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Soil salinity is one of the main yield-limiting factors in various crops. Under different environmental stresses, many rhizobacteria have demonstrated encouraging role in enhancing plant growth and tolerate stress conditions. In this study, three potential 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase- and exopolysaccharides (EPS)-secreting bacterial strains including Bacillus megaterium, B. tequilensis, and Pseudomonas putida have been assessed for their growth-promoting characteristics. These bacterial strains positively affected the physiology, biochemistry, and antioxidant enzymatic activities of wheat plant, under salinity stress. Results of this study depicted that the inoculation of PGPR positively invigorates growth attributes like relative water content and photosynthetic pigments of wheat seedling under saline conditions. Moreover, plants inoculated with PGPR also showed decreased concentration of malondialdehyde (MDA) and hydrogen peroxide (H2O2). Inoculation of PGPR reduced electrolytic leakage and enhanced enzymatic activity for the scavenging of reactive oxygen species (ROS). These PGPR also increased the production of proline and total soluble sugar. Expression analysis of selected genes by qPCR revealed higher expression of Salt Overly Sensitive (SOS1 and SOS4) genes and predicted their potential role in stress tolerance. These genes can be further overexpressed in wheat plant to tolerate salinity stress. On the basis of these findings, it can be concluded that the priming of seeds with aforementioned PGPR can decrease the adverse effects of salinity on wheat plant.

Broad manipulation of halotolerant plant growth promoting bacteria (PGPB) is very important in agriculture. In the present research, survival and adaptability of PGPB was determined under saline co...

Citrus is the leading fruit crop of Pakistan and exported to different parts of the world. Due to suitable weather condition, this crop is affected by different biotic factors which seriously deteriorate its quality and quantity. During the months of November 2018 to January 2019, citrus brown rot symptoms were recurrently observed on sweet oranges in National Agricultural Research Centre (NARC), Islamabad. Causal agent of citrus brown rot was isolated, characterized, and identified as Fusarium oxysporum. For environment-friendly control of this disease, leaf extract of Azadirachta indica was used for the green synthesis of iron oxide (Fe2 O3 ) nanoparticles. These nanoparticles were characterized before their application for disease control. Fourier transform infrared spectroscopy (FTIR) of these synthesized nanoparticles described the presence of stabilizing and reducing compounds like alcohol, phenol, carboxylic acid, and alkaline and aromatic compounds. X-Ray diffraction (XRD) analysis revealed the crystalline nature and size (24 nm) of these nanoparticles. Energy dispersive X-Ray (EDX) analysis elaborated the presence of major elements in the samples. Scanning electron microscopy (SEM) confirmed the spinal shaped morphology of prepared nanoparticles. Successfully synthesized nanoparticles were evaluated for their antifungal potential. Different concentrations of Fe2 O3 nanoparticles were used and maximum mycelial inhibition was observed at 1.0 mg/ml concentration. On the basis of these findings, it could be concluded that Fe2 O3 nanoparticles, synthesized in the leaf extract of A. indica, can be successfully used for the control of brown rot of sweet oranges.

Differentially expressed genes help in exploring plant defense mechanism under variable stress conditions. In current investigation, RNA sequencing was executed to explore the differential gene expression in resistant and susceptible varieties of Cotton (Gossypium hirsutum), upon infection with Aspergillus tubingensis. Comparative RNA-Seq of control and infected plants was performed using Illumina HiSeq 2,500. Overall 79.84 G clean data was generated and 6,558 DEGs were identified in both varieties, in response to pathogen inoculation. Differentially expressed genes were found to be involved in defense, antifungal response, signaling pathways, oxidative burst and transcription. Genes involved in defense responses, MAPK signaling, cell wall fortification and signal transduction were highly induced in resistant variety. Real time PCR also revealed the up regulation of MAPKKK YODA like, L-ascorbate oxidase, late embryogenesis abundant protein (At1g64065) and flavonoid 3',5'-hydroxylase-like, in resistant variety. Elevated accumulation of such DEGs in resistant variety could function as the source for identifying biomarkers for breeding and these can be used as potential candidate genes for transgenic manipulation. Their study also helped in understanding complex plant-fungal interaction and advanced the understanding of plant-microbe interaction. Inclusively, our findings provide an indispensable foundation for advanced understanding of the plant resistance mechanisms of cotton.

Aspergillus tubingensis is a causative known pathogen of various important crops, worldwide. The existing study was aimed to examine the virulence potential of A. tubingensis on resistant (NIA-Sadori) and susceptible (CIM-573) cultivars of cotton. For this purpose, both cultivars were inoculated with pathogen and altered morphology of diseased leaves was observed with light and scanning electron microscope. Disease severity was measured and estimated to be 68.7 and 27.1% in susceptible and resistant cultivars, respectively. To understand and compare defense mechanism of resistant and susceptible cultivars, different biochemical and enzymatic changes were observed. After the infection of A. tubingensis, increase in the concentrations of sugar, total protein, proline, phenol, and phenylalanine ammonia lyase (PAL) was more prominent in resistant cultivar, than the susceptible one. Moreover, due to increased number of dead cells, significantly higher electrolyte leakage was detected in susceptible cultivar. Principal component analysis confirmed the effect of A. tubingensis on growth attributes and various physiological and biochemical activities of cotton. These findings help us to suggest a possible role of proline content, protein content, and PAL activity in resistance mechanism of Cotton plant.

Green nanotechnology has become an emerging field for the control of plant disorders. In the current study, the leaf extract of Calotropis procera has been used as reducing and stabilizing agent and the preparation of iron nanoparticles has been optimised. For this purpose, the formation and morphological properties of green iron nanoparticles were investigated. The synthesized nanoparticles were characterized through fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis. FTIR spectroscopy detected the presence of stabilising and reducing molecules such as O H, C H, O C O, C O and C O. XRD analysis confirmed the orthorhombic form and size (∼32 nm) of these nanoparticles. EDX analysis gave information about the presence of major elements in the samples while the spinal shaped morphology of prepared iron nanoparticles was described by SEM. After successful preparation, iron nanoparticles were evaluated for their potential antifungal activity. Using poisoned food technique, different concentrations of nanoparticles were used to assess growth inhibition of Alternaria alternata. Iron nanoparticles showed highly significant growth reduction and the maximum growth inhibition (87.9 %) was observed at 1.0 mg/mL concentration of nanoparticles. These results reveal that the iron nanoparticles, prepared in the leaf extract of C. procera are very efficient, cost-effective and eco-friendly. These proficient results suggest the large scale use of these green nanoparticles, as an effective alternative to chemical fungicide.

Citrus is the leading fruit crop of Pakistan and exported to different parts of the world. Due to suitable weather condition, this crop is affected by different biotic factors which seriously deteriorate its quality and quantity. During the months of November 2018 to January 2019, citrus brown rot symptoms were recurrently observed on sweet oranges in National Agricultural Research Centre (NARC), Islamabad. Causal agent of citrus brown rot was isolated, characterized, and identified as Fusarium oxysporum. For environment-friendly control of this disease, leaf extract of Azadirachta indica was used for the green synthesis of iron oxide (Fe

Yellow oleander (Thevetia peruviana J.) is grown as an ornamental shrub in Pakistan. A severe rot was observed on fruit of yellow oleander in different areas of Islamabad, Wah and Taxila, Pakistan ...

Due to various anthropogenic activities, different heavy metals like arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg) and nickel (Ni) accumulate in the soils of industrial areas. In the current study, contaminated soil was collected from Yuepu industrial area of Shanghai, China. Soil analysis revealed the presence of Pb and Cu in high concentrations, ranging from 125.9–128.0 mg/kg and 98.4–100.2 mg/kg, respectively. These soil samples were further used to isolate metal tolerant microbes. Subsequent screening resulted in the isolation of four major fungal species including Fusarium fujikuroi, Fusarium solani, Trichoderma citronoviridae and Trichoderma reesei. Molecular characterization of isolated fungi was performed and amplified sequences were deposited in GenBank NCBI database. Metal tolerance and biosorption capacity of these fungal strains towards lead and copper were tested. Fungal strains were exposed to increasing concentrations (100–1000 ppm) of chlorides of lead and copper and the tolerance of the selected fungi was evaluated by measuring the minimum inhibitory concentrations (MIC). The range of MIC values was found to be 400 ppm to 1000 ppm. The tolerance index of all the tested fungi was calculated and T. citronoviridae was observed to be tolerant at 1 mM concentration of lead while F. solani was the most tolerant species at 1 mM concentration of copper. The highest biosorption capacity of Pb was exhibited by T. citronoviridae, while T. reesei showed the best absorption capacity of Cu followed by F. solani. Scanning electron microscopy (SEM) showed visible adsorption of metal on fungal mycelia and suggested it to be the mechanism of metal removal. On the basis of these findings, it could be concluded that T. citronoviridae and F. solani are the potential mycoremediation microbes in Pb and Cu contaminated soils, respectively.

Aspergillus tubingensis is an important pathogen of economically important crops. Different biotic stresses strongly influence the balance of metabolites in plants. The aim of this study was to understand the function and response of resistance associated metabolites which, in turn are involved in many secondary metabolomics pathways to influence defense mechanism of cotton plant. Analysis of non-targeted metabolomics using ultra high performance liquid chromatography–mass spectrometry (UPLC-MS) revealed abundant accumulation of key metabolites including flavonoids, phenylpropanoids, terpenoids, fatty acids and carbohydrates, in response to leaf spot of cotton. The principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and partial least squares discriminant analysis (PLS-DA) score plots illustrated the evidences of variation between two varieties of cotton under mock and pathogen inoculated treatments. Primary metabolism was affected by the up regulation of pyruvate and malate and by the accumulation of carbohydrates like cellobiose and inulobiose. Among 241 resistance related (RR) metabolites, 18 were identified as resistance related constitutive (RRC) and 223 as resistance related induced (RRI) metabolites. Several RRI metabolites, identified in the present study were the precursors for many secondary metabolic pathways. These included phenylpropanoids (stilbenes and furanocoumarin), flavonoids (phlorizin and kaempferol), alkaloids (indolizine and acetylcorynoline) and terpenoids (azelaic acid and oleanolic acid). Our results demonstrated that secondary metabolism, primary metabolism and energy metabolism were more active in resistant cultivar, as compared to sensitive cultivar. Differential protein and fatty acid metabolism was also depicted in both cultivars. Accumulation of these defense related metabolites in resistant cotton cultivar and their suppression in susceptible cotton cultivar revealed the reason of their respective tolerance and susceptibility against A. tubingensis.