Ornamental Traits Research Articles

Heritable epigenetic modification of BpPIN1 is associated with leaf shapes in Betula pendula.

The new variety Betula pendula 'Dalecarlica' selected from Betula pendula, shows high ornamental values owing to its lobed leaf shape. In this study, to identify the genetic components of leaf shape formation, we performed bulked-segregant analysis (BSA) and molecular marker-based fine mapping to identify causal gene responsible for lobed leaves in B. pendula 'Dalecarlica'. The most significant variations associated with leaf shape were identified within the gene BpPIN1 encoding a member of PIN-FORMED family, responsible for the auxin efflux carrier. We further confirmed the hypomethylation at the promoter region promoting the expression level of BpPIN1, which cause stronger and longer veins and lobed leaf shape in B. pendula 'Dalecarlica'. These results indicated that DNA methylation at the BpPIN1 promoter region is associated with leaf shapes in Betula pendula. Our findings revealed an epigenetic mechanism of BpPIN1 in the regulation of leaf shape in birch, which could help in molecular breeding of ornamental traits.

ISSR molecular markers and anatomical structures can assist in rapid and directional screening of cold-tolerant seedling mutants of medicinal and ornamental plant in Plumbago indica L.

Plumbago indica L. is a perennial herb with ornamental and anticancer medicinal functions widely distributed in the tropics. It is affected by temperature and cannot bloom normally in colder subtropical regions, which seriously affects its ornamental value. To create low-temperature resistance mutants and enrich new germplasm resources, this study used tissue culture and chemical reagent (0.5 mmol/L NaN3) and low-temperature stress (0°C, full darkness for 48h) induction to target and screen for cold-resistance mutants. The results showed that the ISSR band polymorphism ratio of the 24 suspected mutant materials was 87.5%. The DNA profiles of the 9 mutants initially identified were altered. The content of plumbagin in the stems and leaves of the mutants was examined, and it was found that the accumulation in the leaves of the mutant SA24 could be as high as 3.84 times that of the control, which was 0.5991%. There were significant differences in the anatomical structures of roots, stems and leaves. The mutants mostly exhibited reduced root diameter (only 0.17-0.69 times that of CK), increased stem diameter (up to 2.19 times that of CK), enlarged mesophyll cells, increased thickness (up to 1.83 times that of CK) and high specificity, which are thought to be important for the different cold resistance obtained by the mutants. In the cold resistance experiment, four cold-tolerant mutants were successfully screened according to their morphological characteristics and physiological indexes, and the mutagenesis efficiency could be as high as 2.22% and did not affect the accumulation of plumbagin in their stems and leaves, even higher than CK. The responses of the screened mutants SA15, SA19, SA23 and SA24 to low temperature showed slower leaf wilting, higher light energy conversion efficiency, less accumulation of MDA content, increased enzymatic activities of antioxidant enzymes (SOD, CAT, POD) and more accumulation of soluble sugars and proline content. These characteristics are consistent with the response of cold-resistance plants to low temperatures. The cold- resistance mutants cultivated in soil were observed of agronomic and ornamental traits for one year, mainly manifested as delayed flowering and delayed entry into the senescence stage. This study provides a more rapid and accurate technique for identifying and screening cold-tolerant mutants, and lays the foundation for future experiments on the creation of new cold-resistant varieties.

Evaluation of ornamental traits of apple trees from the collection of I. V. Michurin Federal Scientific Center

Ornamental species of apple trees have gained large popularity in landscape design. The long-term work of Russian breeders has resulted in the selection of a number of ornamental apple-tree forms; however, insufficient attention has been paid to their practical implementation. At present, the Russian market is mainly represented by European varieties, which are unstable to the harsh conditions of Russian regions. The creation of adaptive varieties of ornamental apple trees with high aesthetic characteristics appears to be a relevant research task. In this work, ornamental apple tree forms for use in landscape design are evaluated using the methodology developed by V. V. Vasekha et al. (2017). Studies were conducted in the 2015-2022 period in experimental plots located in Michurinsk, Tambov Oblast. Research objects included trees planted in 2004 with a planting scheme of 6×2 m using 54-118 rootstocks. Depending on the genotype, the bud color was found to vary from white (M. sachalinensis), bright red (M. floribunda), and purple (M. purpurea pendula, Jay Darling, etc.). The new forms 7-13, 7-29, 4-100, and Nikas were characterized by large flowers over 35 mm in diameter. The leaf color varied depending on the season, from purple and red-purple in spring to green in autumn, which was typical of the majority of the studied genotypes. In summer, the genotypes having purple leaves turn red-green with the exception for the Royalty variety and M. purpurea var. aldenhamensis and M. purpurea species, whose leaves remain red until autumn. Fruits of ornamental apple trees are small, from 8 to 35 mm in diameter. Such varieties and forms, as Royalty, Profusion, M. sargentii, M. purpurea, M. floribunda, M. sachalinensis, M. Nikita floribunda, Jay Darling, Altaiskoe bagryanoe, M. floribunda, Nikas, 7-29, 7-13, and 4-100 are characterized by fruits up to 15 mm in diameter with high aesthetic characteristics. Nikas, 7-29, 7-13, and 4-100 have a columnar crown habitus, which significantly increases their ornamental value.

Arbuscular Mycorrhizae Contribute to Growth, Nutrient Uptake, and Ornamental Characteristics of Statice (Limonium sinuatum [L.] Mill.) Subject to Appropriate Inoculum and Optimal Phosphorus

With the world’s population and pollutants on the rise, it is crucial to find sustainable and environmentally friendly solutions that increase production efficiency. Organic horticulture is an effective strategy for creating a harmless and sustainable crop production system. Arbuscular mycorrhizal fungi (AMF) have been proposed as reliable biofertilizers for sustainable agriculture, and inoculum production is a rapidly expanding market. AMF can enhance plant nutrition and growth, but their efficacy varies depending on the plant species, inoculum type, and available P concentrations. This study evaluates the response of ornamental statice (Limonium sinuatum [L.] Mill.) to mycorrhizal inoculation (first factor) with Glomus mosseae (M1), G. intraradices (M2), or their mixture (M3), plus non-inoculation (M0), and varying available P concentrations (second factor) of 10 (control, P1), 20 (P2), and 40 (P3) mg kg−1 soil in greenhouse conditions in a factorial experiment based on randomized complete block design with three replications. Root colonization, growth parameters, some ornamental traits, and the absorption of P, N, K, Ca, Zn, and Fe were measured. Root colonization was estimated as 30–65% and was reduced approximately by 32.4% with increasing P concentration in the soil. The lowest colonization percentage was recorded in P3 (45.69, 39.31, and 30.18 for M1, M2, and M3, respectively). Statice plants were positively influenced by inoculation, especially with G. mosseae in moderately available P (P2), which was also confirmed by the results of the principal component analysis. Overall, inoculated plants exhibited better nutritional status, growth, and ornamental traits than non-inoculated plants. Furthermore, mycorrhization delayed the time to the flowering of statice by 12, 7, and 9 days in M1, M2, and M3, respectively, compared to non-mycorrhizal (M0) plants. In conclusion, mycorrhizal inoculation can improve the plant nutrition, growth, and ornamental value of statice by selecting appropriate inoculum and optimal P concentrations. The results of this study suggest that mycorrhizal inoculation can be effectively used in the future to increase the quantity and quality of statice production.

The Secrets of Meristems Initiation: Axillary Meristem Initiation and Floral Meristem Initiation.

The branching phenotype is an extremely important agronomic trait of plants, especially for horticultural crops. It is not only an important yield character of fruit trees, but also an exquisite ornamental trait of landscape trees and flowers. The branching characteristics of plants are determined by the periodic initiation and later development of meristems, especially the axillary meristem (AM) in the vegetative stage and the floral meristem (FM) in the reproductive stage, which jointly determine the above-ground plant architecture. The regulation of meristem initiation has made great progress in model plants in recent years. Meristem initiation is comprehensively regulated by a complex regulatory network composed of plant hormones and transcription factors. However, as it is an important trait, studies on meristem initiation in horticultural plants are very limited, and the mechanism of meristem initiation regulation in horticultural plants is largely unknown. This review summarizes recent research advances in axillary meristem regulation and mainly reviews the regulatory networks and mechanisms of AM and FM initiation regulated by transcription factors and hormones. Finally, considering the existing problems in meristem initiation studies and the need for branching trait improvement in horticulture plants, we prospect future studies to accelerate the genetic improvement of the branching trait in horticulture plants.

Analyses of a chromosome-scale genome assembly reveal the origin and evolution of cultivated chrysanthemum

Chrysanthemum (Chrysanthemum morifolium Ramat.) is a globally important ornamental plant with great economic, cultural, and symbolic value. However, research on chrysanthemum is challenging due to its complex genetic background. Here, we report a near-complete assembly and annotation for C. morifolium comprising 27 pseudochromosomes (8.15 Gb; scaffold N50 of 303.69 Mb). Comparative and evolutionary analyses reveal a whole-genome triplication (WGT) event shared by Chrysanthemum species approximately 6 million years ago (Mya) and the possible lineage-specific polyploidization of C. morifolium approximately 3 Mya. Multilevel evidence suggests that C. morifolium is likely a segmental allopolyploid. Furthermore, a combination of genomics and transcriptomics approaches demonstrate the C. morifolium genome can be used to identify genes underlying key ornamental traits. Phylogenetic analysis of CmCCD4a traces the flower colour breeding history of cultivated chrysanthemum. Genomic resources generated from this study could help to accelerate chrysanthemum genetic improvement.

Novel hybrids with floral scent between Lagerstroemia caudata and three L. indica cultivars

L. caudata, native to China, is valued for its floral fragrance while flower size and color still negatively affects their economic value. In this study, three L. indica cultivars ‘Bai Yun Ying Xia’, ‘Qiao Jia Ren’ and ‘Fen Hu Die’ with diverse flower traits were chosen to make cross with L. caudata. Finally, a total of 2832 crosses were obtained, including interspecific, backcross and self-pollination combinations between L. caudata and L. indica. Nearly 260 hybrid seedlings were survived. Hybridity was confirmed by both morphological comparison and simple sequence repeat markers (SSR) technique. All obtained interspecific seedlings were generally intermediate in morphological traits of their parents, but variable in leaf blade length, leaf blade width, leaf blade length/width ratio, flower diameter, flower claw length, petal length, flower color and floral fragrance. Our results suggested that it is possible to optimize floral fragrance of Lagerstroemia cultivars by using L. caudata and the hybrids obtained in this study. These findings could be served as the basis for the development of superior plants with unique combinations of ornamental traits.

Genome assembly, resequencing and genome-wide association analyses provide novel insights into the origin, evolution and flower colour variations of flowering cherry.

Flowering cherry is a very popular species around the world. High-quality genome resources for different elite cultivars are needed, and the understanding of their origins and the regulation of key ornamental traits are limited for this tree. Here, a high-quality chromosome-scale genome of Prunus campanulata 'Plena' (PCP), which is a native and elite flowering cherry cultivar in China, was generated. The contig N50 of the genome was 18.31 Mb, and 99.98% of its contigs were anchored to eight chromosomes. Furthermore, a total of 306 accessions of flowering cherry germplasm and six lines of outgroups were collected. Resequencing of these 312 lines was performed, and 761 267 high-quality genomic variants were obtained. The origins of flowering cherry were predicted, and these 306 accessions could be classified into three clades, A, B and C. According to phylogenetic analysis, we predicted two origins of flowering cherry. Flowering cherry in clade A originated in southern China, such as in the Himalayan Mountains, while clades B and C originated in northeastern China. Finally, a genome-wide association study of flower colour was performed for all 312 accessions of flowering cherry germplasm. A total of seven quantitative trait loci (QTLs) were identified. One gene encoding glycosylate transferase was predicted as the candidate gene for one QTL. Taken together, our results provide a valuable genomic resource and novel insights into the origin, evolution and flower colour variations of flowering cherry.

Ectopic Expression of PgF3′5′H in Commercial Gypsophila paniculata Cultivar through Optimized Agrobacterium-Mediated Transformation

Gypsophila paniculata is one of the most popular cut flowers in the world whose major cultivars are blooming white. As is well known, blue flowers could be generated via the overexpression of the gene encoding flavonoid 3′5′-hydroxylase (F3′5′H) in species that naturally lack it. In this study, we established the regeneration and a genetic transformation system for the commercial cultivar ‘YX4’ of G. paniculata and introduced the F3′5′H of Platycodon grandiflorus (PgF3′5′H) successfully into ‘YX4’ using the established protocol. A total of 281 hygromycin (Hyg)-resistant plantlets were obtained, and 38 of them were polymerase chain reaction (PCR) positive, indicating a 13.5% transformation efficiency. Shoot apex without meristem was more suitable for explant due to its high regeneration capacity, and the supplement of thidiazuron (TDZ) provided the most efficient promotion of adventitious bud induction, whereas the supplement of 6-Benzyladenine (6-BA) and 1-naphthaleneacetic acid (NAA) did not affect much. Additionally, the combination of 1 day (d) pre-culture, 5 d co-culture, 10 min infection, 30 mg·L−1 additional acetosyringone (AS) supplement, and 10 mg·L−1 Hyg selection formed the optimized system for ‘YX4’ transformation. This reliable and efficient agrobacterium-mediated transformation of the valuable commercial cultivar ‘YX4’ will contribute not only to the creation and improvement of G. paniculata cultivars, but also to the function research of genes associated with important ornamental traits.

Tomateiro cereja ornamental em diferentes ambientes protegidos e materiais refletores em bancada de cultivo

ABSTRACT The study aimed to evaluate the growth of ornamental cherry tomato plants in different protected environments and reflective materials on the cultivation benches. As there were no repetitions of the protected environments, each environment was considered an experiment. In each environment, the experimental design used was completely randomized with five replications and three plants per plot. From the analysis of individual variances and evaluation of the mean squares of residues smaller than seven, the joint analysis of variance was performed (three protected environments x three reflective materials on the cultivation bench + 1 control without material). The protected environments evaluated were the agricultural greenhouse with a screen of 42-50% shading under the film, the agricultural screenhouse with a black screen of 30% shading, and the agricultural screenhouse with an aluminized screen of 35% shading. The reflective materials on the cultivation bench were Aluminet®, white Formica laminate, and red Formica laminate. The different protected environments influenced the growth of plants, and due to the lower incident light, the plants showed greater height in the agricultural greenhouse (42-50% shading). The reflective benches did not interfere with plant height but favored fruit production. The agricultural greenhouse (42-50% shading)) stands among the environments. For the reflective materials on the bench, aluminized fabric and red Formica laminate stood out, as they favored the growth of cherry tomato plants with desirable ornamental traits, such as greater fruit production.

The idiosyncratic genome of Korean long-tailed chicken as a valuable genetic resource

Today, breeds with ornamental traits such as exceptionally long tail feathers are economically valuable. However, the genetic basis of long-tail feathers is yet to be understood. To provide better understanding of long tail feathers, we sequenced Korean long-tailed chicken (KLC) genomes and compared them with genomes of other chicken breeds. We first analyzed the genome structure of KLC and its genomic relationship with other chickens and observed unique characteristics. Subsequently, we searched for genomic regions under selection. Feather keratin 1-like enriched region and several genes were found to have novel putative functions and effects on the long tail trait in KLC. Our findings support the value of KLC as a unique genetic resource and cast light on the genetic basis of long tail traits in avian species. We expect this novel knowledge to provide new genomic evidence and options for designing and implementing genetic improvements of ornamental chicken productivity through precision crossbreeding aids.

Leaf color change and photosystem function evaluation under heat treatment revealed the stress resistance variation between Loropetalum chinense and L. chinense var. rubrum.

This research mainly focused on the leaf color change and photosystem function differentiation between Loropetalum chinense and its variety L. chinense var. rubrum under heat stress, which were tightly concerned about their ornamental traits and growth. L. chinense 'Xiangnong Xiangyun' (X) and L. chinense var. rubrum 'Xiangnong Fendai' (F) and L. chinense var. rubrum 'Hei Zhenzhu' (H) were chosen to be experimented on to investigate whether leaf color morphology and pigment composition could influence the adaptability of plants to high temperature in order to select foliage plants which posses stable leaf color and better adaptability for hot regions. The plants were cultured in hot environment (40 °C/33 °C, day/night) and normal environment (25 °C/18 °C, day/night). Phenotype and anatomic observation of three cultivars were made and leaf color indices and pigment contents were measured. During the experiment, H and F gradually turned green, total anthocyanins contents significantly decreased in them, however, chlorophyll b contents increased in all three cultivars. In addition, the initial fluorescence (Fo) decreased in X, while increased in H and F. For the maximum fluorescence (Fm) and maximum photochemical efficiency of PSII (Fv/Fm), they only increased in H and decreased in both F and X. The non-photochemical chlorophyll fluorescence quenching (NPQ) also increased in H and decreased in F. For X, it increased at first then gradually decreased. The coefficient of photochemical quenching all increased at first then gradually decreased. Correlation analysis between showed that there was relatively strong connection between anthocyanins, flavonoids and chlorophyll fluorescence parameters, especially NPQ, proved anthocyanins and flavonoids might not only involved in enriching leaf color, but also interfered with the protection of photosystem. Generally speaking, we found higher anthocyanin and flavonoids content level not only dramatically enriched the leaf color of L. chinense var. rubrum cultivars, but also offered more potential antioxidant to keep their normal growth when encountered heat stress.

Genome-Wide Characterization and Analysis of bHLH Transcription Factors Related to Anthocyanin Biosynthesis in Cinnamomum camphora (‘Gantong 1’)

Cinnamomum camphora is one of the most commonly used tree species in landscaping. Improving its ornamental traits, particularly bark and leaf colors, is one of the key breeding goals. The basic helix-loop-helix (bHLH) transcription factors (TFs) are crucial in controlling anthocyanin biosynthesis in many plants. However, their role in C. camphora remains largely unknown. In this study, we identified 150 bHLH TFs (CcbHLHs) using natural mutant C. camphora 'Gantong 1', which has unusual bark and leaf colors. Phylogenetic analysis revealed that 150 CcbHLHs were divided into 26 subfamilies which shared similar gene structures and conserved motifs. According to the protein homology analysis, we identified four candidate CcbHLHs that were highly conserved compared to the TT8 protein in A. thaliana. These TFs are potentially involved in anthocyanin biosynthesis in C. camphora. RNA-seq analysis revealed specific expression patterns of CcbHLHs in different tissue types. Furthermore, we verified expression patterns of seven CcbHLHs (CcbHLH001, CcbHLH015, CcbHLH017, CcbHLH022, CcbHLH101, CcbHLH118, and CcbHLH134) in various tissue types at different growth stages using qRT-PCR. This study opens a new avenue for subsequent research on anthocyanin biosynthesis regulated by CcbHLH TFs in C. camphora.

Full-Length RNA Sequencing Provides Insights into Goldfish Evolution under Artificial Selection.

Goldfish Carassius auratus is an ideal model for exploring fish morphology evolution. Although genes underlying several ornamental traits have been identified, little is known about the effects of artificial selection on embryo gene expression. In the present study, hybrid transcriptome sequencing was conducted to reveal gene expression profiles of Celestial-Eye (CE) and Ryukin (RK) goldfish embryos. Full-length transcriptome sequencing on the PacBio platform identified 54,218 and 54,106 transcript isoforms in CE and RK goldfish, respectively. Of particular note was that thousands of alternative splicing (AS) and alternative polyadenylation (APA) events were identified in both goldfish breeds, and most of them were inter-breed specific. RT-PCR and Sanger sequencing showed that most of the predicted AS and APA were correct. Moreover, abundant long non-coding RNA and fusion genes were detected, and again most of them were inter-breed specific. Through RNA-seq, we detected thousands of differentially expressed genes (DEGs) in each embryonic stage between the two goldfish breeds. KEGG enrichment analysis on DEGs showed extensive differences between CE and RK goldfish in gene expression. Taken together, our results demonstrated that artificial selection has led to far-reaching influences on goldfish gene expression, which probably laid the genetic basis for hundreds of goldfish variations.

Metabolic profile and transcriptome reveal the mystery of petal blotch formation in rose

BackgroundPetal blotch is a unique ornamental trait in angiosperm families, and blotch in rose petal is rare and has great esthetic value. However, the cause of the formation of petal blotch in rose is still unclear. The influence of key enzyme genes and regulatory genes in the pigment synthesis pathways needs to be explored and clarified.ResultsIn this study, the rose cultivar ‘Sunset Babylon Eyes’ with rose-red to dark red blotch at the base of petal was selected as the experimental material. The HPLC-DAD and UPLC-TQ-MS analyses indicated that only cyanidin 3,5-O-diglucoside (Cy3G5G) contributed to the blotch pigmentation of ‘Sunset Babylon Eyes’, and the amounts of Cy3G5G varied at different developmental stages. Only flavonols but no flavone were found in blotch and non-blotch parts. As a consequence, kaempferol and its derivatives as well as quercetin and its derivatives may act as background colors during flower developmental stages. Despite of the differences in composition, the total content of carotenoids in blotch and non-blotch parts were similar, and carotenoids may just make the petals show a brighter color. Transcriptomic data, quantitative real-time PCR and promoter sequence analyses indicated that RC7G0058400 (F3’H), RC6G0470600 (DFR) and RC7G0212200 (ANS) may be the key enzyme genes for the early formation and color deepening of blotch at later stages. As for two transcription factor, RC7G0019000 (MYB) and RC1G0363600 (WRKY) may bind to the promoters of critical enzyme genes, or RC1G0363600 (WRKY) may bind to the promoter of RC7G0019000 (MYB) to activate the anthocyanin accumulation in blotch parts of ‘Sunset Babylon Eyes’.ConclusionsOur findings provide a theoretical basis for the understanding of the chemical and molecular mechanism for the formation of petal blotch in rose.

Ispravka: Efekat godine na morfološka i ornamentalna svojstva stepskog božura (2023, vol 32, broj 1, str. 65-72)

The Editorial Board of "Acta herbologica" journal, in agreement with authors (Prijić Željana, Marković Tatjana, Radanović Dragoja, Jingqi Xue, Xiuxin Zhang, Gordanić Stefan, Mikić Sara, Dragumilo Ana, Čutović Natalija, Batinić Petar) of the paper "The effect of the year on the steppe peony's morphological and ornamental traits" (Vol 32, No 1, p. 65-72, 2023) who pointed out the technical errors that occurred after the paper was published, made the decision to do the necessary corrections in accordance with the prescribed procedure. We apologize the authors for errors that occurred in published paper and thank them for assistance in detecting them. According to that, the appropriate correction was made.

Diversity, classification, and EST‐SSR‐based association analysis of caladium ornamental traits

Caladium (Caladium × Hortulanum Birdsey) is a popular ornamental plant with a wide range of vibrant leaf color among Araceae. Even after years of breeding, creating new caladium leaf color variations is extremely difficult. Molecular marker-assisted selection is an effective approach for accelerating breeding, but few studies on the molecular markers associated with caladium traits have been performed. In the current study, 144 caladium accessions were used to examine 12 phenotypic characteristics. The coefficient of variation for four numerical characters ranged from 23.94% to 43.22%, and the Shannon-Wiener indexes for eight descriptive characters ranged from 0.13 to 1.52. Based on L*, a*, b*, C, h° values determined by a colorimeter and hierarchical cluster analysis, the leaf color can be divided into four groups: pale green, green, light pink, and red. Furthermore, 7708 new SSR loci were identified by transcriptome sequencing, and 26 SSR markers with high polymorphism and reproducibility were screened. Genetic structure, NJ clustering, and PCoA analysis revealed that 144 accessions could be divided into three clusters, with genetic structure being closely related to germplasm origin. An association analysis revealed that the SSR markers 2, 1, 1, 1, 1, and 1 were mainly associated with petiole color, main vein color, blade upperside glossiness, and C, b*, and L* of leaf color (p < 0.01). These findings will serve as a valuable reference for evaluating germplasm resources and caladium molecular marker-assisted breeding.

A WRKY Transcription Factor PmWRKY57 from Prunus mume Improves Cold Tolerance in Arabidopsis thaliana.

Prunus mume, a woody perennial tree, is valued for its ornamental traits and has been cultivated for a long history. Low temperature is the main environmental factor restricting the distribution and affecting the growth of P. mume. In plants, some WRKY transcription factors have been reported to participate in regulating cold tolerance. However, there were few researches about functional characterization of WRKYs involving in P. mume cold response. Here, a cold-induced WRKY gene named as PmWRKY57 was cloned from a P. mume cultivar 'Guhong Zhusha.' PmWRKY57 protein harboring a WRKY domain and a C2H2 zinc finger motif belongs to Group IIc of WRKY family. The PmWRKY57 protein was located to the nucleus and has transcriptional activation activity. PmWRKY57-overexpresing Arabidopsis thaliana lines showed improved cold tolerance, compared to wild-type plants. Under cold treatment, the leaves of transgenic lines contained significantly lower malondialdehyde content, and higher levels of superoxide dismutase activity, peroxidase activity, and proline content than wild-type plants. Furthermore, the expression levels of cold-response genes such as AtCOR6.6, AtCOR47, AtKIN1, and AtRCI2A were up-regulated in leaves of transgenic A. thaliana compared to those in wild-type plants. This study characterized the function of PmWRKY57 in improving cold tolerance of plants.

Transcriptome Analysis Reveals the Molecular Mechanisms Associated with Flower Color Formation in Camellia japonica ‘Joy Kendrick’

Camellia japonica is a woody flower with high ornamental and economic value used for landscaping and as a pot plant. Floral colors are among the most important ornamental traits of flower plants, particularly multicolored flowers. The C. japonica cultivar ‘Joy Kendrick’ has multicolored flowers; the corolla is pink with darker red stripes, but the molecular mechanism underlying this trait is unknown. Here, pigment analysis showed that there are more anthocyanins accumulate in red petal regions than in pink areas, which may be key to formation of red stripes. Furthermore, transcriptome analysis revealed that anthocyanin biosynthesis, modification, and transporter genes are highly expressed in red stripes, consistent with the observed anthocyanin accumulation. In addition, many plant hormone signal transduction genes, particularly auxin, may contribute to the regulation of red stripe formation. This study provides broad insights into pigment accumulation and the regulatory mechanisms underlying floral color formation in C. japonica, and lays a foundation for breeding new C. japonica varieties.

Syringa oblata genome provides new insights into molecular mechanism of flower color differences among individuals and biosynthesis of its flower volatiles.

Syringa oblata is a high ornamental value tree owing to its elegant colors, unique aromas and wide adaptability, however, studies on the molecular mechanism underlying the formation of its ornamental traits are still lacking. Here, we presented a chromosome-scale genome assembly of S. oblata and the final genome size was 1.11 Gb with a contig N50 of 4.75 Mb, anchored on 23 chromosomes and was a better reference for S. oblata transcriptome assembly. Further by integrating transcriptomic and metabolic data, it was concluded that F3H, F3'H, 4CL and PAL, especially the F3'H, were important candidates involved in the formation of floral color differences among S. oblata individuals. Genome-wide identification and analysis revealed that the TPS-b subfamily was the most abundant subfamily of TPS family in S. oblata, which together with the CYP76 family genes determined the formation of the major floral volatiles of S. oblata. Overall, our results provide an important reference for mechanistic studies on the main ornamental traits and molecular breeding in S. oblata.