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BACKGROUND: In initial screening, glyphosate was ineffective in controlling five Poa annua populations. These populations were tested for resistance, and studies undertaken to determine resistance mechanisms and inheritance pattern. RESULTS: Dose–response studies conducted at 16/12°C and 27/20°C on the five putative resistant populations showed low‐level resistance (1.4‐ to 2.5‐fold) to glyphosate. Shikimic acid accumulation in response to glyphosate confirmed differences among the populations, with greater shikimic acid accumulation in the susceptible population. The EPSPS gene copy number was 0.5‐ to 5.2‐fold greater in one resistant population (HT) than in the susceptible (S) population, but not in the others. EPSPS gene expression was five‐ to tenfold higher in HT compared with the susceptible population. Target site mutations, differences in glyphosate absorption or translocation or altered expression of aldo‐keto reductase (AKR) were not identified in any of the resistant populations. Crosses were successful between one resistant population and the susceptible population (P262‐16♂ ✕ S♀) and inheritance of glyphosate resistance appears to be controlled by a single, nuclear dominant gene in this population. CONCLUSION: Our study identified EPSPS gene amplification in a South Australian glyphosate‐resistant P. annua population (HT). This mechanism of resistance was not identified in the other four glyphosate‐resistant populations, and other common mechanisms were excluded. Although the resistance mechanism in some P. annua populations remains unknown, inheritance studies with one population suggest the involvement of a single dominant gene. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Phytochemical screening of chloroform and methanolic extracts of different parts of Solanum torvum and Smilax zeylanica was done. In vitro thrombolytic and anti-arthritic activities were assessed using the clot lysis method and egg albumin denaturation technique respectively. Between the chloroform and methanolic extracts, Chloroform extracts of both plants showed higher clot lysis activities (at 100 ppm solution). On the other hand, extracts of both plants performed better in terms of anti-arthritic activities (at 500 ppm solution). In the case of thrombolytic activity, between the plant extracts, the performance of S. torvum is higher compared to S. zeylanica plant. Among chloroform extracts of different plant parts, stem of S. torvum and root of S. zeylanica showed the highest, 35.44±1.89 % and 33.63±0.83 % activities respectively. Whereas, among the methanolic extracts of the plants, the root extracts of both plants showed the highest activities, 31.96±2.86 % for S. torvum and 32.01±1.46 % for S. zeylanica. In the case of anti-arthritic activity, the performance of S. zeylanica plant extracts is higher compared to that of S. torvum. Methanolic extract of leaf of S. zeylanica samples showed the best protein denaturation activity (52.38±2.12 %) followed by the Methanolic extract of stem sample of S. torvum (44.29±2.14 %). [ABSTRACT FROM AUTHOR]

An effective in vitro culture system for mature nodal segments of European plum (Prunus domestica) was established. Several important aspects of regeneration from nodal explants were studied for adaptation of European plum in Bangladesh. Leaf explants were used for callus induction and ½ MS media supplemented with 1.0 mg/l indole butyric acid (IBA) + 0.5 mg/l naphthalene acetic acid (NAA) induced low efficiency callus. The nodal segments of 1.5 cm were cut from young plants, sterilized and established in vitro. The successful cultures were achieved on MS media supplemented with 2-6 mg/l kinetin (KIN); 2, 3, 5 mg/l benzyleaminopurine (BAP) and 4 mg/l KIN combination with 2 mg/l BAP. The highest number of shoot length (1.20 ±0.15 cm), highest number of shoot (3.00±0.35 cm), and highest number of leaf (14.25±1.45) were observed at KIN 4.0 mg/l. The successful multiple shoots were achieved on MS media with 2-6 mg/l KIN, 4 mg/l KIN combination with 2 mg/l BAP. This indicates that, in general, European plum species is very responsive to in vitro regeneration from nodal segment. The shoots from micro cutting were rooted in MS media supplemented with 1.0 mg/l IBA and with 0.5 mg/l BAP; ½ MS media supplemented with 0.5 mg/l IBA + 0.5mg/l NAA and 1.0 mg/l IBA + 0.5 mg/l BAP. Regenerated plantlets successfully acclimatized to grow vigorously with no apparent phenotypic aberrations. In addition, in sense of commercial value without growth hormone achieved great result. Furthermore, the antibacterial activity of extracts of European plum was evaluated against the human pathogenic bacteria Escherichia coli, Klebsiella pneumonia, Protease mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus by agar disc diffusion method. Most of the human pathogens were resistant against commercial disk. But plum fruit extract showed good inhibition zone result (14.25 mm by crude extract against P. aeruginosa and 12.4 mm by dry extract against S. aureus). The positive results of screening of this plum for antibacterial activity forms primary platform for further phytochemical and pharmacological studies. [ABSTRACT FROM AUTHOR]

Xanthan gum is a commercially important microbial exopolysaccharide (EPS) produced by Xanthomonas campestris. X. campestris is a plant pathogen causing various plant diseases such as black rot of crucifers, bacterial leaf blight and citrus canker disease resulting in crop damage. In this study, we isolated efficient local bacterial isolates which are capable to produce xanthan gum utilizing different sources of carbon (maltose, sucrose and glucose). Bacterial isolates from different plant leaves and fruits were identified as Xanthomonas campestris based on their morphological and biochemical characteristics. Among the 23 isolates, 70% were capable of producing gum. Taro plant, considered as new bacterial host, also have the capability to produce xanthan gum. Production conditions of xanthan gum and their relative viscosity by these bacterial isolates were optimized using basal medium containing commercial carbon and nitrogen sources and various temperature and rotation. Highest level of xanthan gum (18.286 g/l) with relative viscosity (7.2) was produced (Host, Citrus macroptera) at 28 degrees C, pH 7.0, 150 rpm using sucrose as a carbon source at orbital shaker. Whereas, in lab fermenter, same conditions gave best result (19.587 g/l gum) with 7.8 relative viscosity. Chilled alcohol (96%) was used to recover the xanthan gum. FTIR studies also carried out for further confirmation of compatibility by detecting the chemical groups.