[Genetic background of lily germplasm resources based on SSR markers].

To study the genetic background of lily (Lilium spp.) germplasm resources, and accurately evaluate and select excellent germplasm for genetic improvement of lily, we analyzed the genetic background of 62 lily germplasm accessions from 11 provinces of China by using simple sequence repeat (SSR) molecular markers. The results showed that 15 out of 83 pairs of lily SSR primers were polymorphic. A total of 157 allelic loci were amplified, with the number of alleles per locus ranging from 5 to 19 and the average number of effective alleles per locus being 4.162 8. The average observed heterozygosity and expected heterozygosity were 0.228 2 and 0.694 1, respectively. The average polymorphic information content was 0.678 8. The average Nei's diversity index and Shannon's information index were 0.694 1 and 1.594 9, respectively, indicating that the tested lily germplasm had high genetic diversity. The 62 germplasm accessions were classified into 5 groups by the unweighted pair group method with arithmetic mean (UPGMA) and into 3 groups by the principal component analysis. The two analyses revealed a geographic correlation among different groups. The majority of lily germplasm accessions from the same source tended to cluster together. The population structure analysis classified the lily accessions into 4 populations and 1 mixed population. The above results provide a theoretical basis and genetic resources for the precise identification and breeding of lily germplasm resources.

LiNAC100 contributes to linalool biosynthesis by directly regulating LiLiS in Lilium 'Siberia'.

MAIN CONCLUSION: The transcription factor LiNAC100 has a novel function of regulating floral fragrance by directly regulating linalool synthase gene LiLiS. Lilium 'Siberia', an Oriental hybrid, is renowned as both a cut flower and garden plant, prized for its color and fragrance. The fragrance comprises volatile organic compounds (VOCs), primarily monoterpenes found in the plant. While the primary terpene synthases in Lilium 'Siberia' were identified, the transcriptional regulation of these terpene synthase (TPS) genes remains unclear. Thus, understanding the regulatory mechanisms of monoterpene biosynthesis is crucial for breeding flower fragrance, thereby improving ornamental and commercial values. In this study, we isolated a nuclear-localized LiNAC100 transcription factor from Lilium 'Siberia'. The virus-induced gene silencing (VIGS) of LiNAC100 was found to down-regulate the expression of linalool synthase gene (LiLiS) and significantly inhibit linalool synthesis. Conversely, transient overexpression of LiNAC100 produced opposite effects. Additionally, yeast one-hybrid and dual-luciferase assays confirmed that LiNAC100 directly activates LiLiS expression. Our findings reveal that LiNAC100 plays a key role in monoterpene biosynthesis in Lilium 'Siberia', promoting linalool synthesis through the activation of LiLiS expression. These results offer insights into the molecular mechanisms of terpene biosynthesis in Lilium 'Siberia' and open avenues for biotechnological enhancement of floral scent.

Ferric reduction oxidase in Lilium pumilum affects plant saline-alkaline tolerance by regulating ROS homeostasis.

Ferric reduction oxidase (FRO) plays important roles in biotic and abiotic stress. However, the function of ferric reduction oxidase from Lilium pumilum in response to NaHCO3 is unknown. Here we report the functional characterization of ferric reduction oxidase 7 in Lilium pumilum (LpFRO7) in stresses. Under NaHCO3 stress, the LpFRO7 overexpression lines exhibited lower accumulation of reactive oxygen species (ROS), higher activities in antioxidant enzyme (CAT, SOD and POD) and ferrite reductase, resulting in improved tolerance compared to the wild type (WT). In order to determine the functional network of LpFRO7, it was confirmed by EMSA assays, Yeast one-hybrid assays and Dual luciferase reporter assays that LpbHLH115 transcription factor can bind to the promoter of LpFRO7. Yeast two-hybrid assays, BiFC, and LCI assays were performed to prove that LpFRO7 can interact with LpTrx. Combining these findings, we concluded that LpFRO7 affects plant saline-alkaline tolerance by regulating ROS homeostasis.

Screening and validation of optimal miRNA reference genes in different developing stages and tissues of Lilium henryi Baker.

Dynamic miRNA detection using the qRT-PCR technique requires appropriate reference genes to ensure data reliability. Previous studies have screened internal reference genes in plants during embryonic development and various stress treatment, involving relatively few tissues and organs. There is no relevant miRNA study in Lilium henryi Baker and limited research on the optimal miRNA reference genes in lilies, such as 5S, 18S, U6 and Actin. Twelve genes were selected as candidate reference genes whose expression stability was analyzed in petals at different developmental stages and other tissues using various algorithms, such as geNorm, NormFinder, BestKeeper, and Delta CT. The results revealed that the optimal combination of reference genes for Lilium henryi Baker petals at different developmental stages was osa-miR166m and osa-miR166a-3p, while that for different tissues of Lilium henryi Baker was osa-miR166g-3p and osa-miR166a-3p.Four important genes related to growth and development regulation, namely, osa-miR156a, osa-miR395b, osa-miR396a-3p, and osa-miR396a-5p, were selected for validation. The findings of the present study could contribute to future investigations onmiRNA expression and the related functions in Lilium henryi Baker while providing important references for the normalization of the miRNA expression in other varieties of lily.

Cloning and Functional Characterization of 2-C-methyl-D-erythritol-4-phosphate cytidylyltransferase (LiMCT) Gene in Oriental Lily (Lilium 'Sorbonne').

2-C-methyl-D-erythritol-phosphate cytidylyltransferase (MCT) is a key enzyme in the MEP pathway of monoterpene synthesis, catalyzing the generation of 4- (5'-pyrophosphate cytidine)-2-C-methyl-D-erythritol from 2-C-methyl-D-erythritol-4-phosphate. We used homologous cloning strategy to clone gene, LiMCT, in the MEP pathway that may be involved in the regulation of floral fragrance synthesis in the Lilium oriental hybrid 'Sorbonne.' The full-length ORF sequence was 837 bp, encoding 278 amino acids. Bioinformatics analysis showed that the relative molecular weight of LiMCT protein is 68.56 kD and the isoelectric point (pI) is 5.12. The expression pattern of LiMCT gene was found to be consistent with the accumulation sites and emission patterns of floral fragrance monoterpenes in transcriptome data (unpublished). Subcellular localization indicated that the LiMCT protein is located in chloroplasts, which is consistent with the location of MEP pathway genes functioning in plastids to produce isoprene precursors. Overexpression of LiMCT in Arabidopsis thaliana affected the expression levels of MEP and MVA pathway genes, suggesting that overexpression of the LiMCT in A. thaliana affected the metabolic flow of C5 precursors of two different terpene synthesis pathways. The expression of the monoterpene synthase AtTPS14 was elevated nearly fourfold in transgenic A. thaliana compared with the control, and the levels of carotenoids and chlorophylls, the end products of the MEP pathway, were significantly increased in the leaves at full bloom, indicating that LiMCT plays an important role in regulating monoterpene synthesis and in the synthesis of other isoprene-like precursors in transgenic A. thaliana flowers. However, the specific mechanism of LiMCT in promoting the accumulation of isoprene products of the MEP pathway and the biosynthesis of floral monoterpene volatile components needs further investigation.

HD-Zip I protein LlHOX6 antagonizes homeobox protein LlHB16 to attenuate basal thermotolerance in lily.

Homeodomain-leucine zipper (HD-Zip) I transcription factors are crucial for plant responses to drought, salt, and cold stresses. However, how they are associated with thermotolerance remains mostly unknown. We previously demonstrated that lily (Lilium longiflorum) LlHB16 (HOMEOBOX PROTEIN 16) promotes thermotolerance, whereas the roles of other HD-Zip I members are still unclear. Here, we conducted a transcriptomic analysis and identified a heat-responsive HD-Zip I gene, LlHOX6 (HOMEOBOX 6). We showed that LlHOX6 represses the establishment of basal thermotolerance in lily. LlHOX6 expression was rapidly activated by high temperature, and its protein localized to the nucleus. Heterologous expression of LlHOX6 in Arabidopsis (Arabidopsis thaliana) and overexpression in lily reduced their basal thermotolerance. In contrast, silencing LlHOX6 in lily elevated basal thermotolerance. Cooverexpressing or cosilencing LlHOX6 and LlHB16 in vivo compromised their functions in modulating basal thermotolerance. LlHOX6 interacted with itself and with LlHB16, although heterologous interactions were stronger than homologous ones. Notably, LlHOX6 directly bounds DNA elements to repress the expression of the LlHB16 target genes LlHSFA2 (HEAT STRESS TRANSCRIPTION FACTOR A2) and LlMBF1c (MULTIPROTEIN BRIDGING FACTOR 1C). Moreover, LlHB16 activated itself to form a positive feedback loop, while LlHOX6 repressed LlHB16 expression. The LlHOX6-LlHB16 heterooligomers exhibited stronger DNA binding to compete for LlHB16 homooligomers, thus weakening the transactivation ability of LlHB16 for LlHSFA2 and LlMBF1c and reducing its autoactivation. Altogether, our findings demonstrate that LlHOX6 interacts with LlHB16 to limit its transactivation, thereby impairing heat stress responses in lily.

Functional analysis of a lily SHORT VEGETATIVE PHASE ortholog in flowering transition and floral development.

Lilium is a commercially important genus of bulbous flowers, investigating the flowering molecular mechanisms is important for flowering regulation of lily. MADS-box SHORT VEGETATIVE PHASE (SVP) orthologs are involved in the flowering transition and floral organ differentiation in many plants. In this study, we identified an SVP ortholog from L. × formolongi (LfSVP), which was closely related to Arabidopsis SVP according to phylogenetic analysis. Tissue-specific expression patterns indicated that LfSVP expression levels peaked in the leaves and showed low expression levels in flowering tepals. Stage-dependent expression patterns of LfSVP showed high transcription level in the flowering induction stage under different photoperiods and exhibited transcription peak in the floral budding development stage under long days. Overexpressed LfSVP led to delayed flowering and floral organ defects in Arabidopsis independent of photoperiod. Tobacco rattle virus -induced gene silencing of LfSVP caused a strongly earlier flowering time and floral organ defects of L. × formolongi. Moreover, LfSVP can interact with L. × formolongi APETALA1 (AP1) in both yeast and tobacco cells, and the two may interact to regulate floral organ differentiation. In conclusion, LfSVP is a flowering repressor and may be involved in the regulation of floral organ differentiation. This study will be helpful for the molecular breeding of short-life-period and rich floral patterns lily varieties.

Determination of Volatile Organic Compounds and Endogenous Extracts and Study of Expression Patterns of TPS and BSMT in the Flowers of Seven Lilium Cultivars.

Lily is one of the most important cut flowers in the world, with a rich floral fragrance. To further explore the fragrance emission mechanisms of lily cultivars, headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and organic solvent extraction-gas chromatography-mass spectrometry (OSE-GC-MS) were used to unveil the volatile organic compounds (VOCs) and endogenous extracts of seven lily cultivars. Furthermore, real-time quantitative PCR (qRT-PCR) was used to determine the expression levels of two key genes (TPS and BSMT) related to the biosynthesis of monoterpenoids and methyl benzoate. The results show that forty-five VOCs were detected in the petals of seven lily cultivars, and the main compounds were monoterpenoids and phenylpropanoids/benzenoids. Dichloromethane was the best solvent for extracting the endogenous extracts of Lilium 'Viviana' petals and eighteen endogenous extracts were detected using dichloromethane to extract the petals of seven lily cultivars. Each compound's emission ratio (natural logarithm of the ratio of VOC content to endogenous extract content) was calculated, and linear regression analyses between emission ratios and boiling points were conducted. Significant linear negative correlations existed between the emission ratios and boiling points of compounds, and the regression equations' coefficients of determination (R2) were all greater than 0.7. TPS was expressed highly in 'Viviana', 'Pink News', and 'Palazzo', and BSMT was expressed highly in 'Pink News' and 'Palazzo'. Correlation analyses between the gene expression levels and the monoterpenoids and methyl benzoate contents found that the TPS expression levels have strong positive correlations with monoterpenoids content, while no correlations were found between the expression levels of BSMT and the contents of methyl benzoate. This study lays the foundation for research on the release patterns of VOCs in the flowers of Lilium, and the breeding of lilies for their floral fragrance.

Integrated transcriptome and metabolome revealed the drought responsive metabolic pathways in Oriental Lily (Lilium L.).

Objective: Lily is an essential ornamental flowering species worldwide. Drought stress is a major constraint affecting the morphology and physiology and lily leaves and flowers. Therefore, understanding the molecular mechanism underlying lily response to drought stress is important. Method: Transcriptome and metabolome analysis were performed on Oriental Lily subjected to drought stress. Result: Most transcription factors and metabolites yielded by the conjoint analysis displayed a downregulated expression pattern. Differential genes and metabolites mainly co-enriched in glycolic pathways related to sugars, such as galactose, and sucrose, glycolysis and gluconeogenesis, indicating that drought stress reduced the sugar metabolism level of Oriental Lily. Combined with transcriptome and metabolome data, nine pairs of differentially expressed metabolites and the genes (p < 0.05) were obtained. Interestingly, a gene named TRINITY_DN2608 (encoding a type of alpha-D-glucose) cloned and its overexpression lines in Arabidopsis thaliana was generated. Overexpression of TRINITY_DN2608 gene elevated the susceptibility to drought stress possibly by suppressing the glucose level. Conclusion: The enrichment of sugar-related pathways advocates the potential role of glucose metabolism in drought stress. Our study provides theoretical information related to the glucose-mediated drought response and would be fruitful in future lily breeding programs.

Regulatory mechanism of the miR172e-LbrAP2 module during the vegetative growth phase transition in Lilium.

MAIN CONCLUSION: It was proved for the first time that the miR172e-LbrAP2 module regulated the vegetative growth phase transition in Lilium, which provided a new approach to shorten the juvenile stage of Lilium, improved the reproduction rate, and reduced the propagation cost of Lilium commercial bulbs. Lilium is an ornamental bulb plant that takes at least 3 years to cultivate into commercial seed bulbs under natural conditions. The aim of this study was to shorten the Lilium expansion cycle. In this study, the growth cycle of lily tubers induced by low temperature of 15 °C was significantly shorter than that of tubers grown at a conventional temperature. Quantitative real-time PCR analysis showed that the expression patterns of miR172e and LbrAP2 were negatively correlated. GUS histochemical staining confirmed that miR172e and LbrAP2 in tobacco leaves interacted with each other after co-transformation. The shear sites of miR172e and its target gene, LbrAP2, upon binding, were identified by RLM 5' RACE analysis. In addition, miR172e and LbrAP2 showed opposite expression patterns after the transformation of Arabidopsis. miR172e overexpression accelerated the transition from juvenile to adult plants, whereas LbrAP2 overexpression inhibited this process, thus indicating that miR172e negatively regulated the target gene LbrAP2. Upregulation of the transcription factor LbrAP2 delayed the phase transition of plants, whereas miR172 inhibited the transcriptional translation of LbrAP2, thereby accelerating the phase transition. Low-temperature treatment of Lilium bulbs can shorten Lilium development, which provides a new approach to accelerating Lilium commercial bulb breeding and reducing breeding costs.

Low LdMYB12 expression contributes to petal spot deficiency in Lilium davidii var. unicolor.

Petal spots are widespread in plants, they are important for attracting pollinators and as economic traits in crop breeding. However, the genetic and developmental control of petal spots has seldom been investigated. To further clarify the development of petal spots formation, we performed comparative transcriptome analysis of Lilium davidii var. unicolor and Lilium davidii petals at the full-bloom stage. In comparison with the parental species L. davidii, petals of the lily variety L. davidii var. unicolor do not have the distinct anthocyanin spots. We show that among 7846 differentially expressed genes detected, LdMYB12 was identified as a candidate gene contributing to spot formation in lily petals. The expression level of LdMYB12 in the petals of L. davidii was higher than that in L. davidii var. unicolor petals. Moreover, overexpression of LdMYB12 led to the appearance of spots on the petals of L. davidii var. unicolor, accompanied by increased expression of anthocyanin synthesis-related genes. Taken together, these results indicate that abnormal expression of LdMYB12 contributes to petal spot deficiency in L. davidii var. unicolor.

Cryopreservation of Lilium candidum germplasm: analysis of pre- and post-freeze treatments.

BACKGROUND: Lilium candidum L. is a perennial ornamental plant that has various medicinal properties and is used in the cosmetic industry. The species is facing threats from urbanization and climate change and requires urgent protection. The most secure and efficient technology for the long-term storage of plant genetic resources is cryopreservation, which involves preserving genetic material at extremely low temperatures. OBJECTIVE: Today, plant biodiversity is endangered because of the narrowing of its natural distribution areas and/or destruction for different purposes. This study concentrated on creating a cryopreservation process using shoot tips and calluses as explant sources for the long-term conservation of L. candidum species. MATERIALS AND METHODS: Populations of L. candidum naturally distributed from three different regions of Turkey (Kepsut, Balikesir; the area surrounding Bafa Lake, Aydin; and Fethiye-Mugla) were grown in vitro to supply shoot tip and callus explants. Prior to freezing by droplet-vitrification and vitrification techniques, shoot tips and calluses were treated with MS nutritional medium supplemented with 0.4 M sucrose 7 g per L agar and plant vitrification solution 2 (PVS2). RESULTS: Cryopreserved shoot tips showed the highest levels of regeneration (71.8%) after a PVS2 treatment of 90 min, while calluses showed the highest levels of regrowth (63.9%) after a PVS2 exposure of 60 min. CONCLUSION: High levels of regrowth are produced when the various cryopreservation procedures described here are used to preserve both shoot tip and callus explants. This potentially makes the method promising for the long-term preservation of endangered L. candidum varieties. Doi.org/10.54680/fr23510110512.

A Modified Method for Transient Transformation via Pollen Magnetofection in Lilium Germplasm.

Lily (Lilium spp.) is a popular ornamental plant. Traditional genetic transformation methods have low efficiency in lily, thus development of a high-efficiency genetic transformation system is important. In this study, a novel transient transformation method involving pollen magnetofection was established and optimized pollen viability, and exogenous gene expression in magnetofected pollen and that of different germplasm were assessed. The highest germination percentage of Lilium regale pollen was 85.73% in medium containing 100 g/L sucrose, 61.5 mg/L H3BO3, and 91.5 mg/L CaCl2. A 1:4 ratio of nanomagnetic beads to DNA plasmid and transformation time of 0.5 h realized the highest transformation efficiency (88.32%). The GFP activity in transformed pollen averaged 69.66%, while that of the control pollen was 0.00%. In contrast to the control, transgenic seedlings obtained by pollination with magnetofected pollen showed strong positive GUS activity with 56.34% transformation efficiency. Among the lily germplasm tested, 'Sweet Surrender' and L. leucanthum had the highest transformation efficiency (85.80% and 54.47%), whereas L. davidii var. willmottiae was not successfully transformed. Transformation efficiency was positively correlated with pollen equatorial diameter and negatively correlated with polar axis/equatorial diameter ratio. The results suggest that pollen magnetofection-mediated transformation can be applied in Lilium but might have species or cultivar specificity.

Lilium Gray Mold Suppression Conferred by the Host Antimicrobial Protein LsGRP1 Involves Main Pathogen-Targeted Manipulation of the Nonantimicrobial Region LsGRP1N.

Antimicrobial protein LsGRP1 protects Lilium from gray mold mainly caused by the destructive pathogen Botrytis elliptica; however, its nonantimicrobial region LsGRP1N conversely promotes spore germination of this fungus. By assaying the effects of LsGRP1N, LsGRP1, and the combination of LsGRP1N and the antimicrobial region LsGRP1C on fungal spore germination, hyphal growth, and Lilium gray mold development, LsGRP1N was found to improve the LsGRP1C sensitivity of B. elliptica and disease suppression by LsGRP1C. B. elliptica cell vitality assays indicated that LsGRP1N pretreatment uniquely enhanced the lethal efficiency of LsGRP1C compared to the control peptides. In addition, LsGRP1N-treated B. elliptica was demonstrated to lower infection-related gene expression and increase host-defense-eliciting activity, as indicated by reverse transcription quantitative polymerase chain reaction and histochemical-staining-based callose detection results, respectively. Therefore, LsGRP1N showed a novel mode of action for antimicrobial proteins by manipulating the main pathogen, which facilitated the development of target-specific and dormant microbe-eradicating antimicrobial agents.

Molecular mechanisms of miR172a and its target gene LbrTOE3 regulating maturation in Lilium.

MAIN CONCLUSION: Lbr-miR172a could promote the growth phase transition and shorten maturation in Lilium, while LbrTOE3 inhibited this process and prolonged the growth period. Lilium is an ornamental flower with high economic value for both food and medicinal purposes. However, under natural conditions, Lilium bulbs take a long time and cost more to grow to commercial size. This research was conducted to shorten the maturation time by subjecting Lilium bulbs to alternating temperature treatment. To explore the molecular mechanism of the vegetative phase change (VPC) in Lilium after variable temperature treatment, the key module miR172a-TOE3 was selected based on a combined omics analysis. Gene cloning and transgene functional validation showed that overexpression of Lbr-mir172a promoted a phase change, while overexpression of LbrTOE3 inhibited this process. Subcellular localization and transcriptional activation assays indicated that LbrTOE3 was predominantly localized in the nucleus and showed transcriptional activity. In situ hybridization showed that LbrTOE3 expression was significantly downregulated after alternating temperature treatment. This study elucidates the molecular mechanisms of the phase transition of Lilium and provides a scientific basis for the phase transition in other plants.

Identification and complete genome sequence of iris potyvirus A, which causes dwarfing and foliar chlorosis with mosaic or mottle disease symptoms on lily (Lilium lancifolium Thunb.) in China.

Lily plants (Lilium lancifolium Thunb.) exhibiting dwarfing and foliar chlorosis with mosaic or mottle disease symptoms were found in Anhui Province, China. We used high-throughput sequencing of small RNA to survey the virus in the lily cultivation region of Anhui Province. Here, we report the identification and complete genome sequence of the viral agent. It contains 9733 nucleotides, excluding the poly(A) tail, and encodes a polyprotein of 3063 amino acids. The complete polyprotein ORF shows 98.92% amino acid sequence identity with that of iris potyvirus A (GenBank MH898493). Phylogenetic analysis of coat protein sequences placed the viral agent close to members of the genus Potyvirus in the family Potyviridae, and it was therefore provisionally named iris potyvirus A isolate Anhui (IrPVA-Anhui). This is the first complete genome sequence of IrPVA-Anhui from lily plant, for which only a partial sequence from Iris domestica has been reported previously. Comparative analysis of this genome sequence with those of closely related potyviruses identified nine cleavage sites and the conserved motifs typical of potyviruses. Subsequent virus identification was performed using serological assays (ELISA and antibody-based lateral flow assays), molecular methods (RT-PCR), and a pathogenicity test. Virus particles with a length of about 700 nm, similar to viruses in the genus Potyvirus, were observed via transmission electron microscope (TEM). We back-inoculated healthy plants of multiple species to investigate the host range of the virus. It infected the original host, Iris domestica, and Nicotiana benthamiana but not Triticum aestivum, Pisum sativum, Chenopodium amaranticolor, or Datura stramonium. This is the first report of natural IrPVA-Anhui infection of lily plants in China, providing a scientific basis for IrPVA-Anhui control in future lily plantings.

Assembly and Comparative Analysis of the Complete Mitochondrial Genome of Two Species of Calla Lilies (Zantedeschia, Araceae).

In this study, the mitochondrial genomes of two calla species, Zantedeschia aethiopica Spreng. and Zantedeschia odorata Perry., were assembled and compared for the first time. The Z. aethiopica mt genome was assembled into a single circular chromosome, measuring 675,575 bp in length with a 45.85% GC content. In contrast, the Z. odorata mt genome consisted of bicyclic chromosomes (chromosomes 1 and 2), measuring 719,764 bp and exhibiting a 45.79% GC content. Both mitogenomes harbored similar gene compositions, with 56 and 58 genes identified in Z. aethiopica and Z. odorata, respectively. Analyses of codon usage, sequence repeats, gene migration from chloroplast to mitochondrial, and RNA editing were conducted for both Z. aethiopica and Z. odorata mt genomes. Phylogenetic examination based on the mt genomes of these two species and 30 other taxa provided insights into their evolutionary relationships. Additionally, the core genes in the gynoecium, stamens, and mature pollen grains of the Z. aethiopica mt genome were investigated, which revealed maternal mitochondrial inheritance in this species. In summary, this study offers valuable genomic resources for future research on mitogenome evolution and the molecular breeding of calla lily.

A Na+/H+ antiporter-encoding salt overly sensitive 1 gene, LpSOS1, involved in positively regulating the salt tolerance in Lilium pumilum.

Lilium pumilum has a strong salt tolerance. However, the molecular mechanism underlying its salt tolerance remains unexplored. Here, LpSOS1 was cloned from L. pumilum and found to be significantly enriched at high NaCl concentrations (100 mM). In tobacco epidermal cells, localization analysis showed that the LpSOS1 protein was primarily located in the plasma membrane. Overexpression of LpSOS1 resulted in up-regulation of salt stress tolerance in Arabidopsis, as indicated by reduced malondialdehyde levels and Na+/K+ ratio, and increased activity of antioxidant reductases (including superoxide dismutase, peroxidase, and catalase). Treatment with NaCl resulted in improved growth, as evidenced by increased biomass, root length, and lateral root growth, in both sos1 mutant (atsos1) and wild-type (WT) Arabidopsis plants that overexpressed LpSOS1, Under NaCl treatment,atsos1 and WT Arabidopsis plants overexpressing LpSOS1 exhibited better growth, with higher biomass, root length, and lateral root quantity, whereas in the absence of LpSOS1 overexpression, the plants of both lines were wilted and chlorotic and even died under salt stress. When exposed to salt stress, the expression of stress-related genes was notably upregulated in the LpSOS1 overexpression line of Arabidopsis as compared to the WT. Our findings indicate that LpSOS1 enhances salt tolerance in plants by regulating ion homeostasis, reducing Na+/K+ ratio, thereby protecting the plasma membrane from oxidative damage caused by salt stress, and enhancing the activity of antioxidant enzymes. Therefore, the increased salt tolerance conferred by LpSOS1 in plants makes it a potential bioresource for breeding salt-tolerant crops. Further investigation into the mechanisms underlying lily's resistance to salt stress would be advantageous and could serve as a foundation for future molecular improvements.

Streptomyces longhuiensis sp. nov, a novel species isolated from soil of Lilium brownii in Hunan Province, PR China.

An actinobacterium strain, designated BH-MK-02T, was isolated from the soil of Lilium brownii. The taxonomic position was determined using a polyphasic approach. Strain BH-MK-02T grew well on International Streptomyces Project series media and formed well-developed, branched substrate hyphae and aerial mycelium that differentiated into straight spore chains with a wrinkled surface. The diagnostic diamino acid was ll-diaminopimelic acid. The major menaquinones were MK-9(H4), MK-9(H6) and MK-9(H8). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylglycerol and unidentified lipid spots. The predominant fatty acids were anteiso-C15 : 0, iso-C16 : 0, C16 : 0 and C16 : 1 ω7c/C16 : 1 ω6c. The phenotypic characteristics of strain BH-MK-02T indicated that it belonged to the genus Streptomyces. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain BH-MK-02T was most closely related to Streptomyces aureus CGMCC 4.1833T (99.7 %). However, the average nucleotide identity and digital DNA-DNA hybridization values between the whole-genome sequences of strain BH-MK-02T and S. aureus CGMCC 4.1833T were 78.1 and 23.2 %, respectively, below the 96.7 and 70 % cut-off points respectively recommended for delineating Streptomyces species. Furthermore, the novel isolate could be distinguished from S. aureus CGMCC 4.1833T by morphological, physiological and biochemical characteristics. Based on all these data, strain BH-MK-02T (=MCCC 1K06237T=JCM 34789T) clearly represents a novel species within the genus Streptomyces, for which the name Streptomyces longhuiensis sp. nov. is proposed.

LhANS-rr1, LhDFR, and LhMYB114 Regulate Anthocyanin Biosynthesis in Flower Buds of Lilium 'Siberia'.

The bulb formation of Lilium is affected by many physiological and biochemical phenomena, including flower bud differentiation, starch and sucrose accumulation, photoperiod, carbon fixation, plant hormone transduction, etc. The transcriptome analysis of flower buds of Lilium hybrid 'Siberia' at different maturity stages showed that floral bud formation is associated with the accumulation of anthocyanins. The results of HPLC-MS showed that cyanidin is the major anthocyanin found in Lilium 'Siberia'. Transcriptome KEGG enrichment analysis and qRT-PCR validation showed that two genes related to flavonoid biosynthesis (LhANS-rr1 and LhDFR) were significantly up-regulated. The functional analysis of differential genes revealed that LhMYB114 was directly related to anthocyanin accumulation among 19 MYB transcription factors. Furthermore, the qRT-PCR results suggested that their expression patterns were very similar at different developmental stages of the lily bulbs. Virus-induced gene silencing (VIGS) revealed that down-regulation of LhANS-rr1, LhDFR, and LhMYB114 could directly lead to a decrease in anthocyanin accumulation, turning the purple phenotype into a white color. Moreover, this is the first report to reveal that LhMYB114 can regulate anthocyanin accumulation at the mature stage of lily bulbs. The accumulation of anthocyanins is an important sign of lily maturity. Therefore, these findings have laid a solid theoretical foundation for further discussion on lily bulb development in the future.