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Polygonatum cyrtonema Hua is valued both as a precious traditional Chinese medicinal herb and as a prime example of a plant that bridges medicinal and culinary applications. Renowned for its significant medicinal and edible qualities, this botanical exemplifies a unique convergence of therapeutic and nutritional benefits. However, the primary rhizome of Polygonatum cyrtonema Hua development is difficult to germinate into seedlings in the same year. The germination of primary rhizome buds of P. cyrtonema can be promoted by treatment with exogenous hormone 6-BA, but the related regulatory mechanism is not clear. In this study, we found that the cytokinin oxidase (CKX) plays a key role in the germination of primary rhizome buds of P. cyrtonema . PcCKX1,2,3 promoted the expression of dormancy positively regulated genes, and repressed the expression of dormancy negatively regulated genes, which in turn inhibited Arabidopsis seed germination, and PcCKX2 was the major gene. PcCKX1,2,3 promoted the expression of dormant positively regulated genes such as sweet potato IbZEP, IbNCED3, IbDOG1, IbABI5, IbCKX3 , and IbCKX7, which in turn delayed the sprouting of sweet potato rhizomes, and that PcCKX2 played a major role. We further screened three MYB transcription factors significantly associated with PcCKX1,2,3 . Yeast one-hybrid, Dual-LUC, and EMSA experiments showed that PcMYB4, PcKUA1, and PcCSA all bind to and repress the expression of elements of the PcCKX1,2,3 promoter. Heterologous transformation of Arabidopsis experiments showed that PcMYB4, PcKUA1 , and PcCSA repressed the expression of dormancy-associated genes such as DOG1 , NCED3 , ABI5 , CKX3 , and CKX7 , which, in turn, facilitated Arabidopsis seed germination. Taken together, we found that PcMYBs are involved in the transcriptional regulation of PcCKXs to promote the germination of primary rhizome buds of P. cyrtonema . The results of this study lay the foundation for analyzing the molecular mechanism of primary rhizome bud germination in P. cyrtonema .

Polygonatum sibiricum (P. sibiricum) rhizomes are widely used as a tonic and functional food, and are often processed to enhance their tonic function by repeated steaming and drying. As the most important constituent, the polysaccharide from P. sibiricum rhizomes (PSP) has demonstrated various activities, but the alteration of structural characteristics and activities of the purified PSPs during steaming process was rarely investigated. To well understand the effect of steaming process on the polysaccharides of P. sibiricum, neutral polysaccharides from P. sibiricum rhizomes (PSP0 ~ PSP9) after steaming were first isolated and purified, and then the chemical properties and antioxidant activities were determined. The results showed that the molar ratios of monosaccharides in PSPs were different. The molecular weights of PSPs were increased significantly after the fourth steaming. Morphological studies showed that the surface of PSPs became much tighter during the steaming process. Fourier transform infrared spectroscopy spectra displayed the polysaccharides had similar backbones and chemical groups. Furthermore, the antioxidant activity of PSPs was measured through radical scavenging tests. It was found that the radical scavenging activity of PSPs was elevated strikingly after steaming, and increased gradually with numbers of steaming process. The biological and chemical variance of PSPs revealed considerable segregation of PSP0, PSP1 ~ PSP4 and PSP5 ~ PSP9. In conclusion, our results proposed the fourth time as the optimal number of steaming to extract functional polysaccharide from P. sibiricum rhizomes.

Summary Rhizomes are modified stems that grow underground and produce new individuals genetically identical to the mother plant. Recently, a breakthrough has been made in efforts to convert annual grains into perennial ones by utilizing wild rhizomatous species as donors, yet the developmental biology of this organ is rarely studied. Oryza longistaminata, a wild rice species featuring strong rhizomes, provides a valuable model for exploration of rhizome development. Here, we first assembled a double‐haplotype genome of O. longistaminata, which displays a 48‐fold improvement in contiguity compared to the previously published assembly. Furthermore, spatiotemporal transcriptomics was performed to obtain the expression profiles of different tissues in O. longistaminata rhizomes and tillers. Two spatially reciprocal cell clusters, the vascular bundle 2 cluster and the parenchyma 2 cluster, were determined to be the primary distinctions between the rhizomes and tillers. We also captured meristem initiation cells in the sunken area of parenchyma located at the base of internodes, which is the starting point for rhizome initiation. Trajectory analysis further indicated that the rhizome is regenerated through de novo generation. Collectively, these analyses revealed a spatiotemporal transcriptional transition underlying the rhizome initiation, providing a valuable resource for future perennial crop breeding.

Root–nodule symbiosis between leguminous plants and nitrogen-fixing bacteria (rhizobia) involves molecular communication between the two partners. Key components for the establishment of symbiosis are rhizobium-derived lipochitooligosaccharides (Nod factors; NFs) and their leguminous receptors (NFRs) that initiate nodule development and bacterial entry. Here we demonstrate that the soybean microsymbiont Bradyrhizobium elkanii uses the type III secretion system (T3SS), which is known for its delivery of virulence factors by pathogenic bacteria, to promote symbiosis. Intriguingly, wild-type B. elkanii , but not the T3SS-deficient mutant, was able to form nitrogen-fixing nodules on soybean nfr mutant En1282. Furthermore, even the NF-deficient B. elkanii mutant induced nodules unless T3SS genes were mutated. Transcriptional analysis revealed that expression of the soybean nodulation-specific genes ENOD40 and NIN was increased in the roots of En1282 inoculated with B. elkanii but not with its T3SS mutant, suggesting that T3SS activates host nodulation signaling by bypassing NF recognition. Root-hair curling and infection threads were not observed in the roots of En1282 inoculated with B. elkanii , indicating that T3SS is involved in crack entry or intercellular infection. These findings suggest that B. elkanii has adopted a pathogenic system for activating host symbiosis signaling to promote its infection.

Despite long-time awareness of the importance of the location of buds in plant biology, research on belowground bud banks has been scant. Terms such as lignotuber, xylopodium and sobole, all referring to belowground bud-bearing structures, are used inconsistently in the literature. Because soil efficiently insulates meristems from the heat of fire, concealing buds below ground provides fitness benefits in fire-prone ecosystems. Thus, in these ecosystems, there is a remarkable diversity of bud-bearing structures. There are at least six locations where belowground buds are stored: roots, root crown, rhizomes, woody burls, fleshy swellings and belowground caudexes. These support many morphologically distinct organs. Given their history and function, these organs may be divided into three groups: those that originated in the early history of plants and that currently are widespread (bud-bearing roots and root crowns); those that also originated early and have spread mainly among ferns and monocots (nonwoody rhizomes and a wide range of fleshy underground swellings); and those that originated later in history and are strictly tied to fire-prone ecosystems (woody rhizomes, lignotubers and xylopodia). Recognizing the diversity of belowground bud banks is the starting point for understanding the many evolutionary pathways available for responding to severe recurrent disturbances.

Bamboo (Phyllostachys praecox) is one of the largest members of the grass family Poaceae, and is one of the most economically important crops in Asia. However, complete knowledge of bamboo development and its molecular mechanisms is still lacking. In the present study, the differences in anatomical structure among rhizome buds, rhizome shoots, and bamboo shoots were compared, and several genes related to the development of the bamboo rhizome bud were identified. The rice cross-species microarray hybridization showed a total of 318 up-regulated and 339 down-regulated genes, including those involved in regulation and signalling, metabolism, and stress, and also cell wall-related genes, in the bamboo rhizome buds versus the leaves. By referring to the functional dissection of the homologous genes from Arabidopsis and rice, the putative functions of the 52 up-regulated genes in the bamboo rhizome bud were described. Six genes related to the development of the bamboo rhizome bud were further cloned and sequenced. These show 66-90% nucleotide identity and 68-98% amino acid identity with the homologous rice genes. The expression patterns of these genes revealed significant differences in rhizome shoots, rhizome buds, bamboo shoots, leaves, and young florets. Furthermore, in situ hybridization showed that the PpRLK1 gene is expressed in the procambium and is closely related to meristem development of bamboo shoots. The PpHB1 gene is expressed at the tips of bamboo shoots and procambium, and is closely related to rhizome bud formation and procambial development. To our knowledge, this is the first report that uses rice cross-species hybridization to identify genes related to bamboo rhizome bud development, and thereby contributes to the further understanding of the molecular mechanism involved in bamboo rhizome bud development.

Efficient artificial lighting is essential for optimizing plant growth and propagation in closed-type smart farms. This study aimed to evaluate the effects of light-emitting diode (LED) combinations using red (R), blue (B), and white (W) light on physiological responses and rhizome-based vegetative propagation in Dysophylla yatabeana , a poorly seed-propagable aquatic species. Plants were cultivated under five different spectral treatments and a natural light control. Key physiological indicators—including net photosynthetic rate (P n ), substomatal CO 2 partial pressure (C i ), transpiration rate (E), photo-synthetic quantum efficiency (Φ), and leaf-to-air temperature difference (ΔT)—were measured. Path analysis was conducted to clarify the direct and indirect relationships among these variables and growth traits such as shoot dry weight (SDW), rhizome dry weight (RDW), and number of rhizomes (RN). The addition of W significantly enhanced both SDW and RN, whereas high R: B ratios increased P n but suppressed RDW. Light quality was found to influence growth not only through direct spectral effects but also via complex physiological pathways regulating internal CO 2 dynamics and assimilate allocation. These results provide insight into light management strategies for controlled-environment agriculture, especially for species requiring vegetative propagation, and support the development of sustainable indoor cultivation systems using LED lighting.

Maintaining genetic fidelity in in vitro-regenerated plants derived from chimeric tissues presents a significant challenge during tissue culture experiments. Sansevieria trifasciata cv. Laurentii exhibits striking periclinal chimeric tissues along its leaves, which are compromised when propagating plants through leaf cuttings. In addition to establishing in vitro production of S. trifasciata cv. Laurentii, the regeneration efficiency of light exposed single-node rhizome explants was also evaluated. Among various types of rhizome explants, the single-node rhizome explant produced the highest mean number of shoots per explant (2.5) on MS medium supplemented with 3 mg L − 1 BA and 0.1 mg L − 1 NAA, which was approximately five times higher than that of other explants. Notably, all regenerated plants originating from nodal and terminal meristems were morphologically similar to their corresponding mother plants and retained their chimeric characteristics. In contrast, shoots derived from explants containing both nodal segments and terminal meristems (MN explants) exhibited some degree of morphological variation. Specifically, higher concentrations of BA (6 mg L − 1 ) were found to decrease the phenotypic stability of regenerated shoots by 50%. De novo rhizomes derived from light exposed single-node rhizome (NC explants) yielded the highest mean number of shoots (6 shoot per explant) on MS medium supplemented with 4 mg L − 1 NAA and either 0.5 or 0.35 mg L − 1 BA. Shoots from de novo rhizomes closely resembled the mother plants, while callus-derived shoots showed only 65% similarity. The presence of light-influenced elevated sugar levels in NC explants supports the hypothesis that the enhanced regeneration capacity in light-exposed single-node rhizome tissues is likely attributed to the upregulation of cytokinin synthesis-related genes and light-induced carbohydrate allocation, which alters hormonal homeostasis and triggers the mitotic activities necessary for de novo rhizome regeneration and shoot multiplication.

Background Caucasian clover ( Trifolium ambiguum M. Bieb.) is a strongly rhizomatous, low-crowned perennial leguminous and ground-covering grass. The species may be used as an ornamental plant and is resistant to cold, arid temperatures and grazing due to a well-developed underground rhizome system and a strong clonal reproduction capacity. However, the posttranscriptional mechanism of the development of the rhizome system in caucasian clover has not been comprehensively studied. Additionally, a reference genome for this species has not yet been published, which limits further exploration of many important biological processes in this plant. Result We adopted PacBio sequencing and Illumina sequencing to identify differentially expressed genes (DEGs) in five tissues, including taproot (T1), horizontal rhizome (T2), swelling of taproot (T3), rhizome bud (T4) and rhizome bud tip (T5) tissues, in the caucasian clover rhizome. In total, we obtained 19.82 GB clean data and 80,654 nonredundant transcripts were analysed. Additionally, we identified 78,209 open reading frames (ORFs), 65,227 coding sequences (CDSs), 58,276 simple sequence repeats (SSRs), 6821 alternative splicing (AS) events, 2429 long noncoding RNAs (lncRNAs) and 4501 putative transcription factors (TFs) from 64 different families. Compared with other tissues, T5 exhibited more DEGs, and co-upregulated genes in T5 are mainly annotated as involved in phenylpropanoid biosynthesis. We also identified betaine aldehyde dehydrogenase ( BADH ) as a highly expressed gene-specific to T5. A weighted gene co-expression network analysis (WGCNA) of transcription factors and physiological indicators were combined to reveal 11 hub genes (MEgreen-GA3), three of which belong to the HB-KNOX family, that are up-regulated in T3. We analysed 276 DEGs involved in hormone signalling and transduction, and the largest number of genes are associated with the auxin (IAA) signalling pathway, with significant up-regulation in T2 and T5. Conclusions This study contributes to our understanding of gene expression across five different tissues and provides preliminary insight into rhizome growth and development in caucasian clover.

Oleoresin, a product derived from ginger rhizomes, contains a high concentration of active compounds and has the potential to be used not only as a medicine but also as a beneficial natural ingredient material to the human body. Ginger oleoresin is a valuable product that contains a variety of compounds and provides functional health benefits as well as immunity boosters to large groups of people. Gingerol is a key ingredient in ginger rhizome oleoresin extract. Gingerol (C17H26O4) is a compound found in ginger oleoresin that easily decomposes into Shogaols (C17H24O3). The ethanolic extract of zingiber rhizomes powder was processed with the best yield of oleoresin of 38.313% and concentration of [6]-gingerol of 0.39 mg/g extract, which was produced in 120 minutes at a temperature of 60 0C. While the best [6]-gingerol content in oleoresin was 1.33 mg/g extract with a ginger oleoresin yield of 21.821% produced under 50 0C extraction temperature in 60 minutes.