Dioscorin is one of the major soluble proteins in yam tubers. Unlike other well-known plant storage proteins, such as patatin and sporamin, dioscorin is argued for its function as storage proteins, and the molecular mechanisms underlying its expressional complexity are little understood. In this study, we isolated five dioscorin genes from Dioscorea alata L., comprising three class A (Da-dio1, -3 and -4) and two class B (Da-dio2 and -5) isoforms. Expressions of all dioscorin genes gradually decreased in mother tubers during yam sprouting and regrowth. On the other hand, all dioscorin genes accumulated transcripts progressively with tuber development in new tubers, with Da-dio5 being the most prominent isoform. In yam leaves, the expressions of Da-dio5 were up-regulated by the treatments of five phytohormones (gibberellic acid, salicylic acid, indole-3-acetic acid, abscisic acid, and ethylene), and three abiotic stresses (high-temperature, low-temperature and drought). To further elucidate the regulatory mechanisms of Da-dio5 expressions, transgenic Arabidopsis plants harboring the Da-dio5 promoter-β-glucuronidase (GUS) fusion were generated. GUS staining showed that expressions of the Da-dio5 promoter were detected mainly in the shoot apical meristem (SAM) and hypocotyls, and enhanced by the treatments of the five hormones, and the three abiotic stresses mentioned above. These results suggest diverse roles of Da-dio5 in yam sprouting, regrowth, and tuberization, as well as in response to enviromental cues.

Kiwifruit growth and development are severely affected by various biotic and abiotic stresses, especially cold stress and the bacterial disease caused by Pseudomonas syringae pv. actinidiae (Psa). Metallothioneins (MTs) are a group of cysteine-rich proteins that play crucial roles in stress response, metal detoxification, and homeostasis in plants. However, the protective role of these MTs in kiwifruit remains to be elucidated. In the present study, four AcMT genes were identified in the Hongyang kiwifruit genome, namely, two Type 2 isoforms (AcMT2 and AcMT2a) and two Type 3 isoforms (AcMT3a and AcMT3b) located separately on four different chromosomes. The hormones and stress response cis-elements within the promoter regions of these AcMTs were characterized. It was revealed that the four AcMT genes exhibited different expression patterns in different tissues: AcMT2 and AcMT2a were expressed at much higher levels in the fruit, male flower, female flower, root, and bark, while AcMT3a was expressed mainly in the fruit and AcMT3b was expressed highly in the bark. The expression patterns of these AcMT genes after exposure to Psa infection and different phytohormones, including gibberellic acid A3(GA₃), ethylene (ET), and abscisic acid (ABA), were evaluated. It was revealed that in response to Psa infection, the main AcMTs in each tissue (those with expression levels higher compared to the other MTs in that tissue) were downregulated during the early stage in kiwifruits, followed by a recovery phase. In addition, most AcMTs were downregulated after exposure to ET and GA₃, while type 2 AcMTs (AcMT2 and AcMT2a) were upregulated after treatment with ABA. The overexpression of AcMTs in Escherichia coli presented a higher tolerance to H₂O₂, heavy metals, low temperature, and high temperature. Collectively, these findings demonstrated the protective roles of AcMTs in terms of stress resistance conferred through plant hormone-related signal pathways.

Emilia prenanthoidea (Emilia prenanthoidea DC. Prodr. (DC.), 1838) belongs to the Asteraceae family and is a popular Miao medicinal plant in Guizhou, China. It has anti-inflammatory and antitumor properties. It is often used as a medication for healing injury, clearing heat and detoxifying, boosting blood circulation and eliminating blood stasis, and lowering inflammation and diuresis. This is the first reported study on the complete chloroplast genome of E. prenanthoidea. The E. prenanthoidea chloroplast genome is 151, 406 bp long, contains a pair of inverted repeats (IRs 24,705 bp), and is separated into a large single-copy (84,010 bp) and a short single-copy (17,986 bp) region. One hundred thirty genes were predicted, including 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Nine protein-coding genes (rps16, rpoC1, atpF, petB, petD, rpl16, rpl2, ndhB, ndhA) had a single intron, two protein-coding genes (ycf3, clpP) had two, and the remainder had none. The phylogenetic analysis found Emilia prenanthoidea and Emilia sonchifolia clustered on a single branch, with Pericallis hybrida as its sister group. This study enhances our understanding of the evolutionary relationships within the Asteraceae family and provides valuable insights for developing germplasm-specific molecular markers.

Pilea notata (Pilea notata C. H. Wright_C. H. Wright, 1899) is Pilea Lindl. of Urticaceae, which is a commonly used Miao medicine in Guizhou province. The P. notata chloroplast genome is 150,979 bp, contains a pair of inverted repeats (IRs 25,743bp), and is separated by a large single-copy region (81,446bp) and a small single-copy region (18,047bp). A total of 131 genes, including 86 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis showed that P. notata, P. verrucosa and P. monilifera united as a single branch, while Pilea cadierei was defined as a sister group of this branch.