Characterization of the Black Shank Pathogen, Phytophthora nicotianae, Across North Carolina Tobacco Production Areas

Quasi-targeted metabolomics revealed isoliquiritigenin and lauric acid associated with resistance to tobacco black shank

Tobacco black shank (TBS), caused by Phytophthora nicotianae, is a severe disease. Plant root exudates play a crucial role in mediating plant-pathogen interactions in the rhizosphere. However, the specific interaction between key secondary metabolites present in root exudates and the mechanisms of disease resistance remains poorly understood. This study conducted a comprehensive comparison via quasi-targeted metabolomic analysis on the root exudate metabolites from the tobacco cultivar Yunyan87 and K326, both before and after inoculation with P. nicotianae. The results showed that the root exudate metabolites changed after P. nicotianae inoculation, and the root exudate metabolites of different tobacco cultivar was significantly different. Furthermore, homovanillic acid, lauric acid, and isoliquiritigenin were identified as potential key compounds for TBS resistance based on their impact on the mycelium growth of the pathogens. The pot experiment showed that isoliquiritigenin reduced the incidence by 55.2%, while lauric acid reduced it by 45.8%. This suggests that isoliquiritigenin and lauric acid have potential applications in the management of TBS. In summary, this study revealed the possible resistance mechanisms of differential metabolites in resistance of commercial tobacco cultivar, and for the first time discovered the inhibitory effects of isoliquiritigenin and homovanillic acid on P. nictianae, and attempt to use plants secondary metabolites of for plant protection.

Sensitivity of Phytophthora nicotianae in Tennessee and North Carolina to Mefenoxam, Oxathiapiprolin, Mandipropamid, and Fluopicolide

Phytophthora nicotianae causes devastating disease in a range of hosts, including tobacco (N. tabacum L.), tomato, citrus, strawberry, and numerous ornamentals. Black shank, caused by P. nicotianae, is the most economically important disease to tobacco production in Tennessee and North Carolina. Black shank management includes the use of resistant cultivars, crop rotation, and fungicides. Fungicide resistance is a concern for black shank management due to the limited number of active ingredients available and the repeated exposure of pathogen populations to these products. In vitro fungicide sensitivity assays were conducted on 155 P. nicotianae isolates collected in Tennessee and North Carolina in 2021 and 2022 to determine their EC50 values for oxathiapiprolin, mandipropamid, and fluopicolide. The P. nicotianae was isolated predominantly from burley, dark, and flue-cured tobacco showing symptoms of black shank as well as tomato with buckeye rot symptoms. A discriminatory dose was used to determine each isolate's sensitivity to mefenoxam in 2021 and 2022. In 2021, EC50 values were determined for oxathiapiprolin, mandipropamid, and fluopicolide. In 2022, discriminatory doses based on EC75 values were used to determine each isolate's sensitivity to these fungicides. All isolates from the 2 years were sensitive to mefenoxam, mandipropamid, and fluopicolide. One isolate in 2022 was moderately sensitive to oxathiapiprolin, while all other isolates were sensitive.

Characteristics of fluopicolide-resistance mutants in Phytophthora nicotianae, the pathogen causing black shank disease in tobacco

Black shank, a devastating disease in tobacco production worldwide, is caused by the oomycete plant pathogen Phytophthora nicotianae. Fluopicolide is a pyridinylmethyl-benzamides fungicide with a unique mechanism of action and has been widely used for controlling a variety of oomycetes such as Plasmopara viticola, Phytophthora infestans, Pseudoperonospora cubensis, P. nicotianae and Bremia lactucae. However, the fluopicolide-resistance risk and molecular basis in P. nicotianae have not been reported. In this study, the sensitivity profile of 141 P. nicotianae strains to fluopicolide was determined, with a mean median effective concentration (EC50) value of 0.12 ± 0.06μg/mL. Five stable fluopicolide-resistant mutants of P. nicotianae were obtained by fungicide adaptation, and the compound fitness index of these resistant mutants were lower than that of their parental isolates. Additionally, cross-resistance tests indicated that the sensitivity of fluopicolide did not correlate with other oomycete fungicides, apart from fluopimomide. DNA sequencing revealed two point mutations, G765E and N769Y, in the PpVHA-a protein in the fluopicolide-resistant mutants. Transformation and expression of PpVHA-a genes carrying G765E and N769Y in the sensitive wild-type isolate confirmed that it was responsible for fluopicolide resistance. These results suggest that P. nicotianae has a low to medium resistance risk to fluopicolide in laboratory and that point mutations, G765E and N769Y, in PpVHA-a are associated with the observed fluopicolide resistance.

Distinct microbiota assembly and functional patterns in disease-resistant and susceptible varieties of tobacco

The plant microbiota is believed to be an accessory genome that extends plant functions, forming holobionts together with the host plant. Plant disease resistance, therefore, is inextricably linked with plant microbiota, which play important roles in plant growth and health. To explore the relationship between plant microbiota and disease resistance, we investigated the tobacco microbiome of two varieties with contrasting disease-resistance levels to bacterial wilt and black shank diseases. Comparative microbiome analysis indicated that the resistant variety assembled a distinct microbiota with higher network complexity and diversity. While Pseudomonas and Ensifer, which contain biocontrol and beneficial members, were enriched in the rhizosphere of the resistant variety, Ralstonia, a genus including the known causative pathogen, was enriched in the susceptible variety. Metagenome sequencing revealed that biocontrol functions, such as hydrogen cyanide synthase, pyochelin biosynthesis, and arthrofactin-type cyclic lipopeptide synthetase, were more abundant in the resistant variety. Further analysis indicated that contigs encoding the corresponding genes were mostly assigned to Pseudomonas. Among all the metagenome-assembled genomes, positive selection was suggested in the genome assigned to Pseudomonas only in the rhizosphere of the resistant variety. The search of biosynthetic gene clusters in the Pseudomonas genome revealed a non-ribosomal peptide synthetase, the compound of which was brabantamide A, with known antimicrobial activity. Collectively, our study suggests that the plant microbiota might be involved in microbe-mediated disease resistance. Particularly, our results highlight Pseudomonas in the rhizosphere of the disease-resistant variety as a promising biocontrol candidate. Our study may facilitate further screening of bacterial isolates and the targeted design of microbial communities.

Complete genome sequence of Bacillus cereus Z4, a biocontrol agent against tobacco black shank, isolated from the Western Pacific Ocean

Bacillus species have been considered as promising biological control agents due to their excellent antimicrobial ability. Bacillus cereus strain Z4 was isolated from 2000 m deep sea sediments of the Western Pacific Ocean, which possesses significant antifungal activity against Phytophthora nicotianae, the pathogenic fungus of tobacco black shank disease. To reveal the underlying antifungal genetic mechanisms, here, we report the complete genomic sequence of the strain Z4. The genome has one circular chromosome of 5,664,309 bp with a G + C content of 35.31%, 109 tRNAs, and 43 rRNAs. Genomic analysis identified 10 gene clusters related to the biosynthesis of biocontrol active compounds, including bacillibactin, petrobactin, fengycin, and molybdenum cofactor. Meanwhile, 6 gene clusters were responsible for the biosynthesis of metabolites with unknown functions. Strain Z4 also contains a large number of genes encoding carbohydrate-active enzymes and secreted proteins, respectively. The whole genomic analysis of Bacillus cereus Z4 may provide a valuable reference for elucidating its biocontrol mechanism against tobacco black shank.

Understanding the Genotypic and Phenotypic Structure and Impact of Climate on Phytophthora nicotianae Outbreaks on Potato and Tomato in the Eastern United States

Samples from potato fields with lesions with late blight-like symptoms were collected from eastern North Carolina in 2017 and the causal agent was identified as Phytophthora nicotianae. We have identified P. nicotianae in potato and tomato samples from North Carolina, Virginia, Maryland, Pennsylvania, and New York. Ninety-two field samples were collected from 46 fields and characterized for mefenoxam sensitivity, mating type, and simple sequence repeat genotype using microsatellites. Thirty-two percent of the isolates were the A1 mating type, while 53% were the A2 mating type. In six cases, both A1 and A2 mating types were detected in the same field in the same year. All isolates tested were sensitive to mefenoxam. Two genetic groups were discerned based on STRUCTURE analysis: one included samples from North Carolina and Maryland, and one included samples from all five states. The data suggest two different sources of inoculum from the field sites sampled. Multiple haplotypes within a field and the detection of both mating types in close proximity suggests that P. nicotianae may be reproducing sexually in North Carolina. There was a decrease in the average number of days with weather suitable for late blight, from 2012 to 2016 and 2017 to 2021 in all of the North Carolina counties where P. nicotianae was reported. P. nicotianae is more thermotolerant than P. infestans and grows at higher temperatures (25 to 35°C) than P. infestans (18 to 22°C). Late blight outbreaks have decreased in recent years and first reports of disease are later, suggesting that the thermotolerant P. nicotianae may cause more disease as temperatures rise due to climate change.

Naringenin confers defence against Phytophthora nicotianae through antimicrobial activity and induction of pathogen resistance in tobacco

Tobacco black shank caused by Phytophthora nicotianae is a serious disease in tobacco cultivation. We found that naringenin is a key factor that causes different sensitivity to P. nicotianae between resistant and susceptible tobacco. The level of basal flavonoids in resistant tobacco was distinct from that in susceptible tobacco. Of all flavonoids with different content, naringenin showed the best antimicrobial activity against mycelial growth and sporangia production of P. nicotianae in vitro. However, naringenin showed very low or no antimicrobial activity to other plant pathogens. We found that naringenin induced not only the accumulation of reactive oxygen species, but also the expression of salicylic acid biosynthesis-related genes. Naringenin induced the expression of the basal pathogen resistance gene PR1 and the SAR8.2 gene that contributes to plant resistance to P. nicotianae. We then interfered with the expression of the chalcone synthase (NtCHS) gene, the key gene of the naringenin synthesis pathway, to inhibit naringenin biosynthesis. NtCHS-RNAi rendered tobacco highly sensitive to P. nicotianae, but there was no change in susceptibility to another plant pathogen, Ralstonia solanacearum. Finally, exogenous application of naringenin on susceptible tobacco enhanced resistance to P. nicotianae and naringenin was very stable in this environment. Our findings revealed that naringenin plays a core role in the defence against P. nicotianae and expanded the possibilities for the application of plant secondary metabolites in the control of P. nicotianae.

Transcriptomics and iTRAQ-proteomics analyses provide novel insights into the defense mechanism of black shank disease in tobacco

Black shank disease caused by Phytophthora nicotianae is one of the most important diseases in tobacco worldwide and can result in a devastating loss in tobacco cultivation. Many efforts have been carried out to identify the chromosome segment from Nicotiana plumbaginifolia containing a resistance locus carrying a gene named Php; however, the Php gene has not been cloned, and knowledge of the potential mechanism of the Php gene in the resistant lines is limited. To further characterize the resistance mechanism of the Php gene, we first used the resistant line "RBST" and the susceptible cultivar "Honghuadajinyuan" (HD) to obtain the near-isogenic line RBS89 containing the Php gene from RBST. RBS89 showed high resistance to black shank disease. Transcriptomic and iTRAQ analyses were applied to explore the potential defense mechanisms in RBS89 plants in comparison with HD plants with or without inoculation. Many differentially expressed genes (DEGs) and proteins were identified, and some pathogenesis-related (PR) proteins were extensively abundant in the RBS89 plants when compared with the HD plants in response to black shank disease. Importantly, overexpression of the PR gene NtPR-1B in HD plants improved the resistance of tobacco plants to black shank disease, indicating that NtPR-1B and Php genes might have similar roles in protecting tobacco from black shank disease. However, the relationship between NtPR-1B and Php genes requires further analysis. Therefore, our study provides valuable information for breeding tobacco cultivars with black shank disease resistance and sheds light on the defense mechanism of black shank disease in tobacco for enhancing Phytophthora resistance in other Solanaceae crops.

Unraveling the expression of differentially expressed proteins and enzymatic activity in response to Phytophthora nicotianae across different flue-cured tobacco cultivars

BACKGROUND

Black shank disease caused by Phytophthora nicotianae is a serious threat to flue-cured tobacco production. Whole-plant resistance is characterized by the expression of a number of pathogenesis-related proteins, genes, and the activity of different defense-related enzymes. In this study, we investigated the activity of defense-related enzymes and expression of differentially expressed proteins through the iTRAQ technique across two flue-cured tobacco cultivars, i.e., K326 and Hongda, in response to the black shank pathogen.

RESULTS

Results showed that the highest disease incidence was recorded in flue-cured tobacco cultivar Hongda compared with K326, which shows that Hongda is more susceptible to P. nicotianae than K326. A total of 4274 differentially expressed proteins were detected at 0 h and after 24 h, 72 h of post-inoculation with P. nicotianae. We found that 17 proteins induced after inoculation with P. nicotianae, including pathogenesis (5), photosynthesis (3), oxidative phosphorylation (6), tricarboxylic acid cycle (1), heat shock (1), and 14-3-3 (1) and were involved in the resistance of flue-cured tobacco against black shank disease. The expression of 5 pathogenesis-related proteins and the activities of defense-related enzymes (PPO, POD, SOD, and MDA) were significantly higher in the leaves of K326 than Hongda after inoculation with P. nicotianae.

CONCLUSION

These results provide new molecular insights into flue-cured tobacco responses to P. nicotianae. It is concluded that differences in protein expressions and defense-related enzymes play an important role in developing resistance in flue-cured tobacco cultivars against black shank disease.

Adaptation of Phytophthora nicotianae to Multiple Sources of Partial Resistance in Tobacco

Host resistance is an important tool in the management of black shank disease of tobacco. Race development leads to rapid loss of single-gene resistance, but the adaptation by Phytophthora nicotianae to sources of partial resistance from Beinhart 1000, Florida 301, and the Wz gene region introgressed from Nicotiana rustica is poorly characterized. In greenhouse environments, host genotypes with quantitative trait loci (QTLs) conferring resistance from multiple sources were initially inoculated with an aggressive isolate of race 0 or race 1 of P. nicotianae. The most aggressive isolate was selected after each of six host generations to inoculate the next generation of plants. The race 0 isolate demonstrated a continuous gradual increase in disease severity and percentage root rot on all sources of resistance except the genotype K 326 Wz/-, where a large increase in both was observed between generations 2 and 3. Adaptation by the race 0 isolate on Beinhart 1000 represents the first report of adaptation to this genotype by P. nicotianae. The race 1 isolate did not exhibit significant increases in aggressiveness over generations but exhibited a large increase in aggressiveness on K 326 Wz/- between generations 3 and 4. Molecular characterization of isolates recovered during selection was completed via double digest restriction-site associated DNA sequencing, but no polymorphisms were associated with the observed changes in aggressiveness. The rapid adaptation to Wz resistance and the gradual adaptation to other QTLs highlights the need to study the nature of Wz resistance and to conduct field studies on the efficacy of resistance gene rotation for disease management.

Impacts of Continued Exposure to a Susceptible Host Genotype on Aggressiveness of Phytophthora nicotianae Isolates Adapted to Multiple Sources of Partial Resistance

Pathogen adaptation can threaten the durability of partial resistance. Mixed plantings of susceptible and partially resistant varieties may prolong the effectiveness of partial resistance, but little is known about how continued exposure to a susceptible genotype can change the aggressiveness of pathogen isolates adapted to a source of partial resistance. The objective of this study was to examine the effects of continued exposure to a highly susceptible tobacco genotype on isolates of Phytophthora nicotianae that had been adapted to partial resistance. Isolates of P. nicotianae previously adapted to two sources of partial resistance were continually exposed to either the original host of adaptation or a susceptible host. After six generations of host exposure, isolates obtained from the partially resistant and the susceptible hosts were compared for their aggressiveness on the resistant host and for differences in expression of genes associated with pathogenicity and aggressiveness. Results suggested that exposure to the susceptible tobacco genotype reduced aggressiveness of isolates adapted to partial resistance in K 326 Wz/- but not of isolates adapted to partial resistance in Fla 301. Quantification of pathogenicity-associated gene expression using qRT-PCR suggested the rapid change in aggressiveness of isolates adapted to Wz-sourced partial resistance may have resulted from modification in gene expression in multiple genes.

Components of Aggressiveness in Phytophthora nicotianae During Adaptation to Multiple Sources of Partial Resistance in Tobacco

Black shank is a devastating disease of tobacco caused by Phytophthora nicotianae. Host resistance has been an integral part of black shank management but after the loss of Php single-gene resistance following its widespread deployment in the 1990s, growers have relied on varieties with varying levels of partial resistance. Partial resistance is effective in suppressing disease, but continued exposure can result in an increase in pathogen aggressiveness that threatens durability of the resistance to P. nicotianae. Aggressiveness components in P. nicotianae were characterized following adaptation on two sources of partial resistance, Fla 301 and the Wz genomic region from Nicotiana rustica. An aggressive isolate of the two major races of P. nicotianae, race 0 and race 1, was adapted for either one/two or five/six generations on the two resistance sources, giving four sets of isolates based on race, number of generations of adaptation, and source of resistance. Across the four sets of isolates, adapted isolates infected higher proportions of tobacco root tips, produced more sporangia per infected root tip, and caused larger lesions than their respective nonadapted isolates of the same race and from the same resistance source. Adapted isolates also produced more aggressive zoospore progeny than the nonadapted isolates. Adaptation to partial resistance involves multiple aggressiveness components and results in the increased aggressiveness observed for P. nicotianae. These results improve our knowledge on the nature of P. nicotianae adaptation to partial resistance in tobacco and indicate that different resistance sources are likely to select for similar aggressiveness components in the pathogen.

First Report of Eggplant Fruit Rot Caused by Phytophthora nicotianae Breda de Haan in Mexico

Eggplant (Solanum melongena L.) is an important solanaceous crop that is produced mainly in tropical and subtropical regions and is widely consumed worldwide. In 2018, eggplant production in Mexico was approximately 80000 t, and Sinaloa State contributed 96% of this production; however, this crop suffers significant losses from plant pathogens. In December 2019, fruits from commercial orchards (geographical coordinates: 24°45'39.39''N, 107°26'57.30''O) with visible brown soft rot and profuse white mycelia were analysed. On V8 medium, pieces of tissue obtained from the border of lesions were plated and incubated between 25°C and 36°C. After five days, a dense cottony mycelium with a slightly petaloid pattern was observed at 25°C and did not grow at 36°C. Isolates of that pathogen were heterothallic, and microscopic preparations showed development of coenocytic mycelium and spheroid sporangia that were noncaducous and papillate, measuring 35.6 ± 5.8 x 27.1 ± 4.4. Based on morphological characteristics, the eggplant soft rot causal agent was identified as Phytophthora nicotianae Breda de Haan (Erwin and Ribeiro, 1996). From a representative isolate denominated PhySm01, two DNA regions (internal transcribed spacer (ITS) and the large subunit ribosomal (28S)) were amplified and sequenced with ITS1-ITS4 and NL1-LR3 primers, respectively. The obtained ITS sequence (GenBank accession number MT508842) showed 100% identity with several P. nicotianae sequences (Access MT065840, MH290435 and MG570057) with 100% query coverage and 740 matching nucleotides. For the 28S sequence (accession number MT508843), the identity with strains N° Access EU080889 and EU080508 of P. nicotianae was 99.86%, with 100 query coverage and 729 matching nucleotides. Further, phylogenetic analysis from P. nicotianae strain PhySm01 and GenBank reference sequences was carried out by Maximum Likelihood method with Mega 7 software based on the ITS sequences, which verified the species identification. To fulfill Koch's postulates, a suspension containing 1 x 104 zoospores/mL of the oomycete isolated from the original diseased eggplant fruit was used to inoculate ten healthy and disinfested fruits. Sterile water was used as a control. Three wounds per fruit were made with a sterile needle, and 20 μL of the zoospore suspension (or water) was placed on each. All fruits were placed into plastic bags with moistened paper and incubated at 25°C for three days. Thisest was repeated twice with similar results. Initial symptoms developed 24 hours after inoculation with brown soft tissue forming around the inoculated area, and profuse soft rot accompanied by white mycelium was observed two days after inoculation. No symptoms developed on the control fruits during this time. Pieces of necrotic tissue were plated on V8 medium and incubated as described previously. The reisolated pathogen was compared to the original isolate and had the same morphological characteristics. Phytophthora nicotianae has a worldwide distribution and can infect multiple solanaceous crops, including tobacco (Gallup et al., 2018). In addition, it has been reported on other hosts outside of the Solanaceae family, causing economically important losses in citrus and strawberry. In India, it causes necrosis of citrus fruits and roots, leading to tree decline (Das et al., 2016), and in the United States, it causes crown rot of strawberry (Marin et al., 2018). In Mexico, P. nicotianae has been reported on vinca (Alvarez-Rodriguez et al., 2013); however, this is the first report of P. nicotianae causing fruit soft rot of eggplant, and this pathogen represents a new threat when the environment is favourable for disease outbreaks. References Alvarez-Rodriguez, B. et al. 2013. Plant Dis. 97: 1257. https://doi.org/10.1094/PDIS-04-13-0400-PDN Das, A. K. et al. 2016. J. Plant Pathol. 98: 55. DOI: 10.4454/JPP.V98I1.038 Erwin, D. C. and Ribeiro, O. K. 1996. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN. 562 Pp. Gallup, C. A. et al. 2018. Plan Dis. 102: 1108. https://doi.org/10.1094/PDIS-02-17-0295-RE Marin, M. V. et al. 2018. Plant Dis. 102:1463. https://doi.org/10.1094/PDIS-08-17-1333-PDN.

Effects of manganese and zinc on the growth process of Phytophthora nicotianae and the possible inhibitory mechanisms

Background

Phytophthora nicotianae is a fungal soil-borne pathogen that damages various plant species. Mancozeb and Zineb, fungicides containing manganese (Mn) and zinc (Zn) as the main components, are widely used to control the diseases caused by Phytophthora. However, the inhibition mechanism is still unclear. The purpose of this study was to examine the effects of Mn and Zn on P. nicotianae and to determine possible inhibitory mechanisms of Mn and Zn on sporangiogenesis of P. nicotianae.

Methods

The mycelial growth, sporangium generation, zoosporogenesis and zoospore germination of P. nicotianae were observed under Mn and Zn treatments. The gene (csn4 and csn7) expression levels of P. nicotianae in different growth stages were examined. Csn4 and csn7 gene expression, superoxide dismutase (SOD) activity, catalase (CAT) activity and malondialdehyde (MDA) content were tested at the stage of sporangiogenesis under different Mn and Zn concentrations.

Results

Mycelial growth of P. nicotianae was significantly inhibited by Mn from ≥1 mg/L concentration and by Zn from ≥10 mg/L. The sporangia production, sporangia release, and zoospore germination of P. nicotianae were significantly reduced by Mn at all concentrations, while treatment with Zn from ≥0.5 mg/L concentration significantly inhibited the same processes. At the same concentration, the inhibition rate of Mn on the growth process of P. nicotianae was higher than that of Zn. The csn4 and csn7 gene transcription of P. nicotianae were significantly reduced by all treatments with Mn and Zn at the stage of sporangiogenesis. With the increase of Mn concentration, the activities of SOD and CAT increased to maxima and then decreased, and the content of MDA gradually increased during sporangiogenesis of P. nicotianae. The sporangia production of P. nicotianae was significantly positively correlated with the expression levels of the genes csn4 and csn7.

Conclusion

The inhibitory effect of Mn on the growth process of P. nicotianae was stronger than that of Zn, especially on sporangiogenesis and zoosporogenesis. A possible mechanism of the inhibitory effect on sporangiogenesis of P. nicotianae was that Mn and Zn acted by inhibiting the expression levels of the genes csn4 and csn7 and by affecting antioxidant enzyme activity (further resulting in lipid peroxidation) in the sporangium of P. nicotianae.

Overexpression of SoCYP85A1 Increases the Accumulation of Castasterone and Confers Enhanced Black Shank Tolerance in Tobacco Through Modulation of the Antioxidant Enzymes' Activities

Black shank caused by Phytophthora nicotianae is one of the most devastating diseases in tobacco production. In this study, we characterized a novel cytochromic resistance gene, SoCYP85A1, from spinach, which was upregulated in response to P. nicotianae infection. Overexpression of SoCYP85A1 in tobacco resulted in remarkable resistance to pathogen inoculation, with diverse resistance levels in different transgenic lines. Meanwhile, a significant accumulation of castasterone (CS) was detected in transgenic plants when challenged with the pathogen. Moreover, activities of antioxidant enzymes were enhanced by SoCYP85A1 in the transgenic lines as compared to those in the wild types inoculated with P. nicotianae. In addition, the alteration of CS content resulted in interference of phytohormone homeostasis. Overall, these results demonstrate that SoCYP85A1 can participate in the defense response to P. nicotianae through the involvement of defense enzymes and by interaction with certain phytohormones. Our findings suggest that SoCYP85A1 could be used as a potential candidate gene for improving resistance to black shank disease in tobacco and other economic crops.