Auxin and carbohydrate control flower bud development in Anthurium andraeanum during early stage of sexual reproduction.

BACKGROUND: Flower buds of Anthurium andraeanum frequently cease to grow and abort during the early flowering stage, resulting in prolonged planting times and increased commercialization costs. Nevertheless, limited knowledge exists of the mechanism of flower development after initiation in A. andraeanum. RESULTS: In this study, the measurement of carbohydrate flow and intensity between leaves and flowers during different growth stages showed that tender leaves are strong sinks and their concomitant flowers are weak ones. This suggested that the tender leaves compete with their concomitant flower buds for carbohydrates during the early growth stages, potentially causing the abortion of the flower buds. The analysis of transcriptomic differentially expressed genes suggested that genes related to sucrose metabolism and auxin response play an important role during flower bud development. Particularly, co-expression network analysis found that AaSPL12 is a hub gene engaged in flower development by collaborating carbohydrate and auxin signals. Yeast Two Hybrid assays revealed that AaSPL12 can interact with AaARP, a protein that serves as an indicator of dormancy. Additionally, the application of exogenous IAA and sucrose can suppress the expression of AaARP, augment the transcriptional abundance of AaSPL12, and consequently expedite flower development in Anthurium andraeanum. CONCLUSIONS: Collectively, our findings indicated that the combination of auxin and sugar signals could potentially suppress the repression of AaARP protein to AaSPL12, thus advancing the development of flower buds in Anthurium andraeanum.

Identification of key genes responsible for green and white colored spathes in Anthurium andraeanum (Hort.).

Modern anthuriums, Anthurium andraeanum (Hort.) are among the most popular flowering plants and widely used for interior decoration. Their popularity is largely attributed to the exotic spathes with different colors. Previous studies have reported color development in red spathe cultivars, but limited information is available on key genes regulating white and green colored spathes. This study analyzed anthocyanin, chlorophyll, and carotenoid contents as well as transcript differences in spathes of eight cultivars that differed in spathe colors ranging from red to white and green. Results showed that increased expression of a transcription factor AaMYB2 was associated with elevated levels of anthocyanin in spathes, but decreased expression of AaMYB2 and increased expression of AaLAR (leucoanthocyanidin reductase) and AaANR (anthocyanidin reductase) were accompanied with the accumulation of colorless proanthocyanidin, thus the white spathe. As to the green colored spathe, chlorophyll content in the green spathe cultivar was substantially higher than the other cultivars. Correspondingly, transcripts of chlorophyll biosynthesis-related genes AaHemB (porphobilinogen synthase) and AaPor (protochlorophyllide oxidoreductase) were highly upregulated but almost undetectable in white and red spathes. The increased expression of AaHemB and AaPor was correlated with the expression of transcription factor AaMYB124. Subsequently, qRT-PCR analysis confirmed their expression levels in nine additional cultivars with red, white, and green spathes. A working model for the formation of white and green spathes was proposed. White colored spathes are likely due to the decreased expression of AaMYB2 which results in increased expression of AaLAR and AaANR, and the green spathes are attributed to AaMYB124 enhanced expression of AaHemB and AaPor. Further research is warranted to test this working model.

The complete chloroplast genome sequence of Anthurium andraeanum Linden (Araceae; Pothoideae).

The chloroplast genome of Anthurium andraeanum Linden 1877 was assembled and analyzed in this study. The genome size is 162,560 bp, of which contains a large single-copy (LSC) region with 88,814 bp, a small single-copy (SSC) region with 22,856 bp, and two inverted repeat regions (IRA and IRB) with 25,445 bp, respectively. The plastome contains 124 genes, including 80 protein-coding genes, 37 tRNAs, six rRNAs and one pseudogene. Phylogenetic analysis indicated that A. andraeanum is a member of Pothoideae and sister to A. huixtlense.

Comparative Physiological and Transcriptome Analyses of Tolerant and Susceptible Cultivars Reveal the Molecular Mechanism of Cold Tolerance in Anthurium andraeanum.

Anthurium andraeanum is a tropical ornamental flower. The cost of Anthurium production is higher under low temperature (non-freezing) conditions; therefore, it is important to increase its cold tolerance. However, the molecular mechanisms underlying the response of Anthurium to cold stress remain elusive. In this study, comparative physiological and transcriptome sequencing analyses of two cultivars with contrasting cold tolerances were conducted to evaluate the cold stress response at the flowering stage. The activities of superoxide dismutase and peroxidase and the contents of proline, soluble sugar, and malondialdehyde increased under cold stress in the leaves of the cold tolerant cultivar Elegang (E) and cold susceptible cultivar Menghuang (MH), while the soluble protein content decreased in MH and increased in E. Using RNA sequencing, 24,695 differentially expressed genes (DEGs) were identified from comparisons between cultivars under the same conditions or between the treatment and control groups of a single cultivar, 9132 of which were common cold-responsive DEGs. Heat-shock proteins and pectinesterases were upregulated in E and downregulated in MH, indicating that these proteins are essential for Anthurium cold tolerance. Furthermore, four modules related to cold treatment were obtained by weighted gene co-expression network analysis. The expression of the top 20 hub genes in these modules was induced by cold stress in E or MH, suggesting they might be crucial contributors to cold tolerance. DEGs were significantly enriched in plant hormone signal transduction pathways, trehalose metabolism, and ribosomal proteins, suggesting these processes play important roles in Anthurium's cold stress response. This study provides a basis for elucidating the mechanism of cold tolerance in A. andraeanum and potential targets for molecular breeding.

Identification of microRNA158 from Anthurium andraeanum and Its Function in Cold Stress Tolerance.

Anthurium andraeanum is a tropical flower with high ornamental and economic value. Cold stress is one of the major abiotic stresses affecting the quality and value of A. andraeanum; thus, improving the cold tolerance of this species is an important breeding objective. MicroRNAs (miRNAs) have a critical role in plant abiotic stress responses, but their specific molecular regulatory mechanisms are largely unknown, including those related to the cold stress response in A. andraeanum. Here, we identified and cloned the precursor of miR158 from A. andraeanum (Aa-miR158). Both Aa-miR158 and its target gene (c48247) had higher expression levels in strong leaves than in other tissues or organs. Further study revealed that the transcript level of Aa-miR158 was increased by cold stress. Heterologous overexpression of Aa-miR158 improved cold stress tolerance in Arabidopsis, which was associated with decreases in the malondialdehyde (MDA) concentration and relative electrical conductivity (REC) as well as increases in peroxidase (POD) and catalase (CAT) activity. Moreover, overexpressing Aa-miR158 significantly increased the expression of endogenous genes related to cold stress tolerance and reactive oxygen species (ROS) levels in transgenic Arabidopsis under cold stress. Overall, our results demonstrate that Aa-miR158 is significantly involved in the cold stress response and provide a new strategy for cold tolerance breeding of A. andraeanum.

Somatic Embryogenesis of Anthurium andraeanum Linden., -A Tropical Florists' Plant.

The global floriculture market is expected to reach US$41.1 billion by 2027 at a CAGR of 5% over the analysis period 2020-2027; on the year 2020, the recorded market value in this trade was US$29.2 billion. The florists mainly use Anthurium andraeanum flowers in fashionable bouquets and floral arrangements because of their beautiful, attractive bright colored eye-catching spathe, candle-like spadix, prolonged vase life, etc. The cut flower industry always seeks elite cultivars and new hybrids of A. andraeanum, that in turn depend on the availability of large numbers of clonal planting propagules. In vitro somatic embryogenesis is an important technique for large-scale clonal propagation, development of transgenic plants, creation of new variety by somaclonal variation, mutagenesis on in vitro plants, and germplasm preservation for future use. Here, we describe the protocol of somatic embryogenesis of Anthurium andraeanum cv. Cancan, an important commercial cultivated variety. The protocol has been optimized by using 4 different types of culture media which are used during embryogenic callus induction, multiplication of callus, induction of somatic embryogenesis, and maturation plus conversion of embryos into plantlets. The protocol outlines the detailed methods from mother plant procurement to hardening of micro plants that is ready to transfer in the field and it can be used for large-scale commercial propagation.

Integrated small RNA profiling and degradome analysis of Anthurium andraeanum cultivars with different-colored spathes.

MicroRNAs (miRNAs) are known to play vital roles in coloration of leaves, flowers, and fruits in plants. However, their functions in spathe coloration are poorly known. Anthurium andraeanum is a popular ornamental plant with various spathe colors. In this study, small RNA and degradome libraries from three A. andraeanum cultivars with different-colored spathes were constructed and sequenced. Illumina sequencing resulted in 94 conserved miRNAs, and 34 novel miRNAs in total were then identified based on precursor sequences and hairpin structures. Differential expression analysis showed that 52, 51, and 49 miRNAs were differentially expressed in comparisons of orange- versus white-colored spathe, purple- versus white-colored spathe, and purple- versus orange-colored spathe, respectively. The expression patterns of miRNAs and their corresponding targets involved in spathe coloration were further analyzed, and displayed that miR156b and miR529 were highly abundant in the spathes with higher anthocyanin content. These two miRNAs co-targeted a gene encoding SPL17, which may function as a negative regulator in anthocyanin accumulation. In addition, miR408 was also abundantly expressed in purple- and orange-colored spathes, and its typical targets were also identified. This comprehensive integrated analysis provides insight into the miRNA-mediated genetic regulation in spathe coloration of A. andraeanum.

Profiling of Volatile Compounds and Associated Gene Expression in Two Anthurium Cultivars and Their F1 Hybrid Progenies.

Anthurium is an important ornamental crop in the world market and its floral scent can enhance its ornamental value. To date, studies of the components and formation mechanism of the floral scent of Anthurium are relatively few. In this study, the scent profiles of two Anthurium varieties were measured by gas chromatograph-mass spectrometer (GC-MS). There were 32 volatile organic compounds (VOCs) identified in Anthurium 'Mystral', and the most abundant compound was eucalyptol (57.5%). Extremely small amounts of VOCs were detected in Anthurium 'Alabama'. Compared with A. 'Alabama', most genes related to floral scent synthesis exhibited a higher expression in A.'Mystral', including AaDXS, AaDXR, AaMDS, AaHDS, AaTPS, AaDAHPS, AaADT2, AaPAL1, and AaPAL2. In order to produce new varieties of Anthurium with fragrance, 454 progenies of two crossbred combinations of A. 'Mystral' and A. 'Alabama' were obtained. Four F1 generation plants with different floral scent intensities were selected for further study. The major components of floral scent in the progenies were similar to that of the parental A.'Mystral' plant. The expression patterns of genes related to floral scent synthesis were consistent with the relative contents of different types of VOCs. This study revealed the profiles of volatile compounds and associated gene expression in two Anthurium cultivars and their F1 hybrids, which provided a basis for the floral scent inheritance of Anthurium andraeanum.

Bioreduction: the biological activity, characterization, and synthesis of silver.

Today, nanoparticles are effectively used in different areas. Initially, physical and chemical methods were used in the synthesis of nanoparticles. Biosynthesis (green synthesis) has emerged as an alternative to overcome the toxic effects of chemically synthesized nanoparticles. In this study, green synthesis of silver nanoparticles (AgNPs) with the leaf extract of Anthurium andraeanum was performed. UV-Vis spectrophotometry, scanning transmission electron microscopy, and XRD were applied to characterize the biosynthesized nanoparticles. As a result of the characterization, the spectra showed that a spectrum at a wavelength of about 419 nm and a spherical size of 38 nm nanoparticles was formed. Antibacterial and biofilm inhibition activities of AgNPs against gram-positive and gram-negative bacteria were determined. AgNPs at a concentration of 1 mg/mL showed antibacterial activity against all of the bacterial strains. In the antibiofilm activity study, the highest inhibition percentage was obtained against the P. fluorescens strain at 87.1%, at a concentration of 0.5 mg/mL.

The AabHLH35 Transcription Factor Identified from Anthurium andraeanum is Involved in Cold and Drought Tolerance.

Anthurium andraeanum Lind. is a popular potted and cut-flower plant with an attractive spathe and foliage. It is native to tropical rainforest areas and is able to blossom throughout the year under suitable conditions. However, various abiotic stresses seriously restrict the ornamental value of A. andraeanum and increase the costs of cultivation. A dark green (dg) leaf color mutant of A. andraeanum 'Sonate', which accumulates high levels of anthocyanin, has shown increased vigor and tolerance to stresses during cultivation and is, thus, an ideal germplasm for studying stress tolerance in this species. Here, we show that the anthocyanin content in dg mutant plants at different stages of leaf development was higher than in wild-type (WT) plants, and the ability to tolerate under low-temperature (LT, 14 °C) stress was stronger in dg than in WT plants. RNA-Seq of cDNA libraries from young leaves of dg and WT identified AabHLH35 as a differentially expressed gene (DEG) that was significantly up-regulated in dg. Furthermore, heterologous expression of AabHLH35 improved tolerance to cold and drought stresses in Arabidopsis. These results have built an important molecular foundation for further study of stress tolerance in A. andraeanum.

An Efficient Somatic Embryo Liquid Culture System for Potential Use in Large-Scale and Synchronic Production of Anthurium andraeanum Seedlings.

Anthurium andraeanum Lind. is the second most important tropical flower in the world flower market. Somatic embryogenesis and plant regeneration in Anthurium has been reported previously; however, a stable and effective method for its commercial use has not been available. In this study, an efficient somatic embryogenesis and liquid culture system for large-scale production of A. andraeanum seedlings was achieved. Building on previous research, this study investigated the main factors for proembryogenic mass (PEM) proliferation, somatic embryo (SE) development, and SE germination in Anthurium. The results showed that relatively low concentrations of plant growth regulators, mineral nutrition, and sucrose promoted PEM proliferation, SE formation, and germination in a liquid culture system. This system can be described as follows: PEMs were induced from leaf blade explants on Murashige & Skoog (MS) medium with half-strength MS macronutrients (1/2 MS) containing 2.0 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D), 0.5 mg L-1 kinetin (KT), and 3% sucrose and were proliferated in ½ MS liquid medium containing 1.0 mg L-1 2,4-D, 0.5 mg L-1 KT, and 3% sucrose. The highest proliferation coefficients were 5.11-5.16. PEMs were then transferred to MS medium with 1/8 MS macronutrients (1/8 MS) liquid medium containing 1% sucrose to develop into globular embryos and mature embryos. Finally, the mature embryos were placed on four layers of absorbent filter paper saturated with 1/8 MS liquid medium containing 1% sucrose for germination, and an average of 60 seedlings per gram SEs was obtained. This liquid culture system can be used in large-scale and synchronic production of Anthurium seedlings.

Growth promotion and disease resistance induced in Anthurium colonized by the beneficial root endophyte Piriformospora indica.

BACKGROUND: Anthurium andraeanum, an important ornamental flower, has to go through a growth-delaying period after transfer from tissue culture to soil, which requires time and extra costs. Furthermore, during this period, the plantlets are highly susceptible to bacterial infections, which results in impaired development and severe losses. Here, we aimed to address whether application of the endophytic fungus, Piriformospora indica protects the A. andraeanum root system during the critical propagation period, and whether P. indica reduce the mortality rate by stimulating the host's resistance against diseases. RESULTS: We demonstrate that P. indica shortens the recovery period of Anthurium, promotes growth and confers disease resistance. The beneficial effect of P. indica results in faster elongation of Anthurium roots early in the interaction. P. indica-colonized plants absorb more phosphorus and exhibit higher photosynthesis rates than uncolonized control plants. Moreover, higher activities of stress-related enzymes, of jasmonic acid levels and mRNA levels of jasmonic acid-responsive genes suggest that the fungus prepares the plant to respond more efficiently to potentially upcoming threats, including bacterial wilt. CONCLUSION: These results suggest that P. indica is a helpful symbiont for promoting Anthurium rooting and development. All our evidences are sufficient to support the disease resistance conferred by P. indica through the plant-fungal symbiosis. Furthermore, it implicates that P. indica has strong potential as bio-fertilizer for utilization in ornamental plant cultivation.

Pathotypes of Xanthomonas axonopodis pv. dieffenbachiae Isolated from Anthurium andraeanum in China.

Anthurium blight, caused by Xanthomonas axonopodis pv. dieffenbachiae (Xad), is one of the most serious diseases of Anthurium andraeanum. However, little is known about variations in virulence between Xad pathotypes. Here, we examined the virulence of 68 Xad strains isolated from 30 anthurium plants from five regions of China against five different anthurium cultivars. Seven bacterial pathotypes were identified based on disease index and incidence analyses following foliar spray or leaf-clip inoculation. The resulting disease susceptibility patterns for pathotypes I⁻VII were RRRSS, RRSRS, RSRSR, RRSSS, RSSRS, RSSSS, and SSSSS, respectively. Overall, 72% of tested strains belonged to pathotypes VI or VII and were highly virulent. A further 22.1% of strains showed medium-level virulence and were classed as pathotype III, IV, or V, while the remaining 5.9% of strains were pathotype I or II, showing low virulence. Further analysis revealed differences in the virulence of Xad strains from the same anthurium cultivar, with variation also observed in pathovars associated with the same cultivar from different areas. Our results reveal the diversity and complexity of the Xad population structure in China and suggest that investigation of Xad pathotypes provides useful information to guide the identification and use of resistant varieties of A. andraeanum.

Comparative profiling of microRNAs and their effects on abiotic stress in wild-type and dark green leaf color mutant plants of Anthurium andraeanum 'Sonate'.

MicroRNAs (miRNAs) are a class of non-coding small RNAs that play important roles in the regulation of gene expression. Although plant miRNAs have been extensively studied in model systems, less is known in other plants with limited genome sequence data, including Anthurium andraeanum. To identify miRNAs and their target genes in A. andraeanum and study their responses to abiotic stresses, we conducted deep-sequencing of two small RNA (sRNA) libraries prepared from young leaves of wild-type (WT) and dark green (dg) leaf color mutant plants of A. andraeanum 'Sonate'. A total of 53 novel miRNAs were identified, 32 of which have been annotated to 18 miRNA families. 10 putative miRNAs were found to be differentially expressed in WT and dg, among which two miRNAs were significantly up-regulated and eight down-regulated in dg relative to WT. One differentially expressed miRNA, Aa-miR408, was dramatically up-regulated in dg. qRT-PCR analysis and heterologous expression of Aa-miR408 in Arabidopsis under different stress treatments suggest that Aa-miR408 is involved in abiotic stress responses in A. andraeanum. Our results provide a foundation for further dissecting the roles of miRNAs and their targets in regulating abiotic stress tolerance in A. andraeanum.

Influence of light intensity on chloroplast development and pigment accumulation in the wild-type and etiolated mutant plants of Anthurium andraeanum 'Sonate'.

Seedlings of wild-type and etiolate mutant plants of Anthurium andraeanum cultivar 'Sonate' were treated for 15 d with different light intensities (20, 100, and 400 µmol·m-2·s-1) to analyze leaf plastid development and pigment content. Significant changes appeared in treated seedlings, including in leaf color, plastid ultrastructure, chloroplast development gene AaGLK expression, chlorophyll and anthocyanin contents, and protoplast shape. Wild-type and etiolated plants exhibited different plastid structures under the same light condition. The results suggest that light intensity is a crucial environmental factor influencing plastid development and leaf color formation in the A. andraeanum cultivar 'Sonate'.

In silico identification of alternative oxidase 2 (AOX2) in monocots: A new evolutionary scenario.

We identified AOX2 genes in monocot species from Lemnoideae (Spirodela polyrhiza, Lemna gibba and Landoltia punctata), Pothoideae (Anthurium andraeanum and Anthurium amnicola) and Monsteroideae (Epipremnum aureum) subfamilies within the Araceae, an early-diverging monocot family. These findings highlight the presence of AOX2 in the most ancient monocot ancestor and also that at least partial loss of this gene occurred during speciation events within several monocot orders. The presence of AOX2 in monocot species challenges (1) new understanding of the evolutionary history of the AOX gene family in angiosperms and (2) drives experimental and bioinformatics efforts to explore functional relevance of the two AOX gene family members for plant growth and development. Knowledge gain in this field will impact running strategies on AOX-derived functional marker candidate development for plant breeding.

[Effects of CO2 fertilization on photosynthesis and growth of cut Anthurium andraeanum in solar greenhouse in winter]. / æ—¥å ‰æ¸©å®¤å†¬å­£å¢žæ–½CO2å¯¹åˆ‡èŠ±çº¢æŽŒå ‰åˆä½œç”¨åŠç”Ÿé•¿å‘è‚²çš„å½±å“.

Aiming at the problem of the acute shortage of CO2 in winter production of cut Anthurium andraeanum in solar greenhouse, the effect of CO2 fertilization on photosynthetic characteristics and growth performance of A. andraeanum 'Fire' was investigated. Three treatments with different concentrations of CO2 were designed, i.e., 700, 1000 and 1300 Μmol·mol-1, with receiving no extra CO2 as the control. The results showed that for the CO2-fertilized plants, the photosynthetic rate, intercellular CO2 concentration and water use efficiency were significantly greater than those in the control plants after CO2 fertilization for 60 days, and the largest increase range was observed in the 1000 Μmol·mol-1 CO2 treatment, whereas the stomata conductance was significantly reduced compared with the control. Meanwhile, the contents of soluble sugar, starch and soluble protein in CO2-fertilized plants were significantly higher than those in control plants. Moreover, the quality of cut flowers with CO2 fertilization was remarkably superior to control flowers in term of the parameters including spathe size, spathe color, peduncle length, leaf growth performance and peduncle growth rate. The most superior improvement was observed in the 1000 Μmol·mol-1 CO2 treatment. It was therefore concluded that CO2 fertilization of 1000 Μmol·mol-1 could effectively improve the winter production of cut A. andraeanum in solar greenhouse.

Growth and yield of anthurium in response to sawdust mulching / Crescimento e produção de antúrio em resposta a cobertura do solo com serragem de madeira

ABSTRACT: The objectives of the study were to analyze the effect of sawdust mulch on the: (1) soil characteristics; (2) growth and flower yield of the anthurium cv. 'Apalai'. Assay was conducted in a totally randomized design in subdivided plots, with five treatments and eight replications. The treatment consisted of five volumes of sawdust 0, 20, 40, 60 and 80L m-2, distributed over the bed, every three months. Soil, plants and flower stalks were evaluated during two years. Soil temperature, moisture, organic matter, bulk density and water retention conditions were improved, while the leaf area of plants and the yield of flower stalks were increased when the soil were mulched with sawdust. In addition to increasing soil organic matter, however, no change occurred in the level of nutrients in plants. Sawdust also improved the dimension of flower stalks. Application of 40L m-2 of sawdust every three months is recommended.

RESUMO: Objetivou-se analisar o efeito da serragem de madeira: (1) nas características do solo; (2) no crescimento e produção de hastes florais de anthurium cv. 'Apalai'. O ensaio foi conduzido em delineamento inteiramente casualizado em parcelas subdivididas, com cinco tratamentos e oito repetições. Os tratamentos consistiram em cinco volumes de serragem 0, 20, 40, 60 e 80L m-2, distribuídos sobre os canteiros, a cada três meses. O solo, as plantas e hastes florais foram avaliados por dois anos. A temperatura, a umidade, o teor de matéria orgânica, a densidade e a retenção de água do solo melhoraram, enquanto a área foliar e a produção de hastes florais aumentaram quando o solo foi coberto com serragem. Apesar do aumento do teor de matéria orgânica, não ocorreram modificações no teor de nutrientes nas plantas. A serragem também melhorou as dimensões das hastes florais. Recomenda-se aplicação de 40L m-2 de serragem a cada três meses.

Nematoides fitoparasitos em áreas de cultivo de antúrio dos estados de São Paulo, Paraná e Santa Catarina / Plant parasitic nematodes in anthurium growing areas from São Paulo, Paraná and Santa Catarina States, Brazil

O objetivo do presente trabalho foi identificar os nematoides associados a plantas de antúrio (Anthurium andraeanum) cultivadas como flor de corte (13 amostras) ou plantas em vaso (41 amostras) nos estados de São Paulo, Paraná e Santa Catarina. Nematoides foram extraídos de 10g de raízes e 250cm3 de solo ou substrato e identificados sob microscópio de luz. A espécie mais frequente foi Radopholus similis, detectada em 54% das amostras de antúrio cultivado como flor de corte. Constituíram novas ocorrências em antúrio no Brasil: Helicotylenchus erythrinae, H. californicus, H. multicinctus, Meloidogyne paranaensis e R. similis. Entretanto, nenhum nematoide parasito de plantas foi encontrado nos antúrios cultivados em vaso, com substrato de fibra de coco. .

The aim of this research was to identify plant parasitic nematodes associated with Anthurium andraeanum plants cultivated as cut flowers (13 samples) or pot flowers (41 samples) in the States of São Paulo, Paraná and Santa Catarina, Brazil. Nematodes were extracted from 10g of roots and 250cm3 of soil by centrifugation method and identified under microscope. The most frequently occurring species was Radopholus similis detected on 54% of anthuriums cultivated as cut flowers. Among the identified species, the following associations constitute new records to Brazil in anthuriums: Helicotylenchus erythrinae, H. californicus, H. multicinctus, Meloidogyne paranaensis and R. similis. However, no plant parasitic nematodes were detected on A. andraeanum cultivated as pot flowers in coconut fiber substrate. .

Phenotype and transcriptome analysis reveals chloroplast development and pigment biosynthesis together influenced the leaf color formation in mutants of Anthurium andraeanum 'Sonate'.

Leaf color is one of the well-sought traits in breeding program for Anthurium andraeanum Lind. Knowledge of mechanisms in anthuriums to produce leaves with different shades of green would help to effectively select desirable traits. In this study, the micro- and ultra-structural and physiological features of leaves on wild type and leaf color mutants (dark green, rubescent, etiolated, albino) in A. andraeanum 'Sonate' were analyzed. Results show that chloroplasts of leaf color mutants exhibited abnormal morphology and distribution. Using next generation sequencing technology followed by de novo assembly, leaf transcriptomes comprising of 41,017 unigenes with an average sequence length of 768 bp were produced from wild type and rubescent mutant. From the 27,539 (67.1%) unigenes with annotated functions, 858 significantly differently expressed genes (DEGs) were identified, consisting of 446 up-regulated genes and 412 down-regulated genes. Genes that affect chloroplasts development and division, and chlorophyll biosynthesis were included in the down-regulated DEGs. Quantitative real-time PCR (qRT-PCR) analysis validated that the expression level of those genes was significantly lower in the rubescent, etiolated, and albino mutant compared to wild type plants, which concurs with the differences in micro- and ultra-structures and physiological features between these two types of plants. Conclusively, the leaf color formation is greatly affected by the activity of chloroplast development and pigment biosynthesis. And the possible formation pathway of leaf color mutant of A. andraeanum 'Sonate' is deduced based on our results.