were differentially expressed in the leaves (323 up-regulated and 861 down-regulated) and 986 transcripts were differentially expressed in the roots (756 up-regulated and 230 down-regulated). 43 genes were up-regulated both in leaves and roots, 38 genes were up-regulated in roots but down-regulated in leaves, and only 2 genes were down-regulated in roots but up-regulated in leaves. Among these differentially expressed genes, the detection of many transcription factors and functional genes demonstrated that multiple regulatory pathways were involved in phosphorus deficiency tolerance. Meanwhile, the differentially expressed genes were also annotated with gene ontology terms and key pathways via functional classification and Kyoto Encyclopedia of Gene and Genomes pathway mapping, respectively. A set of the most important candidate genes was then identified by combining the differentially expressed genes found in the present study with previously identified phosphorus deficiency tolerance quantitative trait loci.ConclusionThe present work provides abundant genomic information for functional dissection of the phosphorus deficiency resistance of Dongxiang wild rice, which will be help to understand the biological regulatory mechanisms of phosphorus deficiency tolerance in Dongxiang wild rice.Electronic supplementary materialThe online version of this article (10.1186/s40659-018-0155-x) contains supplementary material, which is available to authorized users.

This work reports a facile synthesis of magnetic hybrids (Fe 3 O 4 -Au hybrids) with high SERS activity for detecting a low abundance of cancer cells. We labeled Raman reporter molecule 4-aminothiophenol (4-ATP) and the antibody of CEA (anti-CEA) on Fe 3 O 4 -Au hybrid nanoparticles (anti-CEA/4-ATP/Fe 3 O 4 -Au) as SERS tags and anti-CEA-labeled Au NPs (anti-CEA/Au) as SERS-active substrates to improve detection sensitivity. In the presence of CEA positive-expressed cancer cells (such as non-small lung cancer cells, A549), sandwich structures were formed as both SERS tags and SERS-active substrates could be bound to CEA at cell surfaces, leading to the formation of SERS hot spots at the junction of SERS tags and SERSactive substrates. As a result, an enhanced SERS signal of 4-ATP arose, which could be used to detect CEA on cell surfaces. This assay can specifically detect CEA-expressed A549 cells at a very low abundance (B10 cells mL À1 ) and can be used for evaluating CEA expression levels of different cancer cells line. This assay has the advantages of high sensitivity (because the SERS technique itself enables the detection of very low concentration analytes, even single molecules), high specificity (because of the enhanced SERS signal arising in sandwich configuration, which is formed in specific antigen-antibody interaction events), and high efficiency (because the magnetic SERS tags can concentrate the captured cells and separate them from the complex detection system without repetitive washing steps). These features make our developed assay a rapid and facile method to sensitively detect a low abundance of cancer cells.

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Red pericarp associates with seed dormancy or preharvest sprouting (PHS) tolerance in crops. To identify this association’s molecular mechanism, a PHS mutant Osviviparous1 (Osvp1) was characterized in rice and crossed with Kasalath, a red pericarp cultivar with Rc (red coleoptiles) genotype. Among the dehulled seeds of F2 progenies, RcRcvp1vp1 seeds performed a lower PHS rate than rcrcvp1vp1 seeds and showed shallower pigmentation than RcRcVP1VP1 seeds. Kasalath and SL9 (an RcRcVP1VP1 substitution line with Nipponbare background) showed more ABA sensitivity than the Nipponbare (rcrcVP1VP1) by the germination assay, and the transcriptional abundance of ABA signal genes OsABI2, OsSnRK2, OsVP1, ABI5, and especially OsVP1 increased in the red pericarp line SL9. Moreover, OsVP1 can directly bind Rc (bHLH) promoter by yeast one-hybrid, which activates Rc and OsLAR expression in red pericarp rice. Furthermore, a luciferase complementation imaging assay showed that OsVP1 interacts with transcriptions factors Rc and OsC1. These results indicate that OsVP1 promotes proanthocyanidin accumulation through the interaction among OsVP1, Rc, and OsC1 and then increases the plant’s ABA sensitivity and PHS resistance.