BIOTROPIA Vol. 31 No. 1, 2024: 106 - 113 DOI: 10.11598/btb.2024.31.1.2159 106 ENHANCEMENT OF TOMATO GROWTH AND BIOCONTROL OF FUSARIUM SOLANI ROOT ROT DISEASE BY STREPTOMYCES ROCHEI BT02 LÊ THANH ĐẠM, NGUYỄN LƯU VĨNH HẢO, NGUYỄN THỊ HỒNG HẠNH, THẠCH THỊ THẢO, QUẢNG THỊ ANH ĐÀO, PHAN MINH ĐẠT AND NGUYỄN VŨ PHONG* Faculty of Biological Sciences, Nong Lam University, Ho Chi Minh City 72820, Vietnam. Received 1 January 2024/ Revised 26 February 2024/ Accepted 13 March 2024 ABSTRACT This study investigated the dual role of Streptomyces rochei BT02 in promoting tomato growth and suppressing Fusarium solani, the causative agent of tomato root rot disease. Various assays were conducted to evaluate the plant growth-promoting attributes of strain BT02 including indole-3-acetic acid (IAA) biosynthesis, phosphate solubilization, biofilm formation, and siderophore production. Under in vitro conditions, strain BT02 exhibited plant growth-promoting characteristics such as cellulose degradation, phosphate solubilization, IAA synthesis, biofilm formation, and siderophore production. Application of strain BT02 significantly improved tomato seed germination (26.7%), with enhanced sprout and radicle lengths and seed vigor (38.6%). Greenhouse experiments revealed substantial increases in plant height, leaf and branch numbers, inflorescence, and flower number, emphasizing the positive impact of strain BT02 on overall plant growth. The BT02 strain demonstrated antagonistic efficacy of 45.3 to 58.9% against Fusarium solani, as evidenced by the dual culture and agar well diffusion methods. Under greenhouse conditions, strain BT02 significantly reduced disease incidence and demonstrated control efficacy of 41.6% against Fusarium solani, highlighting its biocontrol potential. This study provides insights into the mechanisms employed by Streptomyces rochei BT02 to enhance plant growth and suppress root rot disease, paving the way for its application as a biocontrol agent in sustainable agriculture. Keywords: Fusarium solani biocontrol, plant growth-promoting bacteria (PGPB), root rot disease control, Streptomyces rochei BT02; tomato growth promotion INTRODUCTION With ever-increasing global population growth and the consequential negative environmental impacts, ensuring the quality of agricultural products poses a formidable challenge for both farmers and researchers. The adoption of biofertilizers and biotic agents, together with judicious farming management practices, have attracted significant attention within the scientific community, with the utilization of plant growth-promoting bacteria (PGPB) extensively documented. PGPB are ubiquitously distributed in soil and on root surfaces or endophytically within roots. They exhibit remarkable capabilities of fostering plant growth and curtailing plant diseases through multifaceted mechanisms encompassing direct processes such as phosphorus solubilization, nitrogen fixation, siderophore production, hydrogen cyanide and ammonia release as well as the synthesis of phytohormones including auxin, cytokinin, and gibberellin. Indirect mechanisms include ACC deaminase activity, antibiotic production, secretion of cell wall degradation enzymes, and induction of systemic resistance (Ryu et al. 2003). Among plant growth-promoting rhizobacteria (PGPR), Streptomyces species are widely distributed in soil, water, and agricultural ecosystems. This diversity in nutritional and physiological processes equips them with adaptability to adverse environmental factors including temperature fluctuations, humidity *Corresponding author, email: nvphong@hcmuaf.edu.vn Tomato Growth and Disease Control by Streptomyces BT02 – Lê Thanh Đạm et al. 107 variations, oxygen content, nutrient availability, and the presence of toxic substances. Streptomyces species produce an array of secondary metabolites with biocontrol activities against plant parasitic fungi, thereby contributing to their significance in agriculture (Nazari et al. 2023). These secondary metabolites encompass phytohormones, siderophores, enzymes, volatile organic compounds (VOCs), antibiotics, and various other bioactive substances. Streptomyces biocontrol strains, leveraging both direct antimicrobial activity and the induction of plant resistance through indirect biosynthetic pathways, show high promise for plant protection and as growth-promoting agents in agricultural contexts. Streptomyces species also showcase insecticidal, antibacterial, and antifungal activities, further enhancing their potential applications in sustainable agriculture. Fusarium root rot, induced by Fusarium solani, constitutes a significant threat in tomato production regions. Streptomyces species have shown inhibitory effects against this phytopathogenic fungus. Streptomyces kebangsaanensis, isolated from a Malaysian ethnomedicinal plant, displayed antifungal activity against F. solani isolates, with the contained phenazine-1-carboxylic acid (PCA) exhibiting enhanced inhibitory effects in combination with amphotericin B (Elshafie & Camele 2022). Another Streptomyces strain, S. sasae TG01, inhibited the growth of both F. solani and F. oxysporum, suggesting its potential as a biocontrol agent (Mazlan et al. 2020), while the biological control Streptomyces strain, Streptomyces sp. Lnu-12 exhibited high inhibition activity against melon Fusarium, Fulvia fulva, and Alternaria solani indicating its potential to control soil-borne diseases in vegetables (Bubici 2018). Streptomyces rochei has been extensively investigated in various contexts, with strain IDWR19 demonstrating significant plant growth- promoting (PGP) activities, enzyme production, and positive effects on plant growth, manifesting as a 12.2% increase in shoot length and a 1.8-fold increase in biomass (Jog et al. 2012). In a previous study, S. rochei (MT122809) emerged as a potential antagonist to various pathogens, producing microbial volatile organic compounds (mVOCs) that inhibited the growth of sorghum grain mold pathogens while enhancing plant growth (Sudha et al. 2022). Streptomyces rochei ACTA1551 exhibited robust suppression of Fusarium oxysporum in vitro and also protected tomato seeds from infection in vivo, demonstrating potential as a biocontrol agent against the pathogen (Kanini et al. 2013), while S. rochei AMET 311 strain exhibited in vitro activity against Rhizoctonia solani (Venkatramani & Jayaprakashvel 2023). This study elucidated the characteristics associated with the ability of Streptomyces rochei BT02 to promote plant growth and control Fusarium solani, the causal agent of tomato root rot disease. Insights garnered from this investigation will provide a foundation for better selection and formulation of bioproducts conducive to sustainable agriculture. MATERIALS AND METHODS Materials Strains of Streptomyces rochei PN02 and Fusarium solani were isolated, identified, and preserved at the Plant Integrated Biology (PIB) Laboratory of Nong Lam University, Ho Chi Minh City (Tân et al. 2023). Phu Nong F1 (T-11) tomato seeds were utilized in this study. Determination of the ability of Streptomyces rochei PN02 to promote plant growth Bacterial cultures were incubated in Gause 1 or ISP2 media for 5-7 days at 30ºC with shaking at 150 rpm. The bacterial suspension was prepared with an optical density of 0.1 at 600 nm. All experiments were conducted in a completely randomized design with four replicates. The cellulolytic capability of bacteria is determined by clear yellow halos around the bacterial colonies on CMC agar medium (Teather and Wood 1982). The ability to dissolve phosphate was assessed by the appearance of a clear zone of Ca3(PO4)2 on Pikovskaya’s agar medium after 7 days of cultivation at 30C (Nautiyal 1999). Indole-3- acetic acid (IAA) production by bacterial strains cultured in ISP2 medium was detected and quantified using the Salkowski reagent colorimetric method at a wavelength of 520 nm (Sasirekha et al. 2012). Gibberellic acid (GA) production was quantified using the extraction method with ethyl acetate, and absorbance was measured at 254 nm (Berríos et al. 2004). The ability to form biofilms was determined using the BIOTROPIA Vol. 31 No. 1, 2024 108 method described by O’Toole et al. (O’Toole et al. 2000) using Gause 1 medium. Siderophore production was assessed on CAS agar medium according to Srinivas et al. (Srinivas et al. 2020), and nitrogen fixation of the bacterial strains was determined according to Bashan et al. (Bashan et al. 1998). Investigation of the influence of Streptomyces rochei BT02 on tomato plant growth As in vitro conditions, the tomato seeds were sterilized and soaked in a bacterial suspension (109 CFU/mL) for 60 minutes. At least 30 seeds were sown in Petri dishes containing moistened cotton wool and incubated at 25 ± 1°C. Seed germination was monitored after 2, 4, and 7 days. Six germinated 2-day-old tomato seeds were placed on water agar medium and divided into two sections. A paper disk soaked in 20 µL of bacterial solution (109 CFU/mL) was placed 2.5 cm from the root tip. Distilled water was used as a control. The medium plates were positioned vertically in a growth chamber and co-cultivation was carried out for 5 days under conditions of 16 hours light/8 hours dark at 25°C and 70% humidity. Parameters including germination rate (%), sprout length (cm), plumule length (cm), radicle length (cm), and seed vigor were recorded (Thilagam & Hemalatha 2019). Under greenhouse conditions, healthy tomato seedlings with three fully developed leaves were transplanted into pots (25 x 21 cm) containing clean soil, manure, lime, and phosphate fertilizer at a ratio of 4:1:1:1. When the plants had five true leaves, 8 mL of bacterial culture (107 CFU/mL) was irrigated at the base of each plant, and repeated once a week for four weeks. Plant height, leaf number, branch number, inflorescence, flower number, and fruit quality were monitored (Dias et al. 2017). Evaluation of the antagonistic ability of Streptomyces rochei BT02 against Fusarium solani The dual culture method was performed according to Ferreira et al. (1991) by measuring the fungal colony radius and calculating the antagonistic efficacy following the formula of Moayedi (2010), and the rating scale of Soytong (Soytong 2010). The agar well diffusion method was performed according to Sharma et al. (2017). All antagonistic activity of bacteria was demonstrated through the formation of inhibition zones after a 48-hour incubation period, calculated using the formula of Azman et al. (2017). The experiments were arranged in a completely randomized design and repeated three times with four Petri dishes in each replication. Healthy tomato seedlings with three fully developed leaves were transplanted into pots (25 x 21 cm) containing clean soil, manure, lime, and phosphate fertilizer at a ratio of 4:1:1:1. When the plants had five true leaves, root injury was created, followed by irrigation of 5 mL of F. solani spore suspension (106 spores/mL) and 8 mL of a bacterial suspension (107 CFU/mL) around the plant base, simultaneously or after fungal inoculation depending on the treatment. The experiments were arranged in a randomized complete block design, with each treatment replicated three times and four pots per treatment. The pots were placed in a greenhouse, and watering was provided as per the plant requirements. Disease incidence (%) and disease index (%) after infection at 7, 14, 21, and 28 days were recorded, and the AUDPC value was calculated according to Jeger & Viljanen- Rollinson (2001). The efficacy of disease control was calculated according to Abbott (1925). Data analysis The experimental data were analyzed by Analysis of Variance (ANOVA), with means compared using Duncan’s test. The data were transformed to ensure compliance with the normal distribution if necessary. RESULTS AND DISCUSSION Plant growth-promoting ability of Streptomyces rochei BT02 Under in vitro conditions, the BT02 strain demonstrated the ability to degrade cellulose, solubilize phosphate, synthesize IAA, form biofilms, and produce siderophores. However, it did not produce gibberellic acid or fix nitrogen (Table 1). Seeds treated with the BT02 strain exhibited a germination rate of 92.5% after 72 hours, compared to the control at 67.8%. Notably, BT02-treated seeds showed longer Tomato Growth and Disease Control by Streptomyces BT02 – Lê Thanh Đạm et al. 109 sprouts (1.10 cm), radicle length (4.02 cm), and increased vigor (569.8), with statistically significant differences (p<0.01) (Table 2; Figure 1). Under greenhouse conditions at 28 days after inoculation, plants treated with the BT02 strain reached a height of 79.6 cm, surpassing the control plants at 74.7 cm. The BT02 treatment significantly influenced plant growth, demonstrating increases in the number of leaves (19.4), branches (1.30), inflorescence (7.30), and flowers (14.3) (p<0.05) (Table 3; Figure 2). After 56 days of inoculation, the BT02 strain treatment resulted in the highest number of 6.50 fruits per plant. Parameters including fruit weight, fruit diameter, and fruit flesh thickness were significantly higher than the control (p<0.05) (Table 4). Table 1 Characteristics related to plant growth-promoting ability of Streptomyces rochei BT02 CMC (mm) Phosphorus solubilization index IAA concentration (g/mL) Biofilm formation Siderophore production Gibberellic acid (g/mL) Nitrogen fixation 24.67 ± 2.67 1.56 ± 0.22 11.50 ± 0.46 + + - - Table 2 Effect of Streptomyces rochei BT02 on seed germination and vigor Treatment Germination rate (%) Sprout length (cm) Plumule length (cm) Radicle length (cm) Seed vigor Control 67.8a ± 4.92 0.57 a ± 0.41 2.33 ± 0.29 2.83a ± 0.35 349.8 BT02 92.5b ± 2.94 (26.7%) 1.10b ± 0.19 (48.1%) 2.16 ± 0.43 4.02b ± 0.33 (29.6%) 569.8 (38.6%) Note: Numbers with the same superscript indicate non-significant statistical differences (α = 0.05). Figure 1 Influence of Streptomyces rochei BT02 on tomato seed germination (A-B) 4 days after inoculation; (C) 7 days after inoculation. Table 3 Influence of Streptomyces rochei BT02 on growth of tomato plants under greenhouse conditions Parameter Treatment 7 DAI 14 DAI 21 DAI 28 DAI Plant height (cm) Control 16.4b ± 1.20 29.3b ± 2.28 52.4b ± 2.24 74.7b ± 2.00 BT02 21.5a ± 1.96 (23.7%) 35.9a ± 2.11 (18.3%) 56.9a ± 2.16 (7.9%) 79.6a ± 2.80 (6.1%) Number of leaves Control 7.10 ± 0,70 10.1 ± 0.94 15.2 ± 1.07 18.9 ± 0.94 BT02 7.50 ± 0,67 10.7 ± 0.90 15.8 ± 0.97 19.4 ± 1.20 Number of branches Control 0.10b ± 0.30 0.60 b ± 0.49 BT02 0.70a ± 0.46 (85.7%) 1.30a ± 0.46 (53.8%) Inflorescence Control 0.40b ± 0.49 2.20 b ± 0.60 3.80b ± 0.60 5.30b ± 0.46 BT02 0.80a ± 0.40 (50%) 3.10a ± 0.53 (29.0%) 4.90a ± 0.30 (20.4%) 7.30a ± 0.46 (27.3%) Flowers Control 0.50 ± 0.67 4.01a ± 1.09 8.40a ± 0.80 12.0a ± 1.61 BT02 1.10 ± 0.70 5.10b ± 0.53 (21.5%) 11.0b ± 1.41 (23.6%) 14.3b ± 1.26 (16.0%) BIOTROPIA Vol. 31 No. 1, 2024 110 Numbers with the same superscript indicate non-significant statistical differences (α = 0.05). DAI: days after inoculation. Streptomyces species distributed globally possess the capacity to enhance growth in diverse crops, serving as versatile agents in roles such as root bacteria treatments, biopesticides, biofertilizers, and bio stimulants (Ryu et al. 2003). The mechanisms underlying the promotion of plant growth by PGPR encompass the synthesis of plant growth regulators and the production of siderophores, hydrocyanic acid, antibiotics, and volatile compounds. Streptomyces species contribute to crop productivity through competition, induction of systemic resistance, and mineral solubilization such as phosphorus or potassium (de Andrade et al. 2023). Furthermore, these species exhibit biological control activity against phytopathogens by colonizing plant roots and producing antifungal metabolites, providing a sustainable alternative to chemical fungicides. This study explored the plant growth- promoting impact of S. rochei BT02 on tomato plants and its antagonistic activity against Fusarium solani through both Petri dish and pot experiments. Our findings revealed that S. Rochei BT02 possessed plant growth-promoting characteristics such as the biosynthesis of IAA, phosphate solubilization, and the formation of biofilms and siderophores. Treatment with the bacterial suspension significantly enhanced the germination and growth performance of seedlings in Petri dishes, attributed in part to IAA biosynthesis and secretion by S. rochei BT02. As well as regulating apical dominance, cell elongation, and primary and secondary root growth, IAA induces the relaxation of root cell walls, thereby promoting overall plant growth (Wang et al. 2009). The BT02 strain also demonstrated positive effects on plant growth, as evident in the various growth and fruit quality parameters. Our results supported the potential application of S. rochei BT02 as a PGPR strain for sustainable agriculture. Antagonistic ability against Fusarium solani by Streptomyces BT02 In the dual culture method, PN02 exhibited resistance rates of 58.9%, while in the agar well diffusion method, PN02 showed antagonistic efficiency of 45.3% (Figure 3). Table 4 Fruit quality at 56 days after inoculation Treatment Number/plant Fresh weight (g) Length (cm) Diameter (cm) Fruit flesh thickness (mm) Control 4.10b± 1.10 42.0b ± 2.76 3.19± 0.24 3.78b±0.34 3.34b±0.17 BT02 6.50a± 1.35 (36.9%) 53.8a ± 4.71 (21.9%) 3.47± 0.46 4.45a±0.38 (15.0%) 4.38a±0.47 (23.7%) Note: Numbers with the same superscript indicate non-significant statistical differences (α = 0.05). Figure 2 Tomato plants at 28 days after inoculation with Streptomyces rochei BT02 CT: control; BT02: Streptomyces rochei BT02. Tomato Growth and Disease Control by Streptomyces BT02 – Lê Thanh Đạm et al. 111 Figure 3 Inhibitory ability against Fusarium solani BT02 at 6 days after inoculation Dual culture method (A) and agar well diffusion method (B). Under greenhouse conditions at 28 DAI, following pre- and post-incubation of actinomycetes with fungal infection, disease incidence varied between 22.0% and 36.0%. The corresponding AUDPC values were 511 and 686, indicative of control effectiveness at 41.6% and 21.6%, respectively (Table 5, Figure 4). Under the experimental conditions, inoculation with S. rochei BT02 hampered the growth of the tested fungi due to the production of diverse secondary metabolites with biological activities including chitinase, cellulase, and β-1,3- glucanase (Nguyen et al. 2023). These hydrolases degrade fungal cell walls and inhibit hyphal growth (Woith et al. 2021), while bacterial- produced antimicrobial substances also impede the growth of pathogens (El-Sharkawy & Abdelrazik 2022). Table 5 Disease index (%), area under the disease progress curve (AUDPC), and control efficacy (%) of tomato root rot disease caused by Fusarium solani BT02 under greenhouse conditions Treatment Height (cm) Root length (cm) Disease incidence (%) Disease index (%) AUDPC Control efficacy (%) 28 DAI 28 DAI 28 DAI 14 DAI 21 DAI 28 DAI 28 DAI 28 DAI Control 64.5ab±2.72 23.4b±0.34 0.00 0.00 c 0.00 c 0.00 c - F. solani 52.7c±2.60 20.1c±2.04 100.0 32.0 a 60.0 a 60.0 a 875 b±133 - BT02 66.4a±4.71 26.7a±1.02 0.00 0.00 c 0.00 c 0.00 c - BT02-F. solani 64.1ab±4.59 25.5a±1.91 100.0 24.0 b 26.0 cb 22.0 cb 511 b ±109 41.6 F. solani-BT02 61.1b±2.80 23.0b±1.34 100.0 30.0 b 36.0 cb 36.0 b 686 b±167 21.6 Note: Numbers with the same superscript in the same column indicate non-significant statistical differences (α = 0.01). AUDPC: area under the disease progress curve; DAI: days after inoculation. Figure 4 Efficiency to control root rot disease of the BT02 strain +Fs: Inoculated with Fusarium solani; CT: Control; BT02: Inoculated with BT02; BT02-Fs: Inoculated with BT02 24 hours before Fusarium solani (Fs); Fs-BT02: Inoculated with BT02 24 hours after Fusarium solani (Fs). BIOTROPIA Vol. 31 No. 1, 2024 112 The application of S. rochei BT02 to tomatoes enhanced plant growth through the production of plant growth regulators, siderophores, phosphate solubilization, and resistance to pathogenic fungi by bioactive metabolites including hydrolases and antibiotics. S. rochei is categorized as a microorganism with a biosafety level of 2/4, in accordance with Directive 90/679/EEC of the European Community on biosafety. Our findings support the agricultural use of S. rochei BT02 as a PGPR strain, highlighting the exploration of both known and unknown secondary metabolites produced by this bacterial strain. This study primarily examined the potential effects of S. rochei BT02 on crop plants. However, further research is necessary to elucidate its functions, mechanisms of action, and interactions with plants and other microorganisms in the soil environment. CONCLUSIONS Streptomyces rochei BT02 showed promise as a candidate for sustainable agriculture, displaying dual functionality by enhancing plant growth through mechanisms such as IAA production, phosphate solubilization, and siderophore production, while also suppressing the pathogenic fungus Fusarium solani. These multifaceted actions established strain BT02 as a potent biofertilizer and biocontrol agent, underscoring its efficacy for sustainable agriculture. Future research should focus on understanding the molecular mechanisms of Streptomyces rochei BT02 and explore its benefits by refining application methods on various crops, thereby significantly expanding the utility and contribution of this strain to promote sustainable agricultural practices. ACKNOWLEDGMENTS This study was partially funded by Nong Lam University - Ho Chi Minh City (code: CS-SV23- KHSH-08). REFERENCES Abbott WS. 1925. A Method of Computing the Effectiveness of an Insecticide. Journal of Economic Entomology. 18(2):265–267. doi:10.1093/jee/18.2.265a. de Andrade LA, Santos CHB, Frezarin ET, Sales LR, Rigobelo EC. 2023. Plant Growth-Promoting Rhizobacteria for Sustainable Agricultural Production. Microorganisms. 11(4). doi:10.3390/microorganisms11041088. Azman N, Sijam K, Hata E, Othman R, Saud H. 2017. Screening of Bacteria as Antagonist against Xanthomonas oryzae pv. oryzae, the Causal Agent of Bacterial Leaf Blight of Paddy and as Plant Growth Promoter. Journal of Experimental Agriculture International. 16(4):1–15. doi:10.9734/jeai/2017/33697. Bashan Y, Puente ME, Myrold DD, Toledo G. 1998. In vitro transfer of fixed nitrogen from diazotrophic filamentous cyanobacteria to black mangrove seedlings. FEMS Microbiology Ecology. 26(3):165– 170. doi:10.1111/j.1574-6941.1998.tb00502.x. Berríos J, Illanes A, Aroca G. 2004. Spectrophotometric method for determining gibberellic acid in fermentation broths. Biotechnology Letters. 26(1):67–70. doi:10.1023/B:BILE.0000009463.98203.8b. Bubici G. 2018. Streptomyces spp. as biocontrol agents against Fusarium species. CABI Reviews.:1–15. doi:10.1079/PAVSNNR201813050. Dias MP, Bastos MS, Xavier VB, Cassel E, Astarita L V., Santarém ER. 2017. Plant growth and resistance promoted by Streptomyces spp. in tomato. Plant Physiology and Biochemistry. 118:479–493. doi:10.1016/j.plaphy.2017.07.017. Elshafie HS, Camele I. 2022. Rhizospheric Actinomycetes Revealed Antifungal and Plant-Growth-Promoting Activities under Controlled Environment. Plants. 11(14). doi:10.3390/PLANTS11141872. El-Sharkawy EES, Abdelrazik E. 2022. Biocontrol of Fusarium root rot in squash using mycorrhizal fungi and antagonistic microorganisms. Egyptian Journal of Biological Pest Control. 32(1):13. doi:10.1186/s41938-022-00513-x. Jeger MJ, Viljanen-Rollinson SLH. 2001. The use of the area under the disease-progress curve (AUDPC) to assess quantitative disease resistance in crop cultivars. Theoretical and Applied Genetics. 102(1):32–40. doi:10.1007/s001220051615. Jog R, Nareshkumar G, Rajkumar S. 2012. Plant growth promoting potential and soil enzyme production of the most abundant Streptomyces spp. from wheat rhizosphere. Journal of Applied Microbiology. 113(5):1154–1164. doi:10.1111/j.1365- 2672.2012.05417.x. Kanini GS, Katsifas EA, Savvides AL, Karagouni AD. 2013. Streptomyces rochei ACTA1551, an indigenous greek isolate studied as a potential biocontrol agent against fusarium oxysporum f.sp. lycopersici. BioMed Research International. 2013. Tomato Growth and Disease Control by Streptomyces BT02 – Lê Thanh Đạm et al. 113 doi:10.1155/2013/387230. Mazlan NA, Santhanam J, Zin NM, Santiago C. 2020. Effects of combination of phenazine-1-carboxylic acid from Streptomyces kebangsaanensis with amphotericin B on clinical Fusarium solani species. Malaysian Journal of Microbiology. 16(5):432–437. doi:10.21161/mjm.190603. Moayedi G. 2010. Antagonistic Activities of Trichoderma spp . on Phytophthora Root Rot of Sugar Beet. Iran Agricultural Research. 29(2):21–37. Nautiyal CS. 1999. An efficient microbiological growth medium for screening phosphate solubilizing microorganisms. FEMS Microbiology Letters. 170(1):265–270. doi:10.1016/S0378- 1097(98)00555-2. Nazari MT, Schommer VA, Braun JCA, dos Santos LF, Lopes ST, Simon V, Machado BS, Ferrari V, Colla LM, Piccin JS. 2023. Using Streptomyces spp. as plant growth promoters and biocontrol agents. Rhizosphere. 27:100741. doi:https://doi.org/10.1016/j.rhisph.2023.100741. Nguyen HNT, Ha TTM, Luong TTD, Nguyen VP. 2023. Biological characteristics and ability of Streptomyces rochei BT02 to inhibit the Ralstonia solanacearum causing bacterial wilt disease. Ministry of Science and Technology, Vietnam. 65(7):67–72. doi:10.31276/vjst.65(7).67-72. O’Toole G, Kaplan HB, Kolter R. 2000. Biofilm formation as microbial development. Annual review of microbiology. 54:49–79. doi:10.1146/annurev.micro.54.1.49. Ryu CM, Faragt MA, Hu CH, Reddy MS, Wei HX, Paré PW, Kloepper JW. 2003. Bacterial volatiles promote growth in Arabidopsis. Proceedings of the National Academy of Sciences of the United States of America. 100(8):4927–4932. doi:10.1073/pnas.0730845100. Sasirekha B, Shivakumar S, Sullia SB. 2012. Statistical optimization for improved indole-3-acetic acid (iaa) production by pseudomonas aeruginosa and demonstration of enhanced plant growth promotion. Journal of Soil Science and Plant Nutrition. 12(4):863–873. doi:10.4067/s0718- 95162012005000038. Sharma C, Singh BP, Thakur N, Gulati S, Gupta S, Mishra SK, Panwar H. 2017. Antibacterial effects of Lactobacillus isolates of curd and human milk origin against food-borne and human pathogens. 3 Biotech. 7(1):31. doi:10.1007/s13205-016-0591-7. Soytong K. 2010. Evaluation of Chaetomium-Biological Fungicide to Control Phytophthora Stem and Root Rot of Durian. Srinivas V, Gopalakrishnan S, Kamidi JP, ... 2020. Effect Of Plant Growth-Promoting Streptomyces Sp. On Plant Growth And Yield Of Tomato And Chilli. Andhra Pradesh J Agril Sci. 6(2):65–70. Sudha A, Durgadevi D, Archana S, Muthukumar A, Suthin Raj T, Nakkeeran S, Poczai P, Nasif O, Ansari MJ, Sayyed RZ. 2022. Unraveling the tripartite interaction of volatile compounds of Streptomyces rochei with grain mold pathogens infecting sorghum. Frontiers in Microbiology. 13(July):1–15. doi:10.3389/fmicb.2022.923360. Thilagam R, Hemalatha N. 2019. Plant growth promotion and chilli anthracnose disease suppression ability of rhizosphere soil actinobacteria. Journal of Applied Microbiology. 126(6):1835–1849. doi:10.1111/jam.14259. Venkatramani M, Jayaprakashvel M. 2023. Biological Control of sheath blight disease in rice using Marine Actinomycetes (Streptomycetes rochei) AMET A311 strain. International Journal of Agricultural Sciences and Veterinary Medicine. 11(2):18–22. doi:10.25303/1102ijasvm018022. Wang S, Hu T, Jiao Y, Wei J, Cao K. 2009. Isolation and characterization of Bacillus subtilis EB-28, an endophytic bacterium strain displaying biocontrol activity against Botrytis cinerea Pers. Frontiers of Agriculture in China. 3(3):247–252. doi:10.1007/s11703-009-0042-x. Woith E, Guerriero G, Hausman J-F, Renaut J, Leclercq CC, Weise C, Legay S, Weng A, Melzig MF. 2021. Plant Extracellular Vesicles and Nanovesicles: Focus on Secondary Metabolites, Proteins and Lipids with Perspectives on Their Potential and Sources. International journal of molecular sciences. 22(7). doi:10.3390/ijms22073719.