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Bermudagrass (Cynodon spp.) is a drought-resistant warm-season turfgrass adapted to the southern and transitional zones in the United States. Multiple hybrid cultivars have been developed and released for use as turfgrass, and others are still undergoing development. Increasing genetic diversity of commercial cultivars is vital to stress tolerance. A DNA profiling study of 21 experimental selections from the Oklahoma State University turfgrass breeding program and 11 cultivars was conducted using 51 simple sequence repeat primer pairs across the bermudagrass genome. A pairwise genetic relationship analysis of the genotypes using 352 polymorphic bands showed genetic similarity coefficients ranging from 0.59 to 0.89. The average pairwise population differentiation values were 0.012 for the 11 cultivars and 0.169 for the 21 selections. A cluster analysis using the unweighted paired group with the arithmetic average method grouped the entries into six clusters. A correlation analysis identified different levels of pairwise genetic relationships among the entries that largely reflected parental relationship. Directional breeding and selection for cold hardiness or drought resistance created progeny that had distinct genetic diversity in the tested bermudagrasses. It is evident that an increase in genetic diversity of the existing cultivar pool with the release of one or more experimental selections for commercial use will strengthen and improve bermudagrass systems.
The calla lily (Zantedeschia hybrida) is a valued ornamental plant due to its unique shape and color variations. To determine the mechanisms responsible for color development in the calla lily spathe, we conducted a comparative transcriptomic analysis of the spathes of the black [Black Girl (B)], pink [Romantic (P)], and white [Ventura (W)] cultivars. The gene expression patterns in six spathe colors, including the preceding three colors as well as the amaranth [Promise (N)], red [Figo (F)], and yellow [Sun Club (Y)] cultivars were analyzed by real-time quantitative polymerase chain reaction (PCR). Transcriptomic analysis identified 25,165 differentially expressed genes. The transcription abundance and expression level of genes annotated as anthocyanidin reductase (ANR1, ANR2), basic-helix-loop-helix (bHLH1), and glutathione S-transferases (GST1) were significantly upregulated in B, and the expression of anthocyanidin synthase (ANS) was highest in B except for N. However, chalcone isomerase (CHI2) and dihydroflavonol 4-reductase (DFR1, DFR2) were expressed at significantly lower levels in P, W, and Y. Correlation analysis revealed that bHLH1 might act as a positive regulator of ANS expression, promoting anthocyanin synthesis. Moreover, GST1-encoded proteins may be related to the accumulation and transport of both anthocyanin and procyanidin in the calla lily spathe. It is speculated that the formation of the black spathe is related to the accumulation of anthocyanins and procyanidins. However, the low expression of CHI2, DFR1, and DFR2 may result in the inhibition of anthocyanin synthesis, which may lead to lightening of the spathe color. This preliminary study revealed the mechanism responsible for calla lily spathe color, identifying the key genes involved, thus providing effective gene resources and a theoretical basis for flower color molecular breeding.
Cymbidium faberi, a member of the Cymbidium genus known for its fragrant blooms and graceful foliage, has recently become endangered in the wild due to reproductive challenges. This study aimed to establish systematically a tissue culture system for Cymbidium faberi Rolfe (wild species) by evaluating the effects of various plant growth regulators its propagation stages, including rhizome proliferation, differentiation, shoot strengthening, and rooting. The results showed that 0.5 mg·L−1 thidiazuron significantly promoted rhizome proliferation, achieving a proliferation coefficient of 6.08 after 60 days of culture. For adventitious bud induction, 1.92 mg·L−1 brassinolide was most effective, inducing 6.43 buds per rhizome with an average bud height of 5.25 mm after 90 days of culture. The optimal strategy for shoot growth was using 3.0 mg·L−1 1-naphthaleneacetic acid, resulting in an average shoot height of 6.47 cm after 60 days. The highest rooting rate of 87.5% was achieved with 0.5 mg·L−1 zeatin, producing an average of 3.5 roots per shoot with an average root length of 3.06 cm. This study successfully developed a propagation system for C. faberi and highlighted the significant role of BL in promoting rhizome differentiation. In conclusion, this study provides a robust propagation method to support the conservation and industrial development of C. faberi.
Arabidopsis thaliana Flowering locus T (FT) homologs have been shown to be sufficient to trigger flowering and to regulate flowering time in a wide range of plants. However, such a homologue for the perennial ornamental shrub tree peony has not yet been characterized. In this study, we isolated PsFT, which is a closely related FT homolog from reblooming [Paeonia ×lemoinei ‘High Noon’ (HN)] and nonreblooming [P. ×suffruticosa ‘Luo Yang Hong’ (LYH)] cultivars of tree peonies, and identified its potential role in the regulation of flowering time. The PsFT alleles from the two cultivars encode the same protein, which indicates that the polymorphisms observed in the coding region do not contribute to the distinct flowering phenotypes of HN and LYH. Comparative analyses of the PsFT expression patterns in HN and LYH indicated that PsFT might be associated with reblooming. Transgenic A. thaliana plants ectopically expressing PsFT exhibited a phenotype that included significantly early flowering compared with the wild-type (WT) plants. Taken together, our data provide valuable clues for shortening the juvenile periods and extending the flowering periods of perennial woody plants, such as tree peonies.
Coir is used around the world as a cultivation medium for plants; its commercial popularity is the result of its availability, low cost, and environmentally friendly characteristics. It is used as a medium in the hydroponic cultivation of Anthurium (Anthurium andraeanum Lind.) in Taiwan and is a new source for cut flower production around the world. Little is known about the nutrient requirements of Anthurium cultivated in coir under fluctuating climatic conditions. The objective of this study was to evaluate the influences of various nitrogen (N) concentrations on the growth and nutrient uptake of Anthurium cultivated in coir under different seasonal conditions. Four levels of N concentration in nutrient solution were used: 79 mg·L−1 (NS79 treatment), 105 mg·L−1 (NS105 treatment), 158 mg·L−1 (NS158 treatment), and 210 mg·L−1 (NS210 treatment) with NS105 serving as the control. The effects of N concentration and seasonal fluctuations on Anthurium were measured in dry weight, leaf growth, flower growth, and nutrient uptake at different growth stages during the 2-year study period. The results show that the dry weight, leaf area, and flower number were higher in plants receiving NS105 and NS158 treatments than those receiving NS79 and NS210 treatments. However, the NS158-treated plants produced better quality cut flowers than the NS105-treated plants in the first year of cultivation as indicated by their wider, circular spathe. Retarded growth of NS79-treated Anthurium was the product of insufficient N supply and reduced carbon (C) assimilation. The excess supply of N in the NS210 treatment resulted in small potassium (K) and magnesium (Mg) uptakes, which in turn resulted in poor growth in the second year of cultivation. However, the nutrient supplies in the NS158 and NS210 treatments yielded better Anthurium growth during the initial stage than the NS79- or NS105-treated groups. Regardless of plant growth, flower yield, and nutrient uptake, there were significant interactions between N treatments and seasonal fluctuations in subtropical conditions during year-round cultivation. We concluded that the limiting factor in Anthurium growth and yield during the spring and summer is the N supply, whereas climate conditions are the limiting factor during the fall and winter.
Leaf color mutants play an important role in our understanding of chlorophyll biosynthesis and catabolism. In this study, we obtained a yellow-green leaf mutant hy in an ethyl methanesulfonate mutagenized population of chinese cabbage (Brassica rapa ssp. pekinensis). The hy phenotype was controlled by a recessive allele at a single locus. The intrinsic photochemical activity of photosystem II (PSII) is impaired in hy, suggesting that absorbed light energy is not efficiently transferred from the light-harvesting complexes antenna to the PSII reaction centers and dissipated as heat or fluorescence. We measured chlorophyll content and chlorophyll precursors and analyzed the expression of key genes in the chlorophyll synthetic pathway in hy and wild type. The mutation phenotype was consistent with inhibited expression of chlorophyll a oxygenase (CAO) gene in the chlorophyll synthetic pathway. In mutant hy, CAO cDNA was cloned so that a C to T mutation at 1099 bp caused a conserved proline (Pro) to serine (Ser) mutation at the 367th amino acid in C-domain, which changed the secondary structure of CAO protein. We speculate that the mutation amino acid changed in the C-domain may affect the catalytic function in mutant CAO.
Based on the International Camellia Register (ICR), an analysis of 1616 cultivars of Sasanqua that were registered in 2022 and earlier was conducted. This analysis focused on the resource and biological characteristics of the cultivars. Additionally, a trait diversity analysis, principal component analysis, and cluster analysis of 118 cultivars that had complete morphological records were performed. The findings revealed a rich diversity of Sasanqua cultivars, with Japan, the United States, and Australia being the main sources. The primary flower color was red, followed by multiple colors, white, and rare colors. The predominant flower forms were single-petal and semi-double-petal, with a limited number of formal double-petal forms. Elliptical leaf shapes were the most common, and the predominant leaf colors were green and deep green. The flowering period mainly corresponded to early flowering cultivars. The phenotypic diversity index (H) of the 118 cultivars ranged from 0.31 to 1.84. The flower diameter exhibited the highest H value (1.84), whereas leaf shape had the lowest H value (0.31). The coefficient of variation (CV) ranged from 21.67% to 71.81%, with the flower diameter having the smallest CV (21.67%) and petal number having the largest CV (71.81%). The first three principal components, which accounted for a cumulative contribution rate of 62.49%, effectively represented most of the information regarding the seven trait indicators of the different cultivars. Furthermore, a cluster analysis was conducted based on the flower form, diameter, petal numbers, and other characteristics of the various cultivars. The 118 cultivars were divided into three groups. The first group could be used for breeding single-petal flower cultivars, whereas the third group exhibited a larger number of petals and could be used for breeding double-petal flower cultivars.
Turfgrass varietal identification is critical and allows turfgrass professionals to manage the turf based on the cultural requirements of the variety. On the Oklahoma State University (OSU) Baseball Field (OSUBF) in Stillwater, OK, some bermudagrass (Cynodon sp.) plants exhibited desirable traits but their exact identities were unknown due to the installation of multiple varieties over time. Accordingly, the major objective of this study was to identify if the desirable bermudagrass plants were from commercially available known varieties. Recently, the OSU turf bermudagrass breeding program developed and entered three fairway-type clonal bermudagrasses in the 2013 National Turfgrass Evaluation Program (NTEP) bermudagrass trial: OKC 1131, OKC 1163, and OKC 1302. The secondary objective was to create molecular marker profiles for these three experimental lines. Five OSUBF samples were analyzed using simple sequence repeat (SSR) markers, along with 24 clonal, commercially available turf bermudagrass varieties widely used in Oklahoma, the three OSU experimental clones, six randomly selected single plants from ‘Riviera’, and two controls for common bermudagrass (Cynodon dactylon) and african bermudagrass (Cynodon transvaalensis). SSR marker genotyping data indicated that the five OSUBF plants were clones of an identical bermudagrass. The OSUBF bermudagrass had the same fingerprint as ‘Astro-DLM’ bermudagrass for 14 out of 16 SSRs genotyped. Fifteen out of 30 additional SSR markers also showed differences between the OSUBF bermudagrass and ‘Astro-DLM’. The three OSU experimental clones were different from each other and had different fingerprints from the other tested varieties based on SSR profiles, indicating they are new breeding lines. These four distinct lines have potential to be released as new varieties if they demonstrate superior turf quality traits and adaptation over time.
Red leaf lettuce (Lactuca sativa) has high nutritional value and is frequently used in salads. In a plant factory with full electric lighting, if the spectrum is incorrect, then red leaf lettuce will have incomplete coloration. This study aimed to establish a light recipe for the mass production of red leaf lettuce using electric light sources in a plant factory by using indicators for quantitative assessment, including energy yield (EY) [grams of fresh weight (FW) harvested per kilowatt hour of electricity input for lighting], photon yield (PY) (grams of FW harvested per mole of photons delivered), anthocyanin yield per kilowatt hour (EYA), and anthocyanin yield per photon (PYA). First, the effects of four types of light quality on FW and anthocyanin content were examined. Then, two types of light quality, light-emitting diode with a red-to-blue photon ratio of 80:20 (R80:B20) and R20:B80, were selected for an experiment involving five treatments. An optimum light recipe (SR5SB1) including R80:B20 treatment during the early stage of cultivation (weeks 1 through 5 after sowing) followed by R20:B80 treatment during the final stage (week 6) was proposed. The SR5SB1 treatment led to FW, EYA, and PYA of 87.8 g/plant, 1.63 mg/kWh, and 0.57 mg·mol–1, respectively. This treatment resulted in the highest EYA and PYA, with 159% and 256% more anthocyanin productivity, respectively, compared with cool white treatment (with FW, EYA, and PYA of 65.8 g/plant, 0.63 mg/kWh, and 0.16 mg·mol–1, respectively). The proposed SR5SB1 light recipe enabled cultivation of red leaf lettuce with a balanced yield and anthocyanin production.