Healthy leaves of Bambusa sp. collected from Panchrukhi, Palampur, District Kangra of Himachal Pradesh, India, on 4 October 2021 were placed in sterile polythene bags and transported carefully to the laboratory. The surface adherents were removed after thorough washing under tap water. Then, bigger leaves were chopped into small pieces and subjected to surface sterilization following a modified method by Dobranic et al. (1995). Concisely, bamboo leaves were first dipped in 70% ethanol for 5 s, followed by 4% sodium hypochlorite for 90 s, and later rinsed with sterile water for 10 s (four times). These surface sterilized leaves were cut into small pieces using a sterilized sharp blade and inoculated on potato dextrose agar (PDA) plates. These plates were kept at 25°C until any vegetative growth appeared from the inoculated tissues. Individual colonies arising from inoculated tissues were transferred to fresh PDA plates by hyphal tipping and allowed to grow (Bills and Polishook, 1992). Furthermore, pure culture was raised using a single spore isolation technique. Colony characteristics of this isolate were studied on PDA and synthetic nutrient agar (SNA). Methuen’s Handbook of Color was referred to recording the colors of the colonies on different agar media (Kornerup and Wanscher, 1978). Microscopic structures of the isolates were recorded from pure culture using staining cum-mounting medium, lactophenol cotton blue, under a Carl Zeiss Image Analyzer 2 (Germany) microscope. Measurements and photomicrographs of the fungal structures were recorded using Axiovision Rel 4.8 software and Digi-Cam attached with Carl Zeiss Image Analyzer 2 microscope. The holotype specimen is deposited and accessioned in Ajrekar Mycological Herbarium (AMH 10381), and ex-type pure culture is deposited and accessioned in the National Fungal Culture Collection of India (NFCCI 5145).

Genomic DNA was extracted from pure colonies raised from single spore isolation on PDA Petri plates. After approximately 1 week of incubation, DNA extraction was performed by a simple, easy, and rapid DNA extraction protocol using FastPrep®24 tissue homogenizer (MP Biomedicals GmbH, Eschwege, Germany; Aamir et al., 2015). The amplification and sequencing of tef-1α, rpb2, and LSU gene regions were carried out. The primers involved in amplification and sequencing were EF-1 (5′ ATGGGTAAGGARGACAAGAC 3′) and EF-2 (5′ GGARGTACCAGTSATCATG 3′) for translation elongation factor 1-alpha (tef1-α; O’Donnell et al., 1998), LR-OR (5′ ACCCGCTGAACTTAAGC 3′; Vilgalys and Sun, 1994), LR-7 (5′ TACTACCACCAAGATCT 3′; Vilgalys and Hester, 1990) for 28S large subunit of the nrDNA (LSU), and fRPB2-5f (5′ GAYGAYMGWGATCAYTTYGG 3′) and fRPB2-7cR (5′ CCCATRGCTTGYTTRCCCAT 3′) for RNA polymerase second largest subunit (rpb2; Liu et al., 1999).

PCR was carried out in a 25 μL reaction using 12.5 μL 2x Invitrogen Platinum SuperFi PCR Mastermix, 2 μL template DNA (10–20 ng), 1.5 μL 10 pmol primer, 5 μL 5x GC enhancer, and H₂O (Sterile Ultra-Pure Water, Sigma, St. Louis, MO, United States), with the total volume made to 25 μL. The conditions of the thermocycling involved those as follows: For tef1-α gene region, an initial denaturation of 5 min at 94°C, 30 cycles of 45 s at 94°C, 30 s at 57°C, and 1 min at 72°C followed by a final 7-min extension at 72°C; 5 min denaturation at 94°C, 35 cycles of 1 min at 94°C, 50 s at 52°C, and 1.2 min at 72°C, with a final 8 min extension at 72°C for LSU; and 5 min denaturation at 95°C, 35 cycles of 45 s at 95°C, 1 min at 52°C, and 1.5 min at 72°C, with a final 10 min extension at 72°C for rpb2.

The PCR amplicons were purified with a FavorPrep™ PCR purification kit as per the manufacturer’s instructions. Purified PCR products of all marker genes were checked on 1.2% agarose gel electrophoresis stained with 0.5 μg/mL ethidium bromide and were further subjected to a sequencing PCR using a BigDye®Terminator v3.1 Cycle Sequencing Kit, as per the manufacturer’s instructions. In brief, the sequencing PCR of 20 μL included 4 μL of 5× sequencing buffer, 2 μL of BigDye™ Terminator premix, 4 μL of primer (5 pmol), and 4 μL of the purified amplicon and H₂O (Sterile Ultra-Pure Water, Sigma), with the volume made to 20 μL. Thermal cycling conditions consisted of an initial denaturing at 96°C for 3 min, followed by 30 cycles of 94°C for 10 s, 50°C for 40 s, and 60°C for 4 min. The BigDye® terminators and salts were removed using the BigDye Xterminator® Purification Kit (Thermo Fisher Scientific, Waltham, MA, United States) as per the manufacturer’s instructions. After performing cycle sequencing with BigDye™ terminators, 80 μL of SAM™ solution and 20 μL of XTerminator™ solution were added to each tube. The mixture was vortexed for 30 min and then centrifuged at 10,000 rpm for 30 s. The supernatant was transferred to a 96-well microplate, and the module was selected and run was set up. The sequence was elucidated on Applied Biosystems SeqStudio Genetic Analyzer (Applied Biosystems, Foster City, CA, United States). Sequences obtained were submitted in NCBI GenBank [accession numbers OM032811 (tef-1α), OM032812 (rpb2), and OM025235 (LSU)].

To determine the phylogenetic status of this isolate, tef-1α and rpb2 gene regions were used to compare the present isolate with already known authentic strains in the genus Fusarium. The sequences of the related authentic strains were retrieved from NCBI. A total of 83 isolates of the genus Fusarium were used in the phylogenetic analysis and were aligned along with the sequences of Fusarium indicum NFCCI 5145. Geejayessia zealandica CBS 111.93 and Geejayessia cicatricum CBS 125549 were selected as the outgroup taxa. The strains which were used in making phylogenetic tree, along with their accession numbers and other related details, are presented in Supplementary Table 1. Each gene region was aligned individually with MAFFT v. 6.864b (Katoh and Standley, 2013). The alignments were checked and adjusted manually using AliView (Larsson, 2014). Furthermore, alignments were concatenated and processed for the phylogenetic analyses. The best substitution model was figured using ModelFinder (Kalyaanamoorthy et al., 2017). Additionally, Windows version IQ-tree tool v.1.6.11 (Nguyen et al., 2015) was used to reconstruct the phylogenetic tree. The reliability of the tree branches was assessed and tested on the basis of 1,000 ultrafast bootstrap support replicates (UFBoot) and the SH-like approximate likelihood ratio test (SH-like aLRT) with 1,000 replicates. The constructed phylogenetic tree was visualized in FigTree v.1.4.4.

In total, 100 mg of the fungal mass was crushed using a mortar-pestle in liquid N₂. The powder was placed in a 2 mL sterile Eppendorf tube. Overall, 1 mL of pre-heated CTAB buffer [20 mM EDTA, 100 mM Tris HCl, and 1.4 M NaCl and CTAB 2%] was added along with 20 μL of β-mercaptoethanol and 1 mg of polyvinylpyrrolidone (PVP). The mixture was mixed properly and incubated at 65°C ± 2°C for at least 30 min. An equal amount of phenol:chloroform:isoamyl alcohol (25:24:1, v/v) was added and mixed well, and centrifuged at 10,000 rpm for 10 min. The upper aqueous layer was transferred to a fresh 1.5 mL Eppendorf tube and followed by the addition of an equal volume of chloroform:isoamyl alcohol (24:1, v/v) and mixed well and then centrifuged at 10,000 rpm for 10 min. The upper aqueous layer was transferred to a fresh 1.5 mL Eppendorf tube, and an equal volume of isopropanol was added and incubated under cold conditions at −20°C for 20 min. Furthermore, centrifugation was carried out at 10,000 rpm for 10 min at 4°C. The supernatant was removed, and the pellet was carefully washed using 500 μL of 70% ethanol. Again, centrifugation was carried out at 10,000 rpm for 5 min at 4°C. The supernatant was discarded, and the pellet was dried. The pellet was dissolved in 70 μL of 1× TE buffer. In total, 1 μL of RNase A solution (20 mg mL⁻¹) was added and later incubated at 37°C for at least 30 min. The integrity was evaluated by 1% agarose gel electrophoresis, and purity was accessed by a NanoDrop™ 1,000 Spectrophotometer (Thermo Fisher Scientific).

Library construction was done using the QIASeq FX DNA library preparation protocol (Cat#180475) as per the manufacturer’s instructions. In total, 50 ng of Qubit quantified DNA was enzymatically fragmented, end-repaired, and A-tailed in the one-tube reaction using the FX enzyme mix provided in the QIASeq FX DNA kit. The end-repaired and adenylated fragments were subjected to adapter ligation, whereby the index-incorporated Illumina adapter was ligated to generate sequencing libraries. These libraries were subjected to 6 cycles of Indexing PCR [initial denaturation at 98°C for 2 min and cycling (98°C for 20 s, 60°C for 30 s, and 72°C for 30 s) and final extension at 72°C for 1 min] to enrich the adapter-tagged fragments. Finally, for purification of the amplified libraries, JetSeq Beads were used (Bio-68031). Furthermore, quantification of the sequencing library was carried out by a Qubit fluorometer (Thermo Fisher Scientific, MA, United States). The sequencing of the libraries was performed on an Illumina NovaSeq 6000 sequencer (Illumina, San Diego, CA) for 150 bp paired-end chemistry, according to the manufacturer’s procedure.

Libraries were paired-end sequenced using an Illumina NovaSeq 6000 sequencer. After sequencing, the paired-end raw data were kept in FASTQ format. Fastp (0.20.1) tool was used to remove low-quality reads, adapters, and polyG tails from FastQ files.¹ To get the draft genome sequence, St. Petersburg genome assembler SPAdes version 3.11.1 was used for assembly.² The genome diagram of Fusarium indicum NFCCI 5145 was constructed using Circos version 0.69-9 (Krzywinski et al., 2009). Augustus 3.4.0 tool was used for performing gene prediction.³ The gene function and metabolic pathway data available in the already existing databases were used to carry out the function annotation, and BLAST searches were performed against various databases such as NR (NCBI non-redundant protein sequences), Uniprot, COG (Cluster of Orthologous Groups of proteins), KEGG (Kyoto Encyclopedia of Genes and Genomes), CAZy (Carbohydrate-Active Enzymes Database; Lombard et al., 2014), and PHI (Pathogen Host Interactions Database; Urban et al., 2020). Secondary metabolite biosynthetic gene clusters of Fusarium indicum NFCCI 5145 were analyzed using antiSMASH fungal 6.1.1 (Blin et al., 2021). Tandem Repeats Finder Program (trf) version 4.09.1 was used to predict the number of repeats⁴ (Benson, 1999).

Orthologous proteins were identified using OrthoFinder version 2.5.4 (Emms and Kelly, 2019), and the results were used to build a species tree, visualized using FigTree. Fusarium species used for the study of the orthologous proteins and phylogenetic tree construction are presented in Table 1. The analysis of average nucleotide identity (ANI) was performed using the pyani script and ANIb as an algorithm for the alignment (Pritchard et al., 2016). Fusarium species used in the analysis of ANI are presented in Table 2.

Fusarium indicum S. Rana and S.K. Singh, sp. nov. Figures 1A–K, 2.

MycoBank Number: MB 847911

Holotype: AMH 10381

Etymology: Named after the country of isolation “India.”

Host/distribution: As endophyte from Bambusa sp. collected from Panchrukhi, Himachal Pradesh, India.

Original description: Asexual morph Mycelium appeared in parallel bundles of hyphae, simple to branched, septate, smooth-walled, hyaline, thin to thick, showing anastomoses, 1.0–6.5 μm wide (x̄ = 3.58 μm, n = 10). Conidiophores produced from superficial lateral hyphae, simple to branched, gradually decreasing to the length, septate, sometimes rudimentary protruding from superficial hyphae 24.67–118 × 1.35–4.20 μm (x̄ = 59.97 × 2.9 μm, n = 10). Conidiogenous cells are phialidic. Phialides produced directly from superficial hyphae, cylindrical gradually decreasing toward the length, ampuliform, monophialides to polyphialides, sometimes reduced to conidiogenous cell 4.5–43.70 × 2.25–4.90 μm (x̄ = 24.75 × 3.51 μm, n = 10). Microconidia rarely produced, hyaline, smooth-walled, fusoid to cylindrical, straight to curved, 0–1 septate, 9.5–19 × 2.15–4.5 μm (x̄ = 14.18 × 3.15 μm, n = 30). Macroconidia straight to curved, guttulate, short-beaked, 0–3 septate, foot cell prominent, 12.85–46.5 × 2.57–7.5 μm (x̄ = 23.04 × 3.73 μm, n = 30). Chlamydospores are rare, terminal to intercalary, sub-globose to globose, or solitary or in groups of 2–3.

Cultural characteristics: —Colonies growing on PDA reached 39 mm after 4 days at 25°C; yellowish white (1A2) to white (1A1), reverse pale yellow (3A3) after 1 week. In the colony, aerial mycelium is produced, colonies lacking distinct odor, colonies slightly raised, cottony, margin smooth and entire. Colonies growing on SNA reached 33 mm after 4 days of incubation at 25°C; grayish white (1B1) to white (1A1) after 1 week. Colony cottony, raised from the center, and flat toward the periphery with entire smooth margins.

Sexual morph: Not observed.

Known distribution: Panchrukhi, Himachal Pradesh, India.

Material examined: INDIA, Himachal Pradesh, Panchrukhi (32°03′01.1″N 76°34′01.8″E), from leaves of Bambusa sp., S. rana, 4 October 2021, AMH 10381(holotype), deposited in Ajrekar Mycological Herbarium (AMH) of India, ex-type culture is deposited in National Fungal Culture Collection of India (NFCCI 5145).

GenBank numbers: OM032811 (tef-1α), OM032812 (rpb2), and OM025235 (LSU).

Notes: The present species is somewhat similar to F. concolor morphologically (Reinking, 1934; Booth, 1971) in having pale pigmentation and marked heel on the foot cell of macroconidia. It is different from other taxa in the complex. The colonies of F. anguioides are carmine to ochre aerial mycelia, having red to brick tinges of pigmentation; Fusarium austroafricanum produces white to reddish white (7A2) colonies on PDA and reverse is light orange (6A4), while F. indicum produces white to yellowish white colonies on PDA. F. concolor differs from F. indicum in having smaller phialides compared with that of F. indicum and sometimes reduced to conidiogenous cell; aerial phialides monophialidic in F. bambusarum and polyphialidic in F. concolor vs. monophialidic to polyphialidic F. indicum. Macroconidia in F. concolor are usually 3–5 septate and occasionally 6–7 septate, F. austroafricanum macroconidia are 0–11 septate but mostly 3–8-septate, F. anguioides macroconidia 4–7 septate; F. bambusarum macroconidia 3–6 septate; however, F. indicum macroconidia are 0–3 septate (Booth, 1971; Jacobs-Venter et al., 2018; Yli-Mattila et al., 2018; Wang et al., 2022).

Fusarium concolor species are reported predominantly from soil; F. anguioides species have been reported from bamboo, Cordyline stricta and Alocasia odora; Fusarium austroafricanum was isolated as endophyte from Pennisetum clandestinum (kikuyu grass); Fusarium bambusarum species have been reported from bamboo (Booth, 1971; Nelson et al., 1995; Jacobs-Venter et al., 2018; Wang et al., 2022). Though F. anguioides, F. bambusarum, and F. indicum share the same host, they are quite distinct morphologically as well as based on the molecular data.

On the basis of MegaBLAST algorithm search on NCBI blastn⁵ for Fusarium indicum NFCCI 5145, the closest hit using tef-1α gene sequence was found to be Fusarium concolor (NRRL 13994, type) showing 92.59% (638 out of 689 bp) identity and having 15 gaps (2.17%) and with Fusarium austroafricanum (NRRL 66741, type) showing 93.48% (617 out of 660 bp) identity and having 4 gaps (0.6%); based on rpb2, closest hits were Fusarium concolor (NRRL 13994, type) showing 94.21% (766 out of 813 bp) identity and having 2 gaps (0.2%) and with Fusarium austroafricanum (NRRL 53441) showing 93.74% (644 out of 687 bp) identity and having 4 gaps (0.58%).

Additionally, the tef-1α gene sequence of Fusarium indicum NFCCI 5145 showed 93.54% (623 out of 666 bp) identity and had 6 gaps when compared with Fusarium bambusarum LC7180, and with Fusarium anguioides LC13612 showed 89.90% (595 out of 667 bp) identity and 10 gaps (1%; 10 out of 667 bp). Additionally, the rpb2 gene sequence of Fusarium indicum NFCCI 5145 showed 93.63% (735 out of 785 bp) identity when compared with Fusarium bambusarum LC7180 and with Fusarium anguioides LC13612 showed 91.84% (721 out of 785 bp) identity.

The sequence alignments of both tef-1α and rpb2 were used to confirm the identity of this isolate. The concatenated file had sequence data of 86 taxa (Supplementary Table 1). Alignment contained 1,671 columns, 777 parsimony-informative, 1,061 distinct patterns, 113 singleton sites, and 781 constant sites. TIM2e + I + G4 was considered to be the best model and was selected based on the Bayesian Information Criterion (BIC). The phylogenetic tree was generated using the maximum likelihood method based on the above-mentioned model. The log-likelihood of the consensus tree was −24373.628. Rate parameters were A–C: 1.95361, A–G: 4.81458, A–T: 1.95361, C–G: 1.00000, C–T: 9.32964, and G–T: 1.00000; base frequencies were A: 0.250, C: 0.250, G: 0.250, and T: 0.250, and the proportion of invariable sites was 0.387 and gamma shape alpha parameter was 1.138. Combined phylogenetic analysis using tef-1α and rpb2 nested this isolate, Fusarium indicum, in a distinct and unique clade in the Fusarium concolor species complex. The clade was well supported with strong SH-like aLRT and ultrafast bootstrap (UFBoot; Figure 2).

The genome sequence of Fusarium indicum NFCCI 5145 was assembled and deposited in the NCBI GenBank database (SRA accession No. PRJNA993417; BioProject PRJNA993417; BioSample SAMN36633317; accession number JAWDHB000000000). The genome diagram of Fusarium indicum NFCCI 5145 shows that there are nine circles in the circle diagram (Figure 3), which are as follows from inside to outside: the first blue line shows in-paralog regions; the second circle shows the GC skew, with the green part showing a positive GC SKEW and the orange part showing a negative GC SKEW; the third circle shows the GC content (%; negative gene; positive gene); the fourth circle shows secondary metabolites; the fifth circle shows ncRNA; the sixth circle shows repeats; the seventh circle and the eighth circle display CDS annotation information. The seventh circle indicates that CDS is in a positive chain, and the eighth circle indicates that CDS is in a negative chain. The outer rim shows the contigs.

The whole genome size of Fusarium indicum NFCCI 5145 was 40.2 Mb. This consisted of 513 scaffolds with an N50 of 0.46 Mb and 48.39% of GC content. A total of 7,884,552 raw reads and 7,847,766 clean and high-quality reads (99.53%) were generated in the Illumina sequencing. Before filtering, total reads were 7.884552 M, total bases were 1.182683 G, Q20 bases were 1.162804 G (98.319170%), Q30 bases were 1.121368 G (94.815622%), and GC content was 48.005470%. After filtering, total reads were 7.847766 M, total bases were 1.176427 G, Q20 bases were 1.158196 G (98.450277%), Q30 bases were 1.117366 G (94.979678%), and GC content was 48.000585%. Reads that passed the filters were 7.847766 M (99.533442%), reads with low quality were 33.424000 K (0.423918%), reads with too many N were 2.328000 K (0.029526%), and reads which were too short were 1.034000 K (0.013114%). The total number of scaffolds was 513, the total number of bases (bp) were 40,226,774 (~40.2 Mb), the minimum scaffold length (bp) was 300, the maximum scaffold length (bp) was 1,668,425, scaffolds ≥ 200 kbp were 513, scaffolds ≥ 500 kbp were 347, scaffolds ≥ 1 kbp were 246, scaffolds ≥ 10 kbp were 169, scaffolds ≥ 1 Mbp were 6, and N50 value was 461,173. The Augustus prediction method was used to predict the encoding gene. In total, 12,724 protein-coding genes were predicted using highly annotated databases such as Uniprot. Gene total length (bp) was 6,336,400, gene average length (bp) was 498, maximum gene length (bp) was 8,599, and minimum gene length (bp) was 24. Simultaneously, the Tandem Repeats Finder Program (trf) was found to predict the number of repeats, which were found to be 3,232.

For the prediction of the protein sequences, 12,963 non-redundant genes of Fusarium indicum NFCCI 5145 were subjected to a similarity search on the basis of various public databases. Many genes were mapped using the Uniprot database (12,638 genes/97.49%), Clusters of Orthologous Groups (COG; 6,509 genes/50.21%), and Kyoto Encyclopedia of Genes and Genomes (KEGG; 9,155 genes/70.62%).

As per COG database, “General function prediction only” was related with many genes (1436), followed by “Carbohydrate transport and metabolism (624),” “Amino acid transport and metabolism (489),” “Function unknown (422),” “Post Translational modification, protein turnover, chaperones (405),” and “Translation, ribosomal structure and biogenesis (401)” (Figure 4; Natale et al., 2000). These results depict that Fusarium indicum NFCCI 5145 possesses a varied and enriched array of functions for carbohydrates and amino acid metabolism that may result in better energy conversion efficiency.

The findings from KEGG functional classification suggest that the predicted proteins fell under various categories, such as amino acid metabolism (2451), metabolism of cofactors and vitamins (1682), global map (1526), and carbohydrate metabolism (1525; Figure 5; Yamada et al., 2021). The results indicate that there is a varied and enriched array of various metabolic functions present that probably will provide higher secondary metabolism efficacy.

GO annotation depicts varied genes possessed by Fusarium indicum, which may be involved in biological processes, cellular components, and molecular functions (Figure 6; Huntley et al., 2014).

Carbohydrate-active enzymes (CAZymes) are classes of enzymes that catalyze the breakdown and assembly of glycoconjugates as well as glycans (oligosaccharides and polysaccharides; Garron and Henrissat, 2019). These enzymes play an important role in fungal metabolism as they are accountable for carbohydrate degradation and modification as well as biosynthesis (Liu et al., 2022). The CAZy is a specialized database for carbohydrate enzymes that have the capability to create, modify, and degrade glycosidic bonds (Liu et al., 2022). The analysis showed 1,012 genes that encode for carbohydrate-active enzymes (CAZy) dispersed in the genome of Fusarium indicum NFCCI 5145. These include 109 auxiliary activities (AAs), 115 carbohydrate-binding modules (CBMs), 64 carbohydrate esterases (CEs), 458 glycoside hydrolases (GHs), 238 glycosyltransferases (GTs), and 28 polysaccharide lyases (PLs; Figure 7). AAs mainly included AA1-16 16 families. CBMs distributed mainly across 23 families, including CBM1–2, CBM5–6, CBM9, CBM12–14, CBM18, CBM20–21, CBM24, CBM32, CBM35, CBM38, CBM41–43, CBM48, CBM50, CBM63, CBM67, and CBM87. Carbohydrate esterases were classified as CE1–5, CE8–9 CE12, CE14, and CE16 across 10 families. Glycoside hydrolases were distributed across 76 families, including GH1–3, GH5, GH7, GH9–13, GH15–18, GH20, GH23–33, GH35–39, GH43, GH47, GH49, GH51, GH53, GH55, GH62–65, GH67, GH71–79, GH81, GH86, GH88, GH92–95, GH103, GH105, GH114–115, GH123, GH125, GH128, GH130–132, GH135–136, GH139, GH141, GH146, GH152, GH154, and GH162. GTs contained 43 families, including GT1–4, GT8, GT10, GT11, GT15, GT17–18, GT20–24, GT28, GT30–35, GT39, GT41, GT43, GT47–48, GT50–51, GT57–59, GT61–62, GT64, GT66, GT69, GT71, GT76, GT90, GT106, GT107, and GT109. PLs are mainly distributed in eight families, including PL1, PL4, PL3, PL9, PL22, PL26, PL35 and PL42. These findings show that Fusarium indicum NFCCI 5145 can prove to show great ability to make and break complex carbohydrates making it capable of capturing more energy, thus possibly having great industrial applicability.

The Pathogen Host Interactions Database (PHI-base) is a database that is manually curated by experts based on experimental evidence that consists of genes related to virulence, effector, and pathogenicity from fungi, bacteria, and oomycete that infect plants, animals, insects, and fungi (Urban et al., 2022). The amino acid sequence of Fusarium indicum NFCCI 5145 was compared with the PHI database. As shown in Figure 8, Fusarium indicum NFCCI 5145 possesses abundant PHI-base genes, including reduced virulence (853), increased virulence (hypervirulence; 66), loss of pathogenicity (154), lethal (99), unaffected pathogenicity (867), sensitivity to chemical (2), effector (plant avirulence determinant; 21), and resistance to chemical (6; Pernas, 2021). Unaffected pathogenicity and reduced virulence were the major annotation genes, indicating that Fusarium indicum NFCCI 5145 is not a pathogenic strain as expected as it was isolated as an endophyte.

AntiSMASH results indicated that Fusarium indicum isolate NFCCI 5145 contains 45 secondary metabolite biosynthetic gene clusters (BGCs), including eight NRPS-like fragments (NRPS-like), nine nonribosomal peptide synthetases (NRPSs), six terpene synthases, 12 Type I PKS (polyketide synthase; T1PKS), one Type III PKS (polyketide synthase; T3PKS), one beta-lactone containing protease inhibitor (betalactone), three hybrid NRPS + T1PKS, two indoles, one hybrid indole + NRPS, one hybrid T1PKS and NRPS, and one hybrid NRPS, T1PKS and indole (Table 3; Figure 9A–N).

AntiSMASH results revealed the potential of this isolate to produce interesting compounds, such as α-acorenol, oxyjavanicin, chrysogine, equisetin, bikaverin, squalestatin S1, and many other known and unknown secondary metabolites. α-Acorenol is a highly oxygenated sesquiterpene that has antioxidant activity (Elshamy et al., 2019). Oxyjavanicin belongs to the naphthoquinone class of compounds and is similar to Fusarubin (C₁₅H₁₄O₇), a red antibiotic (Ruelius and Gauhe, 1950). Many studies have reported its antituberculosis, cytotoxic, and antimicrobial activities; it can be a beneficial drug for the treatment of asthma as it regulates cytokine balance in OVA-sensitized (Hong et al., 2022). Fusarubin is also known to inhibit proliferation and also increase apoptosis in cell lines derived from hematological cancers (Adorisio et al., 2019). Chrysogine is a yellow pigment known to lack antimicrobial or anticancer activity (Viggiano et al., 2018). Equisetin is more known for its antibiotic and cytotoxic activity; it also inhibits HIV-1 integrase. It can also potentiate antibiotic activity against multi-drug-resistant gram-negative bacteria (Zhang et al., 2021). It is known to inhibit bacterial acetyl-CoA carboxylase (ACC), which is the first step of fatty acid synthesis (Larson et al., 2020). Bikaverin belongs to the polyketide class of compounds and is a reddish pigment having many biological properties including antitumoral activity against different cancer cell lines (Limón et al., 2010). Squalestatin S1 is a potent inhibitor of squalene synthase with potential use in the control of cholesterol biosynthesis (Lebe and Cox, 2018). The functions associated with other cryptic BGCs can be characterized with the help of gene knockout and heterogeneous expression experiments, along with the help of LC-MS analysis.