Flagellin and elongation factor of Bacillus velezensis (VB7) reprogramme the immune response in tomato towards the management of GBNV infection.

The present study investigates the reprogramming of plant defense system, upon interaction with MAMP (Microbe Associated Molecular Pattern) gene products including, flagellin (Flg) and elongation factor (EF-Tu) of Bacillus velezensis (VB7) and groundnut bud necrosis virus (GBNV) in tomato (Shivam). The MAMP gene products induced the plant defense genes including, PAL, PPO, LOX, JAR, MYC2 and PDF 1.2. Secondary metabolites of Bacillus spp. at 1000 parts per million (ppm) concentration effectively reduced GBNV symptom expression in cowpea (CO7) up to 83.1 % compared to untreated, GBNV inoculated, control. The secondary metabolites from B. velezensis (VB7) and B. licheniformis (Soya 1) reduced GBNV symptoms in cowpea (CO7) up to 1.7 lesions/cm2 leaf area compared to 8.6 lesions/cm2 in virus inoculated control. Further, field study revealed that the combined application of B. velezensis (VB7) and B. licheniformis (Soya1) at 1% (10 mL/L) as, soil and foliar application reduced the percent disease incidence (PDI) up to 10.5 (PDI) compared to 28.4 (PDI) in untreated control plants. Besides, it also improved the plant growth and yield up to 23.5 tonnes/ha compared to 13.8 tonnes/ha in untreated control.

Thrips diversity of cotton ecosystem and the role of parthenium pollen grains in the transmission of tobacco streak virus (TSV) infection in cotton.

Survey in the cotton fields of Coimbatore and Erode districts confirmed the presence of three different thrips species including, Scirtothrips dorsalis, Scirtothrips oligochaetus, and Frankliniella occidentalis. Their identity was confirmed through morphometric analysis and molecular characterization. Tobacco streak virus (TSV) was detected in the leaves and pollen grains of both parthenium and cotton plants collected from infected cotton fields. The presence of TSV was confirmed through immuno-detection by direct antigen coating enzyme-linked immuno sorbent assay (DAC-ELISA). Further confirmation was accomplished by reverse transcriptase polymerase chain reaction (RT-PCR) using TSV coat protein-specific primers. Other than parthenium, weed plants in the cotton field such as Trianthema portulacastrum, Boerhavia diffusa, and Amaranthus sp. were also confirmed for TSV infection through RT-PCR. Parthenium hysterophorus plants acts as a silent carrier of TSV and they occasionally produced symptoms. Among all the randomly collected thrips samples, two pooled samples were detected positive for TSV through RT-PCR. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13205-021-02967-6.

Induction of in planta resistance by flagellin (Flg) and elongation factor-TU (EF-Tu) of Bacillus amyloliquefaciens (VB7) against groundnut bud necrosis virus in tomato.

Role of plant growth promoting rhizobacteria (PGPR) in growth promotion and induction of resistance against various plant pathogens have been extensively studied. However, MAMP (Microbe Associated Molecular Pattern) triggered immunity (MTI) against plant viruses are not well exploited. The present study enlightens the role of two MAMP genes including, flagellin (Flg) and elongation factor (EF-Tu) in the induction of plant defense against GBNV infecting tomato. Secondary metabolites of Bacillus amyloliquefaciens (VB7), effectively suppressed GBNV symptom expression up to 84% compared to untreated control in cowpea, the indicator host plant. Agrobacterium tumefaciens EHA105 clones expressing the MAMP genes were drenched in the root zone to assess the induction of resistance against GBNV in tomato. Treatment with A. tumefaciens EHA105 clones containing flagellin (Ag- Ba.Flg) and elongation factor-TU (Ag-Ba.EF-Tu) genes as soil drench and foliar spray, reduced virus titre,0.369 OD and 0.379 OD respectively as compared to control 1.249 OD. The disease severity was reduced up to 15% in Ag-Ba.Flg treated plants compared to 88.25% in inoculated control. Further there was an increased expression of defense associated genes including, MAPKK1, WRKY33BB, NPR1 and PR1.The present investigation clearly indicated the efficiency of MAMP genes in triggering defense mechanism in tomato against GBNV.

Biocontrol Potentials of Antimicrobial Peptide Producing Bacillus Species: Multifaceted Antagonists for the Management of Stem Rot of Carnation Caused by Sclerotinia sclerotiorum.

Bacillus species are widely exploited as biocontrol agents because of their efficiency in impeding various plant pathogens with multifaceted approach. In this study, Bacillus species were isolated from rhizosphere of various plants viz., carnations, cotton, turmeric, and bananas in Tamil Nadu state of India. Their potential to control the mycelial growth of Sclerotinia sclerotiorum was assessed in vitro by dual plate and partition plate techniques. B. amyloliquefaciens strain VB7 was much effective in inhibiting mycelial growth (45% inhibition of over control) and sclerotial production (100%). PCR detection of AMP genes revealed that B. amyloliquefaciens (VB7) had a maximum of 10 diverse antibiotic biosynthesis genes, namely, ituD, ipa14, bacA, bacD, bamC, sfP, spaC, spaS, alba, and albF, that resulted in production of the antibiotics iturin, bacilysin, bacillomycin, surfactin, subtilin, and subtilosin. Further, metabolites from B. amyloliquefaciens strains VB2 and VB7, associated with inhibition of S. sclerotiorum, were identified as phenols and fatty acids by gas chromatography mass spectrometry (GC-MS). Delivery of bacterial suspension of the effective strains of Bacillus spp. as root dip was found promising for the management of stem rot of cultivated carnations. Minimal percent disease incidence (4.6%) and maximum plant growth promotion was observed in the plants treated with B. amyloliquefaciens (VB7).

Ofloxacin induced arthropathy in patients with multi-drug resistance tuberculosis.

Some of the 4-fluroquinolones have been reported to induce arthropathy, but so far there are no case reports of arthropathy due to ofloxacin. Two cases of ofloxacin induced arthropathy in multi-drug resistance (MDR) tuberculosis are reported and possible drug interaction with other anti-tubercular drugs is discussed.