Pigment Diversity in Leaves of Caladium × hortulanum Birdsey and Transcriptomic and Metabolic Comparisons between Red and White Leaves.

Leaf color is a key ornamental characteristic of cultivated caladium (Caladium × hortulanum Birdsey), a plant with diverse leaf colors. However, the genetic improvement of leaf color in cultivated caladium is hindered by the limited understanding of leaf color diversity and regulation. In this study, the chlorophyll and anthocyanin content of 137 germplasm resources were measured to explore the diversity and mechanism of leaf color formation in cultivated caladium. Association analysis of EST-SSR markers and pigment traits was performed, as well as metabolomics and transcriptomics analysis of a red leaf variety and its white leaf mutant. We found significant differences in chlorophyll and anthocyanin content among different color groups of cultivated caladium, and identified three, eight, three, and seven EST-SSR loci significantly associated with chlorophyll-a, chlorophyll-b, total chlorophyll and total anthocyanins content, respectively. The results further revealed that the white leaf mutation was caused by the down-regulation of various anthocyanins (such as cyanidin-3-O-rutinoside, quercetin-3-O-glucoside, and others). This change in concentration is likely due to the down-regulation of key genes (four PAL, four CHS, six CHI, eight F3H, one F3'H, one FLS, one LAR, four DFR, one ANS and two UFGT) involved in anthocyanin biosynthesis. Concurrently, the up-regulation of certain genes (one FLS and one LAR) that divert the anthocyanin precursors to other pathways was noted. Additionally, a significant change in the expression of numerous transcription factors (12 NAC, 12 bZIP, 23 ERF, 23 bHLH, 19 MYB_related, etc.) was observed. These results revealed the genetic and metabolic basis of leaf color diversity and change in cultivated caladium, and provided valuable information for molecular marker-assisted selection and breeding of leaf color in this ornamental plant.

Comparative Plastomes of Curcuma alismatifolia (Zingiberaceae) Reveal Diversified Patterns among 56 Different Cut-Flower Cultivars.

Curcuma alismatifolia (Zingiberaceae) is an ornamental species with high economic value due to its recent rise in popularity among floriculturists. Cultivars within this species have mixed genetic backgrounds from multiple hybridization events and can be difficult to distinguish via morphological and histological methods alone. Given the need to improve identification resources, we carried out the first systematic study using plastomic data wherein genomic evolution and phylogenetic relationships from 56 accessions of C. alismatifolia were analyzed. The newly assembled plastomes were highly conserved and ranged from 162,139 bp to 164,111 bp, including 79 genes that code for proteins, 30 tRNA genes, and 4 rRNA genes. The A/T motif was the most common of SSRs in the assembled genomes. The Ka/Ks values of most genes were less than 1, and only two genes had Ka/Ks values above 1, which were rps15 (1.15), and ndhl (1.13) with petA equal to 1. The sequence divergence between different varieties of C. alismatifolia was large, and the percentage of variation in coding regions was lower than that in the non-coding regions. Such data will improve cultivar identification, marker assisted breeding, and preservation of germplasm resources.

Cross-Compatibility in Interspecific Hybridization of Different Curcuma Accessions.

Curcuma is extensively cultivated as a medicinal and ornamental plant in tropical and subtropical regions. Due to the bright bract color, distinctive inflorescence and long blooming period, it has become a new favorite in terms of the urban landscape, potted flowers and cut flowers. However, little research on breeding new cultivars using traditional plant breeding methods is available on the genus Curcuma. In the present study, pollen viability and stigma receptivity evaluation were performed, and the genetic relationship of 38 Curcuma accessions was evaluated, then 5 C. alismatifolia Gagnep. (Ca), 2 C. hybrid (Ch), 2 C. sparganiifolia Gagnep. cultivars and 4 Curcuma native species were selected as parents for subsequent interspecific cross-breeding. A total of 132 reciprocal crosses were carried out for interspecific hybridization, including 70 obverse and 62 inverse crosses. Obvious discrepancies among fruit-setting rates were manifested in different combinations and in reciprocal crosses. Results showed that the highest fruit-setting rate (87.5%) was observed in the Ca combinations. There were 87 combinations with a fruit-setting rate of 0%, which meant nearly 65.9% was incompatible. We concluded that C. alismatifolia 'Siam Shadow' (Ch34) was suitable as a male parent and C. petiolata Roxb. (Cpet) was suitable as a female parent to improve the fruit-setting rates. The maximum number of seeds per fruit (45.4) was obtained when C. alismatifolia 'Chiang Mai Pink' (Ca01) was used as a female parent followed by C. attenuata Wall. ex Baker (Catt) (42.8) and C. alismatifolia 'Splash' (Ca63) (39.6) as male parents. The highest germination rate was observed for the Ca group followed by Catt and C. sparganiifolia 'Maetang Sunrise' (Csms). The germination rates of Ca accessions ranged from 58.2% (C. alismatifolia 'Siam Scarlet' (Ca06) as a male parent) to 89.3% (C. alismatifolia 'Sitone' (Ca10) as a male parent) with an average value of 74.0%. Based on the results of hybrid identification, all the individuals from the four combinations exhibited paternal-specific bands, indicating that the true hybrid rates of crossings were 100%. Our results would facilitate the interspecific hybridization and introduction of genetic variation from wild species into the cultivars in Curcuma in the future, which could be helpful in realizing the sustainable application in urban green areas.

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.

Is simply washing hands before dialysis procedures sufficient for reducing peritoneal dialysis peritonitis?-A single center study from 2015 to 2020 in Yiwu, China.

INTRODUCTION: The study aimed to improve the qualified rate of hand hygiene and reduce the incidence of peritonitis in peritoneal dialysis (PD) patients. METHODS: A hand hygiene questionnaire was distributed to patients during home visits and outpatient visits in 2015 and 2020. Hand-washing practices were evaluated by collecting cultures from the hands of patients after hand washing, evaluating their household environment, and recording the antimicrobial resistance of pathogenic bacteria. RESULTS: Compared to patients in 2015, patients in 2020 had fewer errors in hand washing (p < 0.05), but the rate of qualification after hand washing was lower (p < 0.01). Furthermore, patients who used hand disinfectants after washing had a higher qualified rate. Coagulase-negative staphylococcus (CNS) was the most common isolated bacteria. From 2015 to 2020, the annual incidence of CNS PD peritonitis did not decrease, while the proportion of methicillin-resistant CNS decreased. CONCLUSION: The use of hand disinfectants after standard hand washing may help reduce the incidence of peritonitis in PD patients.

Complete Chloroplast Genome Sequences of Four Species in the Caladium Genus: Comparative and Phylogenetic Analyses.

Caladiums are promising colorful foliage plants due to their dazzling colors of the leaves, veins, stripes, and patches, which are often cultivated in pots or gardens as decorations. Four wild species, including C. bicolor, C. humboldtii, C. praetermissum, and C. lindenii, were employed in this study, where their chloroplast (cp) genomes were sequenced, assembled, and annotated via high-throughput sequencing. The whole cp genome size ranged from 162,776 bp to 168,888 bp, and the GC contents ranged from 35.09% to 35.91%. Compared with the single large copy (LSC) and single small copy (SSC) regions, more conserved sequences were identified in the inverted repeat regions (IR). We further analyzed the different region borders of nine species of Araceae and found the expansion or contraction of IR/SSC regions might account for the cp genome size variation. Totally, 131 genes were annotated in the cp genomes, including 86 protein-coding genes (PCGs), 37 tRNAs, and eight rRNAs. The effective number of codons (ENC) values and neutrality plot analyses provided the foundation that the natural selection pressure could greatly affect the codon preference. The GC3 content was significantly lower than that of GC1 and GC2, and codons ending with A/U had higher usage preferences. Finally, we conducted phylogenetic relationship analysis based on the chloroplast genomes of twelve species of Araceae, in which C. bicolor and C. humboldtii were grouped together, and C. lindenii was furthest from the other three Caladium species occupying a separate branch. These results will provide a basis for the identification, development, and utilization of Caladium germplasm.

The genomic and bulked segregant analysis of Curcuma alismatifolia revealed its diverse bract pigmentation.

Compared with most flowers where the showy part comprises specialized leaves (petals) directly subtending the reproductive structures, most Zingiberaceae species produce showy "flowers" through modifications of leaves (bracts) subtending the true flowers throughout an inflorescence. Curcuma alismatifolia, belonging to the Zingiberaceae family, a plant species originating from Southeast Asia, has become increasingly popular in the flower market worldwide because of its varied and esthetically pleasing bracts produced in different cultivars. Here, we present the chromosome-scale genome assembly of C. alismatifolia "Chiang Mai Pink" and explore the underlying mechanisms of bract pigmentation. Comparative genomic analysis revealed C. alismatifolia contains a residual signal of whole-genome duplication. Duplicated genes, including pigment-related genes, exhibit functional and structural differentiation resulting in diverse bract colors among C. alismatifolia cultivars. In addition, we identified the key genes that produce different colored bracts in C. alismatifolia, such as F3'5'H, DFR, ANS and several transcription factors for anthocyanin synthesis, as well as chlH and CAO in the chlorophyll synthesis pathway by conducting transcriptomic analysis, bulked segregant analysis using both DNA and RNA data, and population genomic analysis. This work provides data for understanding the mechanism of bract pigmentation and will accelerate breeding in developing novel cultivars with richly colored bracts in C. alismatifolia and related species. It is also important to understand the variation in the evolution of the Zingiberaceae family. Supplementary Information: The online version contains supplementary material available at 10.1007/s42994-022-00081-6.

A complete mitochondrial genome for fragrant Chinese rosewood (Dalbergia odorifera, Fabaceae) with comparative analyses of genome structure and intergenomic sequence transfers.

BACKGROUND: Dalbergia odorifera is an economically and culturally important species in the Fabaceae because of the high-quality lumber and traditional Chinese medicines made from this plant, however, overexploitation has increased the scarcity of D. odorifera. Given the rarity and the multiple uses of this species, it is important to expand the genomic resources for utilizing in applications such as tracking illegal logging, determining effective population size of wild stands, delineating pedigrees in marker assisted breeding programs, and resolving gene networks in functional genomics studies. Even the nuclear and chloroplast genomes have been published for D. odorifera, the complete mitochondrial genome has not been assembled or assessed for sequence transfer to other genomic compartments until now. Such work is essential in understanding structural and functional genome evolution in a lineage (Fabaceae) with frequent intergenomic sequence transfers. RESULTS: We integrated Illumina short-reads and PacBio CLR long-reads to assemble and annotate the complete mitochondrial genome of D. odorifera. The mitochondrial genome was organized as a single circular structure of 435 Kb in length containing 33 protein coding genes, 4 rRNA and 17 tRNA genes. Nearly 4.0% (17,386 bp) of the genome was annotated as repetitive DNA. From the sequence transfer analysis, it was found that 114 Kb of DNA originating from the mitochondrial genome has been transferred to the nuclear genome, with most of the transfer events having taken place relatively recently. The high frequency of sequence transfers from the mitochondria to the nuclear genome was similar to that of sequence transfer from the chloroplast to the nuclear genome. CONCLUSION: For the first-time, the complete mitochondrial genome of D. odorifera was assembled in this study, which will provide a baseline resource in understanding genomic evolution in the highly specious Fabaceae. In particular, the assessment of intergenomic sequence transfer suggests that transfers have been common and recent indicating a possible role in environmental adaptation as has been found in other lineages. The high turnover rate of genomic colinearly and large differences in mitochondrial genome size found in the comparative analyses herein providing evidence for the rapid evolution of mitochondrial genome structure compared to chloroplasts in Faboideae. While phylogenetic analyses using functional genes indicate that mitochondrial genes are very slowly evolving compared to chloroplast genes.

Complete chloroplast genomes of Zingiber montanum and Zingiber zerumbet: Genome structure, comparative and phylogenetic analyses.

Zingiber montanum (Z. montanum) and Zingiber zerumbet (Z. zerumbet) are important medicinal and ornamental herbs in the genus Zingiber and family Zingiberaceae. Chloroplast-derived markers are useful for species identification and phylogenetic studies, but further development is warranted for these two Zingiber species. In this study, we report the complete chloroplast genomes of Z. montanum and Z. zerumbet, which had lengths of 164,464 bp and 163,589 bp, respectively. These genomes had typical quadripartite structures with a large single copy (LSC, 87,856-89,161 bp), a small single copy (SSC, 15,803-15,642 bp), and a pair of inverted repeats (IRa and IRb, 29,393-30,449 bp). We identified 111 unique genes in each chloroplast genome, including 79 protein-coding genes, 28 tRNAs and 4 rRNA genes. We analyzed the molecular structures, gene information, amino acid frequencies, codon usage patterns, RNA editing sites, simple sequence repeats (SSRs) and long repeats from the two chloroplast genomes. A comparison of the Z. montanum and Z. zerumbet chloroplast genomes detected 489 single-nucleotide polymorphisms (SNPs) and 172 insertions/deletions (indels). Thirteen highly divergent regions, including ycf1, rps19, rps18-rpl20, accD-psaI, psaC-ndhE, psbA-trnK-UUU, trnfM-CAU-rps14, trnE-UUC-trnT-UGU, ccsA-ndhD, psbC-trnS-UGA, start-psbA, petA-psbJ, and rbcL-accD, were identified and might be useful for future species identification and phylogeny in the genus Zingiber. Positive selection was observed for ATP synthase (atpA and atpB), RNA polymerase (rpoA), small subunit ribosomal protein (rps3) and other protein-coding genes (accD, clpP, ycf1, and ycf2) based on the Ka/Ks ratios. Additionally, chloroplast SNP-based phylogeny analyses found that Zingiber was a monophyletic sister branch to Kaempferia and that chloroplast SNPs could be used to identify Zingiber species. The genome resources in our study provide valuable information for the identification and phylogenetic analysis of the genus Zingiber and family Zingiberaceae.

Complete Chloroplast Genomes of Three Medicinal Alpinia Species: Genome Organization, Comparative Analyses and Phylogenetic Relationships in Family Zingiberaceae.

Alpinia katsumadai (A. katsumadai), Alpinia oxyphylla (A. oxyphylla) and Alpinia pumila (A. pumila), which belong to the family Zingiberaceae, exhibit multiple medicinal properties. The chloroplast genome of a non-model plant provides valuable information for species identification and phylogenetic analysis. Here, we sequenced three complete chloroplast genomes of A. katsumadai, A. oxyphylla sampled from Guangdong and A. pumila, and analyzed the published chloroplast genomes of Alpinia zerumbet (A. zerumbet) and A. oxyphylla sampled from Hainan to retrieve useful chloroplast molecular resources for Alpinia. The five Alpinia chloroplast genomes possessed typical quadripartite structures comprising of a large single copy (LSC, 87,248-87,667 bp), a small single copy (SSC, 15,306-18,295 bp) and a pair of inverted repeats (IR, 26,917-29,707 bp). They had similar gene contents, gene orders and GC contents, but were slightly different in the numbers of small sequence repeats (SSRs) and long repeats. Interestingly, fifteen highly divergent regions (rpl36, ycf1, rps15, rpl22, infA, psbT-psbN, accD-psaI, petD-rpoA, psaC-ndhE, ccsA-ndhD, ndhF-rpl32, rps11-rpl36, infA-rps8, psbC-psbZ, and rpl32-ccsA), which could be suitable for species identification and phylogenetic studies, were detected in the Alpinia chloroplast genomes. Comparative analyses among the five chloroplast genomes indicated that 1891 mutational events, including 304 single nucleotide polymorphisms (SNPs) and 118 insertion/deletions (indels) between A. pumila and A. katsumadai, 367 SNPs and 122 indels between A. pumila and A. oxyphylla sampled from Guangdong, 331 SNPs and 115 indels between A. pumila and A. zerumbet, 371 SNPs and 120 indels between A. pumila and A. oxyphylla sampled from Hainan, and 20 SNPs and 23 indels between the two accessions of A. oxyphylla, were accurately located. Additionally, phylogenetic relationships based on SNP matrix among 28 whole chloroplast genomes showed that Alpinia was a sister branch to Amomum in the family Zingiberaceae, and that the five Alpinia accessions were divided into three groups, one including A. pumila, another including A. zerumbet and A. katsumadai, and the other including two accessions of A. oxyphylla. In conclusion, the complete chloroplast genomes of the three medicinal Alpinia species in this study provided valuable genomic resources for further phylogeny and species identification in the family Zingiberaceae.

Transcriptome analysis of the genes regulating phytohormone and cellular patterning in Lagerstroemia plant architecture.

Plant architecture is a popular research topic because plants with different growth habits that may generate economic or ornamental value are in great demand by orchards and nurseries. However, the molecular basis of the architecture of woody perennial plants is poorly understood due to the complexity of the phenotypic and regulatory relationships. Here, transcriptional profiling of dwarf and non-dwarf crapemyrtles was performed, and potential target genes were identified based on the phenotype, histology and phytohormone metabolite levels. An integrated analysis demonstrated that the internode length was explained mainly by cell number and secondarily by cell length and revealed important hormones in regulatory pathway of Lagerstroemia architecture. Differentially expressed genes (DEGs) involved in phytohormone pathways and cellular patterning regulation were analysed, and the regulatory relationships between these parameters were evaluated at the transcriptional level. Exogenous indole-3-acetic acid (IAA) and gibberellin A4 (GA4) treatments further indicated the pivotal role of auxin in cell division within the shoot apical meristem (SAM) and suggested an interaction between auxin and GA4 in regulating the internode length of Lagerstroemia. These results provide insights for further functional genomic studies on the regulatory mechanisms underlying Lagerstroemia plant architecture and may improve the efficiency of woody plant molecular breeding.

Research on Handwashing Techniques of Peritoneal Dialysis Patients From Yiwu, Southeast China.

The aim of the present study was to evaluate handwashing technique, bacteriology, and factors influencing handwashing technique of 86 stable chronic peritoneal dialysis (PD) patients from Yiwu City in Southeast China. Based on the "Hygienic standard for disinfection in the hospital", we also performed sampling for bacteriology from PD operators after they washed their hands. We compared their clinical features including the pathogenic bacteria of their previous peritonitis episodes and their handwashing evaluation results according to their bacteriologic sampling results. 65% of patients turned off the tap by bare hand, and 74% did not follow the six-step handwashing method. Dialysis duration longer than 6 months (P = 0.04) and lower income (P = 0.05) were independent risk factors for higher handwashing error scores. The overall rate of appropriate handwashing, according to the "hygienic standard for disinfection in the hospital" was 26%. The bacteriologic sampling results showed that the most common pathogenic bacterium was Staphylococcus aureus (92%). PD operators whose hand bacteria culture was qualified contained a lower proportion of participants with advanced age (P = 0.07). Patients with repeated peritonitis occurrence had a significantly higher score on handwashing error (P < 0.01) and were more likely to develop Staphylococcus infection. We found that in Yiwu city patients on dialysis for more than 6 months, were of low income and had multiple prior episodes of PD peritonitis had poor handwashing compliance. Elderly patients had higher rates of positive bacterial culture (Staphylococcus) from their hands.

Identification and Validation of SNP Markers Linked to Dwarf Traits Using SLAF-Seq Technology in Lagerstroemia.

The genetic control of plant architecture is a promising approach to breed desirable cultivars, particularly in ornamental flowers. In this study, the F1 population (142 seedlings) derived from Lagerstroemia fauriei (non-dwarf) × L. indica 'Pocomoke' (dwarf) was phenotyped for six traits (plant height (PH), internode length (IL), internode number, primary lateral branch height (PLBH), secondary lateral branch height and primary branch number), and the IL and PLBH traits were positively correlated with the PH trait and considered representative indexes of PH. Fifty non-dwarf and dwarf seedlings were pooled and subjected to a specific-locus amplified fragment sequencing (SLAF-seq) method, which screened 1221 polymorphic markers. A total of 3 markers segregating between bulks were validated in the F1 population, with the M16337 and M38412 markers highly correlated with the IL trait and the M25207 marker highly correlated with the PLBH trait. These markers provide a predictability of approximately 80% using a single marker (M25207) and a predictability of 90% using marker combinations (M16337 + M25207) in the F1 population, which revealed that the IL and the PLBH traits, especially the PLBH, were the decisive elements for PH in terms of molecular regulation. Further validation was performed in the BC1 population and a set of 28 Lagerstroemia stocks using allele-specific PCR (AS-PCR) technology, and the results showed the stability and reliability of the SNP markers and the co-determination of PH by multiple genes. Our findings provide an important theoretical and practical basis for the early prediction and indirect selection of PH using the IL and the PLBH, and the detected SNPs may be useful for marker-assisted selection (MAS) in crape myrtle.