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BACKGROUND: The biocontrol potential of soil microbes can reduce the extensive use of hazardous synthetic fungicides. This study was designed to find a strain of rhizobacteria indigenous to Pakistan with potential biocontrol against early blight of tomato caused by Alternaria solani and to characterize its biocontrol mechanisms. RESULTS: Among 88 strains tested for antagonism against A. solani on agar media, S27, Dt10 and 423, identified by 16S rRNA sequencing as strains of Bacillus amyloliquefaciens, B. cereus and Stenotrophomonas rhizophila, respectively, were the most inhibitory. When applied to detached tomato leaflets in Petri dish assays, the strains reduced lesion development by over 30% compared to the control. In greenhouse pot trials, the bacterial strains reduced early blight severity by over 50%. In three field trials, all three strains applied to tomato foliage slowed early blight disease progress and reduced disease severity, with B. amyloliquefaciens S27 reducing the area under the disease progress curve by up to 70%. All three strains showed protease, catalase and oxidase activities in vitro, but none produced β‐1,3‐glucanase and only B. cereus Dt10 showed slight chitinase activity. In a greenhouse experiment in which the bacteria were applied to tomato foliage prior to pathogen inoculation, bacteria‐treated leaves had higher β‐1,3‐glucanase and chitinase levels than leaves inoculated only with the pathogen, indicating priming induction of response. CONCLUSION: Three rhizobacteria strains have the potential to control early blight of tomato under Pakistan's growing conditions, with B. amyloliquefaciens S27 being the most promising candidate for commercial development. Antagonism and induction of the priming response may be mechanisms of biocontrol by the bacterial strains. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Sugarcane (Saccharum officinarum L.) is a key cash crop, and its production is influenced by a variety of phytopathogens in different parts of the world. During consecutive field surveys, sugarcane stalks with red rot symptoms were observed in three provinces of Pakistan (Punjab, Sindh, and Khyber Pakhtunkhwa). Cane samples with visible symptoms were plated on potato dextrose agar (PDA) media. Morphological and microscopic observations identified this pathogen as Colletotrichum falcatum. Comparative molecular study of amplified sequences of ß-tubulin (Bt) and actin (ACT) genes showed 100% similarity and ITS sequence showed 99% similarity with C. falcatum. For in vitro control of red rot, eight bacterial strains from the rhizosphere of sugarcane were isolated. These strains showed variable growth inhibition of C. falcatum in dual culture method. Among all tested strains, Bacillus amyloliquefaciens and B. altitudinis exhibited best antifungal activities. Based on these results, tested bacterial strains (B. amyloliquefaciens and B. altitudinis) can be recommended as effective biocontrol agents to manage red rot disease of sugarcane. [ABSTRACT FROM AUTHOR]

Lipases with high tolerance to temperature play a significant role in industry from food manufacturing to waste management systems. Thus, there is a need to investigate these enzymes from different geographical areas to look out for a more thermo-stable one. Characterization of lipases through experimental approaches is time consuming process and sometimes the results are ambiguous due to errors. However, integration of computational technologies is quite useful for prediction of optimized conditions. Such technologies can be applied as synthetic biology, which has many major applications in engineered biological approaches for accurate prediction of effects of different physical and chemical parameters on the system. In this study, cloning and expression of a lipase gene from Bacillus amyloliquefaciens, isolated from a novel geographical region of Pakistan, in Escherichia coli DH5α cells followed by sequencing was carried out. To isolate thermostable lipase producing strains, all the samples were kept at 50 °C. Genomic DNA was isolated and signal peptide (1–32 residues) sequence was chopped (ΔSPLipase). The ΔSPLipase was amplified and expressed in Linearized p15TV-L vector. The purified lipase appeared as single band of approximately 26 kDa. Suitable conditions of factors required for maximum lipase activity such as temperature, pH, substrate, organic solvent, detergents and metal ions were predicted through synthetic biology approach and further confirmed in wet lab. The predicted suitable factors for enzyme were almost similar to those determined experimentally. The optimum enzyme activity was recorded at pH 8 and 50 °C temperature. Interestingly, the activity of enzyme was found on a number of solvents, metal ions, detergents, and surfactants. The predicted optimum values and their experimental confirmations highlights the importance of integrated synthetic biology approaches in wet lab experiments. The characterized lipase of B. amyloliquefaciens at molecular level from Pakistani strains displayed good activity on a range of factors that implies this strain to be used for application in industrial level production. [ABSTRACT FROM AUTHOR]