Camellia hainingii S.X.Yang et Y.S. Huang, a new species from Guangxi, China, is described and illustrated. It is morphologically similar to C. pachyandra Hu but can be easily distinguished from the latter by its glabrous leaf blade (vs. pubescent along the midvein abaxially), glabrous (vs. pubescent) petiole, bracteoles and sepals 9–11 (vs. 6) with dense pubescent (vs. glabrous) on the inner face, stamens 80–110 (vs. 40–50), slender (vs. thickening) inner filaments, glabrous (vs. dense tomentum) ovary and furfuraceous (vs. smooth) pericarp. The conservation status of this new species was assessed as Critically Endangered (CR).

The plant U-box (PUB) gene family, one of the major ubiquitin ligase families in plants, plays important roles in multiple cellular processes including environmental stress responses and resistance. The function of U-box genes has been well characterized in Arabidopsis and other plants. However, little is known about the tea plant (Camellia sinensis) PUB genes. Here, 89 U-box proteins were identified from the chromosome-scale referenced genome of tea plant. According to the domain organization and phylogenetic analysis, the tea plant PUB family were classified into ten classes, named Class I to X, respectively. Using previously released stress-related RNA-seq data in tea plant, we identified 34 stress-inducible CsPUB genes. Specifically, eight CsPUB genes were expressed differentially under both anthracnose pathogen and drought stresses. Moreover, six of the eight CsPUBs were upregulated in response to these two stresses. Expression profiling performed by qRT-PCR was consistent with the RNA-seq analysis, and stress-related cis-acting elements were identified in the promoter regions of the six upregulated CsPUB genes. These results strongly implied the putative functions of U-box ligase genes in response to biotic and abiotic stresses in tea plant.

Golden camellia flowers are treasured for their unique yellow color and bioactive chemical compounds. Because of its high market demand, there is strong interest in inducing early flowering in golden camellias for earlier harvest. Previously, we have successfully induced flowering in Camelia chrysantha (Hu) Tuyama juvenile grafted plants and seedlings with paclobutrazol (PBZ). During this study, we investigated the efficacy of PBZ on C. tamdaoensis juvenile rooted cuttings. C. tamdaoensis is a yellow-flowering camellia species that is native to Vietnam and valued by the local population. It was found that applications of 100 and 200 ppm PBZ generated an average of 13 and 30 flowers per 5-year-old plant, respectively. None of the control plants flowered. The average flower diameter was 17.2 cm for 100-ppm-induced flowers and 26.0 cm for 200-ppm-induced flowers. The dynamics of various phytohormones (indoleacetic acid, abscisic acid, salicylic acid, and jasmonic acid) were altered by PBZ treatment. It is suggested that low indoleacetic acid, high abscisic acid, and jasmonic acid and a gradual increase in salicylic acid benefit floral initiation of golden camellias. The study provided the first insight regarding the action mechanism of PBZ for the initiation of camellia flowering.

Camellia piloflora, a new yellow camellia from southwestern Guangxi, China, is described and illustrated. Morphologically, it is closest related to C. debaoensis, but differs by its puberulent sepals, pubescent filaments, and tomentose ovary and style.

Camellia zhaiana S.X. Yang (Theaceae) is a recently described species reported from Guangxi, China. It was proposed as a critically endangered species according to the IUCN Red List Categories and Criteria. In this study, we report and characterize the complete chloroplast (cp) genome of C. zhaiana using Illumina pair-end sequencing data. This is the first report of a cp genome of a species classified in Camellia section. Longipedicellata. The cp genome of C. zhaiana is 156,627 bp in length and includes a large single-copy region (LSC, 86,196 bp), a small single-copy region (SSC, 18,281 bp), and a pair of inverted repeat regions (IRs, 26,075 bp). The genome contains 135 genes, including 40 tRNA, eight rRNA, and 87 protein-coding genes. Phylogenetic analysis showed a strongly supported sister relationship between C. zhaiana and C. longipedicellata, which is a species classified in sect. Longipedicellata. These data support the previous systematic findings of C. zhaiana and advance the bioinformatics of the genus Camellia.

On the basis of field investigation and herbarium specimen examination, Tutcheria multisepala, Pyrenaria poilaneana, Parapyrenaria indochinensis and Camellia luuana are treated to the synonymy of Pyrenaria jonquieriana. In addition, lectotypes are designated for the names Pyrenaria jonquieriana and Pyrenaria poilaneana.