Fruit traits affect population genetic diversity by affecting seed protection and dispersal strategies, thereby comprising important components of phenotypic variation. Understanding of the phenotypic variation is an indispensable first step for developing breeding strategies. However, little information is known about the genetic variation in E . japonica —a monotypic species with abundant phenotypes that is mainly distributed in southern China. In this study, we evaluated the phenotypic diversity of 67 E . japonica using 23 phenotypic traits. Our results showed that the Shannon–Wiener ( I ) index of qualitative traits ranged from 0.55 to 1.26, and the color traits had a relatively high I . The average coefficient of variation of compound leaf traits (14.74%) was higher than that of fruit and seed traits (12.77% and 11.47%, respectively). Principal component analysis also showed that compound leaf and fruit traits were important components of total variation. Furthermore, correlation analysis revealed a significant difference in elevation and fruit color, irregular ribs, leaf margin and texture. The F value within populations was smaller than among populations, indicating the variation in phenotypic traits among populations was much greater than within populations. Dehua and Zunyi populations had the highest coefficients of variation, whereas Wenzhou population had the smallest—which may be attributed to habitat destruction. According to Q-type clustering, 67 samples clustered into four groups, with those having similar phenotypes clustering into the same group. In general, leaf and fruit traits had abundant phenotypic diversity, representing the main sources of phenotypic variation. Combined with clustering results and field surveys, this study suggests that the phenotypes of E . japonica are classified into two main categories: The deciduous E . japonica present at high altitudes; and the evergreen E . japonica present at low altitudes. Excavating E . japonica variations provides a theoretical reference for its classification and diversity, and is of great significance for planning genetic resources and establishing conservation strategies.

Flower and fruit colors are of vital importance to the ecology and economic market value of plants. The mechanisms of flower and fruit coloration have been well studied, especially among ornamental flower plants and cultivated fruits. As people pay more attention to exocarp coloration, the endocarp coloration in some species has often been ignored. Here, we report on the molecular mechanism of endocarp coloration in three development stages of Euscaphis konishii. The results show that endocarp reddening is closely related to anthocyanin accumulation, and a total of 86,120 unigenes were assembled, with a mean length of 893 bp (N50 length of 1642 bp). We identified a large number of differentially expressed genes associated with endocarp coloration, including anthocyanin biosynthesis, carotenoid biosynthesis, and chlorophyll breakdown. The genes participating in each step of the anthocyanin biosynthesis were found in the transcriptome dataset, but a few genes were found in the carotenoid biosynthesis and chlorophyll breakdown. In addition, the candidate R2R3-MYB transcription factors and candidate glutathione S-transferase transport genes, which likely regulate the anthocyanin biosynthesis, were identified. This study offers a platform for E. konishii functional genomic research and provides a reference for revealing the regulatory mechanisms of endocarp reddening.

We have described and illustrated a new species, Bulbophyllum yunxiaoense (Malaxideae, Epidendroideae, Orchidaceae), from Fujian Province in southeast China. The size and overall floral morphology of the new species are similar to those of Bulbophyllum pingtungense, a species endemic to Taiwan Island on the southeast coast of China and its closest relative according to a cladistic analysis of nuclear (ITS) and plastid (matK, trnL-F, and atpI-atpH) DNA sequences. However, B. yunxiaoense is distinguishable from B. pingtungense by flower colour, shorter scape, and longer lateral sepal.

Background. Quantitativereal-time reverse transcriptase polymerase chain reaction is the common method to quantify relative gene expression. Normalizating using reliable genes is critical in correctly interpreting expression data from qRT-PCR. Euscaphis konishii is a medicinal plant with a long history in China, which has various chemical compounds in fruit. However, there is no report describing the selection of reference genes in fruit development of Euscaphis konishii. Methods. We selected eight candidate reference genes based on RNA-seq database analysis, and ranked expression stability using statistical algorithms GeNorm, NormFinder, BestKeeper and ReFinder. Finally, The nine genes related to the anthocyanin synthesis pathway of Euscaphis konishii were used to verify the suitability of reference gene. Results. The results showed that the stability of EkUBC23, EkCYP38 and EkGAPDH2 was better, and the low expression reference genes (EkUBC23 and EkCYP38) were favourable for quantifying low expression target genes, while the high expression reference gene (EkGAPDH2) was beneficial for quantifying high expression genes. In this study, we present the suitable reference genes for fruit development of Euscaphis konishii based on transcriptome data, our study will contribute to further studies in molecular biology and gene function on Euscaphis konishii and other closely related species. S-Q. 2020. Comprehensive transcriptome analysis of reference genes for fruit development of Euscaphis konishii. PeerJ 8:e8474 http://doi.. Coker JS, Davies E. 2004. Selection of candidate housekeeping controls in tomato plants using EST data. Biotechniques 35(4):740-749. Czechowski T, Stitt M, Altmann T, Udvardi MK, Scheible WR. 2005. Genome-wide identification and testing of superior reference genes for transcript normalization in Arabidopsis. Plant Physiology 139(1):5-17 DOI 10.1104/pp.105.063743. Derveaux S, Vandesompele J, Hellemans J. 2010. How to do successful gene expression analysis using real-time PCR. Methods 50(4):Regev A. 2011. Full length transcriptome assembly from RNA seq data without a reference genome. Nature Biotechnology Italic 29:644-652 DOI 10.1038/nbt.1883. Guo XJ, Chen LN, Yang HQ. 2018. Reference gene selection for quantitative real-time PCR in studying culm shape development of Dendrocalamus sinicus. Forest Research 31(02):120-125 SQ. 2019. Protective effect of the total triterpenes of Euscaphis konishii Hayata pericarp on bacillus Calmette-Guérin plus lipopolysaccharide-induced liver injury. LK. 2014. Reference gene selection for real-time quantitative PCR normalization in switchgrass (Panicum virgatum L.) root tissue. Journal of Agricultural Biotechnology 22(1):55-63. Kimmy AS, Patrick PE, Joshua RP. 2017. A whole-transcriptome approach to evaluating reference genes for quantitative gene expression studies: a case study in mimulus. G3 (Bethesda) 7(4):