BACKGROUND: Invertases (INVs) are key enzymes in sugar metabolism, cleaving sucrose into glucose and fructose and playing an important role in plant development and the stress response, however, the INV gene family in passion fruit has not been systematically reported.
RESULTS: In this study, a total of 16 PeINV genes were identified from the passion fruit genome and named according to their subcellular location and chromosome position. These include six cell wall invertase (CWINV) genes, two vacuolar invertase (VINV) genes, and eight neutral/alkaline invertase (N/AINV) genes. The gene structures, phylogenetic tree, and cis-acting elements of PeINV gene family were predicted using bioinformatics methods. Results showed that the upstream promoter region of the PeINV genes contained various response elements; particularly, PeVINV2, PeN/AINV3, PeN/AINV5, PeN/AINV6, PeN/AINV7, and PeN/AINV8 had more response elements. Additionally, the expression profiles of PeINV genes under different abiotic stresses (drought, salt, cold temperature, and high temperature) indicated that PeCWINV5, PeCWINV6, PeVINV1, PeVINV2, PeN/AINV2, PeN/AINV3, PeN/AINV6, and PeN/AINV7 responded significantly to these abiotic stresses, which was consistent with cis-acting element prediction results. Sucrose, glucose, and fructose are main soluble components in passion fruit pulp. The contents of total soluble sugar, hexoses, and sweetness index increased significantly at early stages during fruit ripening. Transcriptome data showed that with an increase in fruit development and maturity, the expression levels of PeCWINV2, PeCWINV5, and PeN/AINV3 exhibited an up-regulated trend, especially for PeCWINV5 which showed highest abundance, this correlated with the accumulation of soluble sugar and sweetness index. Transient overexpression results demonstrated that the contents of fructose, glucose and sucrose increased in the pulp of PeCWINV5 overexpressing fruit. It is speculated that this cell wall invertase gene, PeCWINV5, may play an important role in sucrose unloading and hexose accumulation.
CONCLUSIONS: In this study, we systematically identified INV genes in passion fruit for the first time and further investigated their physicochemical properties, evolution, and expression patterns. Furthermore, we screened out a key candidate gene involved in hexose accumulation. This study lays a foundation for further study on INV genes and will be beneficial on the genetic improvement of passion fruit breeding.

East Asian Passiflora virus (EAPV) causes passionfruit woodiness disease, a major threat limiting passionfruit production in eastern Asia, including Taiwan and Vietnam. In this study, an infectious cDNA clone of a Taiwanese severe isolate EAPV-TW was tagged with a green fluorescent protein (GFP) reporter to monitor the virus in plants. Nicotiana benthamiana and yellow passionfruit plants inoculated with the construct showed typical symptoms of EAPV-TW. Based on our previous studies on pathogenicity determinants of potyviral HC-Pros, a deletion of six amino acids (d6) alone and its association with a point mutation (F8I, simplified as I8) were conducted in the N-terminal region of the HC-Pro gene of EAPV-TW to generate mutants of EAPV-d6 and EAPV-d6I8, respectively. The mutant EAPV-d6I8 caused infection without conspicuous symptoms in N. benthamiana and yellow passionfruit plants, while EAPV-d6 still induced slight leaf mottling. EAPV-d6I8 was stable after six passages under greenhouse conditions and displayed a zigzag pattern of virus accumulation, typical of a beneficial protective virus. The cross-protection effectiveness of EAPV-d6I8 was evaluated in both N. benthamiana and yellow passionfruit plants under greenhouse conditions. EAPV-d6I8 conferred complete cross-protection (100%) against the wild-type EAPV-TW-GFP in both N. benthamiana and yellow passionfruit plants, as verified by no severe symptoms, no fluorescent signals, and PCR-negative status for GFP. Furthermore, EAPV-d6I8 also provided complete protection against Vietnam\'s severe strain EAPV-GL1 in yellow passionfruit plants. Our results indicate that the attenuated mutant EAPV-d6I8 has great potential to control EAPV in Taiwan and Vietnam via cross-protection.

BACKGROUND: The calmodulin (CaM) and calmodulin-like (CML) proteins play regulatory roles in plant growth and development, responses to biotic and abiotic stresses, and other biological processes. As a popular fruit and ornamental crop, it is important to explore the regulatory mechanism of flower and fruit development of passion fruit.
RESULTS: In this study, 32 PeCaM/PeCML genes were identified from passion fruit genome and were divided into 9 groups based on phylogenetic analysis. The structural analysis, including conserved motifs, gene structure and homologous modeling, illustrates that the PeCaM/PeCML in the same subgroup have relative conserved structural features. Collinearity analysis suggested that the expansion of the CaM/CML gene family likely took place mainly by segmental duplication, and the whole genome replication events were closely related with the rapid expansion of the gene group. PeCaM/PeCMLs were potentially required for different floral tissues development. Significantly, PeCML26 had extremely high expression levels during ovule and fruit development compared with other PeCML genes, suggesting that PeCML26 had potential functions involved in the development of passion fruit flowers and fruits. The co-presence of various cis-elements associated with growth and development, hormone responsiveness, and stress responsiveness in the promoter regions of these PeCaM/PeCMLs might contribute to their diverse regulatory roles. Furthermore, PeCaM/PeCMLs were also induced by various abiotic stresses. This work provides a comprehensive understanding of the CaM/CML gene family and valuable clues for future studies on the function and evolution of CaM/CML genes in passion fruit.
CONCLUSIONS: A total of 32 PeCaM/PeCML genes were divided into 9 groups. The PeCaM/PeCML genes showed differential expression patterns in floral tissues at different development stages. It is worth noting that PeCML26, which is highly homologous to AtCaM2, not only interacts with multiple BBR-BPC TFs, but also has high expression levels during ovule and fruit development, suggesting that PeCML26 had potential functions involved in the development of passion fruit flowers and fruits. This research lays the foundation for future investigations and validation of the potential function of PeCaM/PeCML genes in the growth and development of passion fruit.

A polyphasic approach was applied to characterize taxonomically a novel endophytic bacterial strain, designated as EP178T, which was previously isolated from Passiflora incarnata leaves and characterized as plant-growth promoter. The strain EP178T forms Gram stain-negative and rod-shaped cells, and circular and yellow-pigmented colonies. Its growth occurs at 10-37 °C, at pH 6.0-8.0, and tolerates up to 7% (w/v) NaCl. The major cellular fatty acids found were summed feature 8 (C18:1 ω7c), summed feature 3 (C16:1 ω6c /C16:1 ω7c), and C16:0, and the predominant ubiquinone was Q-9. The phylogenetic and nucleotide-similarity analysis with 16S rRNA gene sequences showed that strain EP178T belongs to Pseudomonas genus. The genomic-based G + C content was 65.5%. The average nucleotide identity and digital DNA-DNA hybridization values between strains EP178T and the closest type strain, P. oryzihabitans DSM 6835T, were 92.6% and 52.2%, respectively. Various genes associated with plant-growth promoting mechanisms were annotated from genome sequences. Based on the phenotypic, genomic, phylogeny and chemotaxonomic data, strain EP178T represents a new species of the genus Pseudomonas, for which the name Pseudomonas flavocrustae sp. nov. was proposed. The type strain is EP178T (= CBMAI 2609T = ICMP 24844T = MUM 23.01T).

Type 2 diabetes mellitus (T2DM) is a major global public health concern, prompting the ongoing search for new treatment options. Medicinal plants have emerged as one such alternative. Our objective was to evaluate the antidiabetic effect of an extract from the leaves of Passiflora ligularis (P. ligularis). For this purpose, T2DM was first induced in mice using a high-fat diet and low doses of streptozotocin. Subsequently, an aqueous extract or an ethanolic extract of P. ligularis leaves was administered for 21 days. The following relevant results were found: fasting blood glucose levels were reduced by up to 41%, and by 29% after an oral glucose overload. The homeostasis model assessment of insulin resistance (HOMA-IR) was reduced by 59%. Histopathologically, better preservation of pancreatic tissue was observed. Regarding oxidative stress parameters, there was an increase of up to 48% in superoxide dismutase (SOD), an increase in catalase (CAT) activity by 35% to 80%, and a decrease in lipid peroxidation (MDA) by 35% to 80% in the liver, kidney, or pancreas. Lastly, regarding the lipid profile, triglycerides (TG) were reduced by up to 30%, total cholesterol (TC) by 35%, and low-density lipoproteins (LDL) by up to 32%, while treatments increased high-density lipoproteins (HDL) by up to 35%. With all the above, we can conclude that P. ligularis leaves showed antihyperglycemic, hypolipidemic, and antioxidant effects, making this species promising for the treatment of T2DM.

The species Passiflora alata, P. cincinnata, and P. edulis have great economic value due to the use of their fruits for human consumption. In this study, we compared the repetitive genome fractions of these three species. The compositions of the repetitive DNA of these three species\' genomes were analyzed using clustering and identification of the repetitive sequences with RepeatExplorer. It was found that repetitive DNA content represents 74.70%, 66.86%, and 62.24% of the genome of P. alata, P. edulis, and P. cincinnata, respectively. LTR Ty3/Gypsy retrotransposons represent the highest genome proportions in P. alata and P. edulis, while Ty1/Copia comprises the largest proportion of P. cincinnata genome. Chromosomal mapping by Fluorescent In Situ Hybridization (FISH) showed that LTR retrotransposons have a dispersed distribution along chromosomes. The subtelomeric region of chromosomes is where 145 bp satellite DNA is located, suggesting that these elements may play important roles in genome structure and organization in these species. In this work, we obtained the first global characterization of the composition of repetitive DNA in Passiflora, showing that an increase in genome size is related to an increase in repetitive DNA, which represents an important evolutionary route for these species.

Canine fear of fireworks is a common problem worldwide, with serious implications for the welfare of both dogs and their owners. Therapies for the problem are available, and herbal and nutraceutical agents are increasingly suggested by professionals; nonetheless, studies on their real efficacy in reducing firework fear are lacking. In a randomised, double-blinded, placebo-controlled study, 44 dogs (25 in the \"supplement\" group and 19 in the \"placebo\" group) completed a long-term continuous treatment with either a supplement made of tryptophan, valerian, and passiflora or a placebo, including two real exposures to fireworks (on 2020 Christmas and 2021 New Years\' Eve, after 42 and 48 days of treatment, respectively). Owners of both groups received the same general environmental management and food/toy offering recommendations for trying with their dogs on those nights. Behavioural (measured by LSSS-Lincoln Sound Sensitivity Scale and PANAS-Positive and Negative Activation scale, as rated by the owners) and stress (measured via salivary cortisol measures) reactions were evaluated. Significantly greater fear decrease (LSSS) was recorded in the \"supplement\" dogs, as compared to the \"placebo\" group. Cortisol dosages on New Year\'s Eve (\"noisy\" night) were in line with behavioural results; \"supplement\" dogs showed a smaller increase in the stress response from 22:30 to 00:30 h on New Year\'s Eve and a greater decrease in their stress response from 02:30 h to 10:30 h on New Year\'s Day compared to \"placebo\" dogs. Smaller cortisol levels were also shown by \"supplement\" dogs than \"placebo\" dogs on a controlled \"quiet night\" (27th December). Owners\' rates on PANAS remained stable during the whole period of therapy for both groups. The evaluated supplement, a combination of tryptophan, valerian, and passiflora, showed satisfactory results and rare side effects when treating dogs fearful of fireworks.

The Passiflora genus is recognised for its ethnopharmacological, sensorial, and nutritional significance. Yet, the screening of its dietary and bioactive molecules has mainly targeted hydrophilic metabolites. Following the PRISMA-P protocol, this review assessed the current knowledge on carotenoid composition and analysis within Passiflora, examining 968 records from seven databases and including 17 studies focusing on carotenoid separation and identification in plant parts. Those publications originated in America and Asia. P. edulis was the most frequently examined species of a total of ten, while pulp was the most studied plant part (16 studies). Carotenoid analysis involved primarily high-performance liquid chromatography separation on C18 columns and detection using diode array detectors (64.71%). Most studies identified the provitamin A β-carotene and xanthophylls lutein and zeaxanthin, with their geometric configuration often neglected. Only one study described carotenoid esters. Besides the methodology\'s insufficient description, the lack of use of more accurate techniques and practices led to a high risk of bias in the carotenoid assignment in 17.65% of the articles. This review highlights the opportunity to broaden carotenoid studies to other species and parts within the diverse Passiflora genus, especially to wild, locally available fruits, which may have a strategic role in enhancing food diversity and security amidst climatic changes. Additionally, it urges the use of more accurate and efficient analytical methods based on green chemistry to better identify Passiflora carotenoids.

This study involved the design and synthesis of a series of novel 4-chromanone-derived compounds. Their in vivo anti-cucumber mosaic virus (CMV) activity in field trials against CMV disease in Passiflora spp. was then assessed. Bioassay results demonstrated that compounds 7c and 7g exhibited remarkable curative effects and protection against CMV, with inhibition rates of 57.69% and 51.73% and 56.13% and 52.39%, respectively, surpassing those of dufulin and comparable to ningnanmycin. Field trials results indicated that compound 7c displayed significant efficacy against CMV disease in Passiflora spp. (passion fruit) after the third spraying at a concentration of 200 mg/L, with a relative control efficiency of 47.49%, surpassing that of dufulin and comparable to ningnanmycin. Meanwhile, nutritional quality test results revealed that compound 7c effectively enhanced the disease resistance of Passiflora spp., as evidenced by significant increases in soluble protein, soluble sugar, total phenol, and chlorophyll contents in Passiflora spp. leaves as well as improved the flavor and taste of Passiflora spp. fruits, as demonstrated by notable increases in soluble protein, soluble sugar, soluble solid, and vitamin C contents in Passiflora spp. fruits. Additionally, a transcriptome analysis revealed that compound 7c primarily targeted the abscisic acid (ABA) signaling pathway, a crucial plant hormone signal transduction pathway, thereby augmenting resistance against CMV disease in Passiflora spp. Therefore, this study demonstrates the potential application of these novel 4-chromanone-derived compounds as effective inducers of plant immunity for controlling CMV disease in Passiflora spp. in the coming decades.

Passiflora tripartita var. mollissima, known locally as poro-poro, is an important native fruit used in traditional Peruvian medicine with relevant agro-industrial and pharmaceutical potential for its antioxidant capacity for human health. However, to date, only a few genetic data are available, which limits exploring its genetic diversity and developing new genetic studies for its improvement. We report the poro-poro plastid genome to expand the knowledge of its molecular markers, evolutionary studies, molecular pathways, and conservation genetics. The complete chloroplast (cp) genome is 163,451 bp in length with a typical quadripartite structure, containing a large single-copy region of 85,525 bp and a small single-copy region of 13,518 bp, separated by a pair of inverted repeat regions (IR) of 32,204 bp, and the overall GC content was 36.87%. This cp genome contains 128 genes (110 genes were unique and 18 genes were found duplicated in each IR region), including 84 protein-coding genes, 36 transfer RNA-coding genes, eight ribosomal RNA-coding genes, and 13 genes with introns (11 genes with one intron and two genes with two introns). The inverted repeat region boundaries among species were similar in organization, gene order, and content, with a few revisions. The phylogenetic tree reconstructed based on single-copy orthologous genes and maximum likelihood analysis demonstrates poro-poro is most closely related to Passiflora menispermifolia and Passiflora oerstedii. In summary, our study constitutes a valuable resource for studying molecular evolution, phylogenetics, and domestication. It also provides a powerful foundation for conservation genetics research and plant breeding programs. To our knowledge, this is the first report on the plastid genome of Passiflora tripartita var. mollissima from Peru.