Ginger (Zingiber officinale Rosc.) is an important spice crop valued for its flavored and medical properties. It is susceptible to soil-borne diseases, which can cause considerable economic loss to growers. In vitro culture is feasible for the propagation of disease-free ginger plants, but has several disadvantages when producing seed rhizomes that can be commercially used, such as long cultivation cycles (usually 2–3 years) and occurrence of somaclonal variation. In this study, dynamic changes in the morphological characteristics of in vitro-propagated disease-free plants of ‘Wuling’ ginger were evaluated by continuous observation and measurement at 30-day intervals, and morphological variants were screened and characterized by agronomic, cytological, and molecular analysis at harvest. Results showed that the plants grew rapidly within 120 days after planting, and the most active growth period was from 60 to 120 days. Eight plants with clear and stable morphological differences were screened out from approximately 2000 plants grown in the field, and they could be classified into two groups (VT1 and VT2) based on tiller number, plant height, leaf color, and leaf shape. By flow cytometry analysis and chromosome counting, the VT1 was confirmed to be diploid, with the shortest plant height, the largest number of tillers and rhizome knobs, and the smallest tiller diameter and rhizome size among the three types of plants. The VT2 was mixoploid, consisting of diploid and tetraploid cells, with significantly reduced tiller number and rhizome knobs, significantly larger stomatal guard cells/apertures, and significantly lower stomatal density. SSR analysis detected DNA band profile changes in six out of the eight variants, including one plant of the VT1 and all the VT2 plants. The findings of this study might contribute to the commercial production of disease-free seed rhizomes in ginger, and the characterized somaclonal variants could provide useful germplasm resources for future breeding.

Ginger (Zingiber officinale Roscoe), a widely consumed edible and medicinal plant, possesses significant nutritional and economic value. Abiotic stresses such as drought and low temperatures can impact the growth and development of ginger. The plant-specific transcription factor Teosinte branched1/cycloidea/proliferating cell factor (TCP) has progressively been identified in various plants for its role in regulating plant growth and development as well as conferring resistance to abiotic stresses. However, limited information on the TCP family is available in ginger. In this study, we identified 20 TCP members in the ginger genome, which were randomly distributed across 9 chromosomes. Based on phylogenetic analysis, these ginger TCP were classified into two subfamilies: Class I (PCF) and Class II (CIN, CYC/TB). The classification of the identified ginger TCPs was supported by a multi-species phylogenetic tree and motif structure analysis, suggesting that the amplification of the ginger TCP gene family occurred prior to the differentiation of angiosperms. The promoter region of ginger TCP genes was found to contain numerous cis-acting elements associated with plant growth, development, and abiotic stress response. Among these elements, the stress response element, anaerobic induction, and MYB binding site play a dominant role in drought responsiveness. Additionally, expression pattern analysis revealed variations in the expression of ginger TCP gene among different tissues and in response to diverse abiotic stresses (drought, low temperature, heat, and salt). Our research offers a thorough examination of TCP members within the ginger plant. This analysis greatly contributes to the understanding of how TCP genes regulate tissue development and response to stress, opening up new avenues for further exploration in this field.

GRAS family proteins are one of the most abundant transcription factors in plants; they play crucial roles in plant development, metabolism, and biotic- and abiotic-stress responses. The GRAS family has been identified and functionally characterized in some plant species. However, this family in ginger (Zingiber officinale Roscoe), a medicinal crop and non-prescription drug, remains unknown to date. In the present study, 66 GRAS genes were identified by searching the complete genome sequence of ginger. The GRAS family is divided into nine subfamilies based on the phylogenetic analyses. The GRAS genes are distributed unevenly across 11 chromosomes. By analyzing the gene structure and motif distribution of GRAS members in ginger, we found that the GRAS genes have more than one cis-acting element. Chromosomal location and duplication analysis indicated that whole-genome duplication, tandem duplication, and segmental duplication may be responsible for the expansion of the GRAS family in ginger. The expression levels of GRAS family genes are different in ginger roots and stems, indicating that these genes may have an impact on ginger development. In addition, the GRAS genes in ginger showed extensive expression patterns under different abiotic stresses, suggesting that they may play important roles in the stress response. Our study provides a comprehensive analysis of GRAS members in ginger for the first time, which will help to better explore the function of GRAS genes in the regulation of tissue development and response to stress in ginger.

Aneuploids are valuable materials of genetic diversity for genetic analysis and improvement in diverse plant species, which can be propagated mainly via in vitro culture methods. However, somaclonal variation is common in tissue culture-derived plants including euploid caladium. In the present study, the genetic stability of in vitro-propagated plants from the leaf cultures of two types of caladium (Caladium × hortulanum Birdsey) aneuploids obtained previously was analyzed morphologically, cytologically, and molecularly. Out of the randomly selected 23 and 8 plants regenerated from the diploid aneuploid SVT9 (2n = 2x − 2 = 28) and the tetraploid aneuploid SVT14 (2n = 4x − 6 = 54), respectively, 5 plants from the SVT9 and 3 plants from the SVT14 exhibited morphological differences from their corresponding parent. Stomatal analysis indicated that both the SVT9-derived variants and the SVT14-originated plants showed significant differences in stomatal guard cell length and width. In addition, the variants from the SVT14 were observed to have rounder and thicker leaves with larger stomatal guard cells and significantly reduced stomatal density compared with the regenerants of the SVT9. Amongst the established plants from the SVT9, two morphological variants containing 3.14–3.58% less mean fluorescence intensity (MFI) lost one chromosome, and four variants containing 4.55–11.02% more MFI gained one or two chromosomes. As for the plants regenerated from the SVT14, one variant with significantly higher MFI gained two chromosomes and three plants having significantly lower MFI resulted in losing four chromosomes. Three, out of the twelve, simple sequence repeat (SSR) markers identified DNA band profile changes in four variants from the SVT9, whereas no polymorphism was detected among the SVT14 and its regenerants. These results indicated that a relatively high frequency of somaclonal variation occurred in the in vitro-propagated plants from caladium aneuploids, especially for the tetraploid aneuploid caladium. Newly produced aneuploid plants are highly valuable germplasm for future genetic improvement and research in caladium.

Ginger is a valuable crop known for its nutritional, seasoning, and health benefits. However, abiotic stresses, such as high temperature and drought, can adversely affect its growth and development. Heat shock transcription factors (HSFs) have been recognized as crucial elements for enhancing heat and drought resistance in plants. Nevertheless, no previous study has investigated the HSF gene family in ginger. In this research, a total of 25 ZoHSF members were identified in the ginger genome, which were unevenly distributed across ten chromosomes. The ZoHSF members were divided into three groups (HSFA, HSFB, and HSFC) based on their gene structure, protein motifs, and phylogenetic relationships with Arabidopsis. Interestingly, we found more collinear gene pairs between ZoHSF and HSF genes from monocots, such as rice, wheat, and banana, than dicots like Arabidopsis thaliana. Additionally, we identified 12 ZoHSF genes that likely arose from duplication events. Promoter analysis revealed that the hormone response elements (MEJA-responsiveness and abscisic acid responsiveness) were dominant among the various cis-elements related to the abiotic stress response in ZoHSF promoters. Expression pattern analysis confirmed differential expression of ZoHSF members across different tissues, with most showing responsiveness to heat and drought stress. This study lays the foundation for further investigations into the functional role of ZoHSFs in regulating abiotic stress responses in ginger.

Background: Zingiber Mill., a morphologically diverse herbaceous perennial genus of Zingiberaceae, is distributed mainly in tropical to warm-temperate Asia. In China, species of Zingiber have crucial medicinal, edible, and horticultural values; however, their phylogenetic relationships remain unclear. Methods: To address this issue, the complete plastomes of the 29 Zingiber accessions were assembled and characterized. Comparative plastome analysis and phylogenetic analysis were conducted to develop genomic resources and elucidate the intraspecific phylogeny of Zingiber. Results: The newly reported plastomes ranged from 161,495 to 163,880 bp in length with highly conserved structure. Results of comparative analysis suggested that IR expansions/contractions and changes of repeats were the main reasons that influenced the genome size of the Zingiber plastome. A large number of SSRs and six highly variable regions (rpl20, clpP, ycf1, petA-psbJ, rbcL-accD, and rpl32-trnL) have been identified, which could serve as potential DNA markers for future population genetics or phylogeographic studies on this genus. The well-resolved plastome phylogeny suggested that Zingiber could be divided into three clades, corresponding to sect. Pleuranthesis (sect. Zingiber + sect. Dymczewiczia) and sect. Cryptanthium. Conclusions: Overall, this study provided a robust phylogeny of Zingiber plants in China, and the newly reported plastome data and plastome-derived markers will be of great significance for the accurate identification, protection, and agricultural management of Zingiber resources in the future.