Harnessing Antimicrobial Activities of Azotobacter and Bacillus Species for Suppression of Root Rot Disease in Sugar-beet | ||||
| Egyptian Journal of Phytopathology | ||||
| Volume 53, Issue 2, December 2025, Page 90-110 PDF (1023.12 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/ejp.2025.406064.1150 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
Marwa Sayed Fouad   1; Shadia Taghian Ahmed2; Fayrouz H Abd El-Megeed3
| ||||
| 1Plant Pathology Research Institute, Agricultural Research center, Giza 12619, Egypt. | ||||
| 2Sugar Crops Research Institute, Agricultural Research Centre, Giza, Egypt. | ||||
| 3Department of Microbial Genetic Resources, National Gene Bank (NGB), Agricultural Research center, 12619, Giza, Egypt. | ||||
| Abstract | ||||
| Plant growth promoting bacteria (PGPB), Azotobacter chroococum (B1), Bacillus megaterium (B2) and B. velezenesis (B3) were evaluated for their potential against Rhizoctonia solani which is the causal agent of root rot in sugar-beet. Samples collected from three Egyptian governorates (Sharqia, Kafr El-Sheikh and Ismailia) showed the distinctive symptoms of Rhizoctonia root rot. Moreover, the in vitro pathogenicity test revealed that the most virulent isolate (MFRh, GenBank accession number LC819603) was isolated from Sakha, Kafer-El-Sheikh governorate (31.0894° N, 30.9444° E). Bacterial strains inhibited fungal growth with values ranging from 42.96±1.67% to 44.81±0.98%. They also verified for hydrolytic enzymatic activity and were positive for cellulase, chitinase and pectinase. Strain B3 has the highest enzyme index for cellulase activity with enzymatic index, 1.98±0.09. GC/MS profile analyses for the bacterial extract of the B1, B2 and B3 recorded about 13, 15 and 13 certain volatile major compounds, respectively that recognized for their antimicrobial activity. Acetonitrile, oleic acid and heptaethylene gave the highest ratio in B1, B2 and B3 extracts respectively as a major compound. Additionally, B1 extract contained 2, 3-Butanediol which is recognized as plant growth promoter. In vivo experiments indicated significant decreases in disease severity as 25.4±1.88, 27.4±1.16 and 25.8%±1.83 due to seed treatment with B1, B2 and B3 suspensions, respectively compared to positive control, being 75.2%. Metabolic performance of sugar-beet seedlings was assessed providing the highest significant values in total phenols; proline content and peroxidase activity in leaves under the infection stress upon the application of B. velezenesis as 19.82±2.05 mg/g, 0.33±0.01mg/g and 3447.00±39.17 U/g, respectively. However, the total chlorophyll content exhibited the maximum value when seeds were treated with A. chroococum alone (38.03±0.78 mg/g). | ||||
| Keywords | ||||
| Rhizoctonia solani; Beta vulgaris L; root rot; A. chroococum; B. megaterium; B. velezenesis | ||||
|
Supplementary Files
|
||||
|
Statistics Article View: 60 PDF Download: 43 |
||||
