Susceptibility of flexible plastic foodstuffs packaging against Monomorium indicum (Hymenoptera: Formicidae) household ants.

Ants belonging to the Monomorium indicum (Formicidae: Hymenoptera) species are ubiquitous insects that are commonly associated with household settings in Pakistan. Packaged foodstuffs are easily destroyed by household ants when packaging is made with materials that have a high susceptibility. This study evaluated the susceptibility of three common flexible plastic packaging materials namely: opaque polyethylene, transparent polyethylene and polypropylene, which were each tested at thicknesses of 0.02 mm for their susceptibility against M. indicum. Except opaque polyethylene which is only available at 0.02 mm thickness, both transparent polyethylene and polypropylene were tested at higher thickness of 0.04 mm and 0.06 mm also against M. indicum. In order to simulate household settings, experiments were conducted at the faculty building of the agriculture and environment department of The Islamia University of Bahawalpur, Pakistan during summer vacations when the building was quiet. Different corners were selected near water sources for maximum exposure to the largest number of ants. Experimental cages used for the experiment were built with wood and 2 mm iron gauze to allow only ants to enter the cages. Daily activity of ants was used as an infestation source in cages. Experiments were run over three time spans of fifteen days each from June 20th 2022 to August 15th 2022. Results showed all packaging materials were susceptible against M. indicum at the 0.02 mm thickness level. Polypropylene was susceptible at 0.04 mm thickness but resistant to ants at 0.06 mm thickness, whereas polyethylene was still susceptible to ants at the higher thickness of 0.06 mm. Correlation of packaging damage with weather factors showed that temperature had a positive relationship, while relative humidity had a negative association with M. indicum attack. Overall correlation of packaging damage with packaging thickness showed packaging thickness was negatively associated with packaging damage from the ants. Because major cutting role is performed by the mandibles, we studied mandibles of ants and three frequent pests of packaged foodstuff namely Rhyzopertha dominica, Tribolium castaneum and Trogoderma granarium. The results showed that ants had the largest mandible and frontal mandibular tooth lengths compared with the mandibles and frontal teeth of the common stored product pests, indicating M. indicum household ants have a higher pest status for packaged foodstuffs compared to common stored product pests. Although the thickness of the flexible plastic packaging was a major factor against household ants, the study results recommend the use of polypropylene with a thickness of at least 0.06 mm as foodstuff packaging against household ants compared with polyethylene packaging, which was found to be susceptible to ants even at 0.06 mm thickness.

Laboratory Evaluation of Storage Bags for Infestations in Wheat Caused by Rhyzopertha dominica F. (Coleoptera: Bostrichidae) and Trogoderma granarium Everts (Coleoptera: Dermestidae) and Their Control Using Phosphine Fumigation.

Bag storage of wheat is common in Asian countries, and common types of such bags include jute bags, woven plastic bags, and hermetic plastic bags. In order to assess infestation by two serious pests, namely Rhyzopertha dominica (Coleoptera: Bostrichidae) and Trogoderma granarium (Coleoptera: Dermestidae) in these bags, two experiments were performed. In the first experiment, three popular wheat varieties, namely Akbar, Dilkash, and Bakhar star were filled in above-mentioned miniature-size bags which were then placed in jars with three replicates per bag type and variety. Forty insects (adults for R. dominica and larvae for T. granarium) were released in the center of the jars for a period of 30 d in two different setups for both species. Data were recorded twice: after 15 d and 30 d. Results showed insects entered the jute bags only (made invasions due to its loose fibers and openings). Inside the bags, R. dominica caused more weight loss and live insects in Dilkash and Akbar varieties, while T. granarium preferred Bakhar star and Dilkash compared with their third variety. In the second experiment, only two bags, namely woven plastic bags and hermetic plastic bags filled with one variety, were tested to check damage (penetrations because no openings are present in these bags as in jute bags) to the bags. Results showed both species created holes in woven plastic bags but not in hermetic plastic bags. These results showed hermetic plastic bags remained safe from external infestation compared with the other two bags. Sometimes if insects are already present in the grains inside the bags, fumigation is needed from outside to kill the pests inside. To evaluate this, all three bags were filled with a wheat variety and were also infested with both insect species and placed in a fumigation container with nine replicates per bag type. A phosphine tablet (3.0 g) wrapped in muslin cloth was placed in a container which was then sealed, and the fumigation-induced mortality after 24 h was recorded. Results showed mortality was >95% to 100% in woven and jute bags, respectively, while mortality in hermetic plastic bags remained very low (<3%). These results revealed the least fumigant gas permeation in hermetic plastic bags compared with jute and woven plastic bags. Results of all three experiments demand immediate alteration in creation of all three bags to curtail infestation from outside (jute and woven plastic bags) as well as to generate maximum fumigation efficacy when the source of infestation is with the grains (hermetic bags).

Assessing the potential of exogenous caffeic acid application in boosting wheat (Triticum aestivum L.) crop productivity under salt stress.

Caffeic acid (CA) is known as an antioxidant to scavenge reactive oxygen species (ROS), but the underlying mechanism of mediation of plant salt tolerance against various abiotic stresses by caffeic acid is only partially understood. A field experiment (120 days duration) was conducted to investigate the protective role of caffeic acid under a high saline medium (EC 8.7 dS m-1 and textural class: sandy loam) in two wheat genotypes (FSD -08 and Zincol-16). Two levels of caffeic acid (50 µM and 100 µM) were applied exogenously in combination with the salinity stress and results revealed that salt alleviation is more prominent when caffeic acid was applied at the rate of 100 µM. Under saline conditions, wheat genotypes show poor fresh and dry matter accumulation, chlorophyll contents, relative water contents (RWC), membrane stability index (MSI) and activities of antioxidant enzymes and increased uptake of Na+ ions. However, wheat genotype FSD-08 eminently responded to caffeic acid application as compared to wheat genotype Zincol-16 as demonstrated by higher growth indicators, RWC, MSI, activities of antioxidant enzymes, accumulation of mineral ions in grain along with yield attributes. In addition, caffeic acid also mitigated salt-induced oxidative stress malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents as well as significantly reduced Na+ uptake. It can be concluded that caffeic acid-induced salinity tolerance in wheat is attributed to improved plant water relations, K+ uptake, yield contents and activities of antioxidant stress enzymes.

Biochar Mediated-Alleviation of Chromium Stress and Growth Improvement of Different Maize Cultivars in Tannery Polluted Soils.

Soil pollution with heavy metal is a serious problem across the globe and is on the rise due to the current intensification of chemical industry. The leather industry is one of them, discharging chromium (Cr) in huge quantities during the process of leather tanning and polluting the nearby land and water resources, resulting in deterioration of plant growth. In this study, the effects of biochar application at the rate of 3% were studied on four maize cultivars, namely NK-8441, P-1543, NK-8711, and FH-985, grown in two different tannery polluted Kasur (K) and Sialkot (S) soils. Maize plants were harvested at vegetative growth and results showed that Cr toxicity adversely not only affected their growth, physiology, and biochemistry, but also accumulated in their tissues. However, the level of Cr toxicity, accumulation, and its influence on maize cultivars varied greatly in both soils. In this pot experiment, biochar application played a crucial role in lessening the Cr toxicity level, resulting in significant increase in plant height, biomass (fresh and dry), leaf area, chlorophyll pigments, photosynthesis, and relative water content (RWC) over treatment set as a control. However, applied biochar significantly decreased the electrolyte leakage (EL), antioxidant enzymes, lipid peroxidation, proline content, soluble sugars, and available fraction of Cr in soil as well as Cr (VI and III) concentration in root and shoot tissues of maize plant. In addition to this, maize cultivar differences were also found in relation to their tolerance to Cr toxicity and cultivar P-1543 performed better over other cultivars in both soils. In conclusion, biochar application in tannery polluted soils could be an efficient ecofriendly approach to reduce the Cr toxicity and to promote plant health and growth.

Application of abscisic acid and 6-benzylaminopurine modulated morpho-physiological and antioxidative defense responses of tomato (Solanum lycopersicum L.) by minimizing cobalt uptake.

A hydroponic study was conducted to determine the effects of single and/or combined application of different doses (0, 5 and 10 µM L-1) of abscisic acid (ABA) and 6-benzylaminopurine (BAP) on cobalt (Co) accumulation, morpho-physiological and antioxidative defense attributes of tomato (Solanum lycopersicum L.) exposed to severe Co stress (400 µM L-1). The single Co treatment (T1), prominently decreased tomato growth, relative water contents, photosynthetic pigments (chlorophyll a and chlorophyll b), whereas enhanced oxidative stress and Co accumulation in shoot and root tissues. Nonetheless, the supplementation of ABA and 6-BAP via nutrient media significantly (P < 0.05) enhanced plant biomass, root morphology and chlorophyll contents of tomato, compared to only Co treatment (T1). Moreover, the oxidative stress indicators such as malondialdehyde, proline and H2O2 contents were ameliorated through activation of enzymatic antioxidant activities i.e. ascorbate peroxidase, superoxide dismutase, catalase, and peroxidase, in growth modulator treatments in comparison to T1. The Co uptake, translocation (TF) and bioaccumulation factor (BAF) by shoot and root tissues of tomato were significantly reduced under all the treatments than that of T1. The supply of 6-BAP alone or in combination with ABA at 10 µM L-1 application (T7) rate was found the most effective to reduce Co accumulation in the roots and shoots by 48.4% and 70.2% respectively than T1 treatment. It can be concluded that two plant growth modulators could improve the stress tolerance by inhibition of Co uptake in tomato plants.

Integrated use of phosphate-solubilizing Bacillus subtilis strain IA6 and zinc-solubilizing Bacillus sp. strain IA16: a promising approach for improving cotton growth.

Mineral nutrition of crop plants is one of the major challenges faced by modern agriculture, particularly in arid and semi-arid regions. In alkaline calcareous soils, the availability of phosphorus and zinc is critically less due to their fixation and precipitation as complexes. Farmers use fertilizers to fulfill crop requirements, but their efficacy is less, which increases production costs. Plant growth-promoting rhizobacteria (PGPR) can improve the availability of crop nutrients through solubilizing the insoluble compounds of phosphorus and zinc in soil. In the present study, a total of 40 rhizobacterial isolates were isolated from cotton rhizosphere and screened for improving cotton growth through the solubilization of phosphorus and zinc. Out of these 40 isolates, seven isolates (IA2, IA3, IA6, IA7, IA8, IA13, and IA14) efficiently solubilized insoluble rock phosphate while seven isolates (IA10, IA16, IA20, IA23, IA24, IA28, and IA30) were more efficient in solubilizing insoluble zinc oxide. In liquid media, strain IA7 (2.75 µg/mL) solubilized the highest amount of phosphate while the highest concentration of soluble zinc was observed in the broth inoculated with strain IA20 (3.94 µg/mL). Seven phosphate-solubilizing and seven zinc-solubilizing strains were evaluated using jar trial to improve the growth of cotton seedlings, and the results were quite promising. All the inoculated treatments showed improvement in growth parameters in comparison with control. Best results were shown by the combined application of IA6 and IA16, followed by the combination of strains IA7 and IA20. Based on the jar trial, the selected isolates were further characterized by plant growth-promoting characters such as siderophores production, HCN production, ammonia production, and exopolysaccharides production. These strains were identified through 16S rRNA sequencing as Bacillus subtilis IA6 (accession # MN005922), Paenibacillus polymyxa IA7 (accession # MN005923), Bacillus sp. IA16 (accession # MN005924), and Bacillus aryabhattai IA20 (accession # MN005925). It is hence concluded that the integrated use of phosphate-solubilizing and zinc-solubilizing strains as potential inoculants can be a promising approach for improving cotton growth under semi-arid conditions.

Plant-growth-promoting Bacillus and Paenibacillus species improve the nutritional status of Triticum aestivum L.

Wheat is one of the best-domesticated cereal crops and one of the vital sources of nutrition for humans. An investigation was undertaken to reveal the potential of novel bio-inoculants enriching micronutrients in shoot and grains of wheat crop to eliminate the hazards of malnutrition. Sole as well as consortia inoculation of bio-inoculants significantly enhanced mineral nutrients including zinc (Zn) and iron (Fe) concentrations in shoot and grains of wheat. Various treatments of bio-inoculants increase Zn and Fe content up to 1-15% and 3-13%, respectively. Sole inoculation of Bacillus aryabhattai (S10) impressively improves the nutritious of wheat. However, the maximum increase in minerals contents of wheat was recorded by consortia inoculation of Paenibacillus polymyxa ZM27, Bacillus subtilis ZM63 and Bacillus aryabhattai S10. This treatment also showed a maximum bacterial population (18 × 104 cfu mL-1) in the rhizosphere. The consortium application of these strains showed up to a 17% increase in yield. It is evident from the results that the consortium application was more effective than sole and co-inoculation. A healthy positive correlation was found between growth, yield, and the accessibility of micronutrients to wheat crops at the harvesting stage. The present investigations revealed the significance of novel bacterial strains in improving the nutritional status of wheat crops. These strains could be used as bio-inoculants for the biofortification of wheat to combat hidden hunger in developing countries.

Exopolysaccharides and indole-3-acetic acid producing Bacillus safensis strain FN13 potential candidate for phytostabilization of heavy metals.

Microbial population of soils irrigated with industrial wastewater may contain certain exopolysaccharides (EPS) and indole-3-acetic acid (IAA) producing bacterial strains having the ability to tolerate heavy metals along with plant growth-promoting (PGP) traits. As cadmium is one of the most toxic heavy metals for soils, plants, animals, and human beings, the present study was planned to isolate and characterize EPS- and IAA-producing, Cd-tolerant bacterial strains having tolerance against heavy metals along with plant growth-promoting traits. A total of 30 rhizobacterial strains (FN1-FN30) were isolated from rhizosphere soil collected from fields around industrial areas and roadsides irrigated with industrial wastewater. Out of these, eight isolates with the combined ability of IAA production and EPS production were characterized for PGP traits. On the basis of multifarious PGP traits and the results of root colonization assay, three most efficient EPS- and IAA-producing, Cd-tolerant plant growth-promoting strains, i.e., FN13, FN14, and FN16, were selected for multiple metal (Cd, Pb, Ni, and Cu) tolerance test along with quantification of growth, and IAA and EPS production abilities under Cd stress. Increasing levels of Cd stress negatively affected the tested characteristics of these strains, but FN13 showed more stability in growth, IAA production (18.24 µg mL-1), and EPS production (148.99 µg mL-1) compared to other strains under Cd stress. The morphological and biochemical analysis confirmed FN13 as Gram-positive, rod-shaped bacteria with smooth colonies of yellow appearance. The strain FN13 has strong root colonization (3.36 × 106 CFU g-1) ability for mustard seedlings and can solubilize Zn and phosphate along with the production of HCN, ammonia, and siderophores. The 16S rRNA sequencing confirmed it as the Bacillus safensis strain FN13. It can be explored as potential phytostabilizing biofertilizer for heavy metal-contaminated soils.

Preliminary study on phosphate solubilizing Bacillus subtilis strain Q3 and Paenibacillus sp. strain Q6 for improving cotton growth under alkaline conditions.

BACKGROUND: Low phosphorus availability limits crop production in alkaline calcareous soils in semi-arid regions including Pakistan. Phosphate solubilizing bacteria may improve crop growth on alkaline calcareous soils due to their ability to enhance P availability. METHODS: Twenty rhizobacterial isolates (Q1-Q20) were isolated from rhizosphere of cotton and characterized for their growth promoting attributes in vitro. The selected phosphate solubilizing isolates were further screened for their ability to improve cotton growth under axenic conditions (jar trial). The phosphorus solubilization capacities of selected strains were quantified and these strains were identified through 16S rDNA sequencing. RESULTS: Isolates Q2, Q3, Q6, Q7, Q8, Q13 and Q14 were able to solubilize phosphate from insoluble sources. Most of these isolates also possessed other traits including catalase activity and ammonia production. The growth promotion assay showed that Q3 was significantly better than most of the other isolates followed by Q6. Maximum root colonization (4.34 × 106 cfu g-1) was observed in case of isolate Q6 followed by Q3. The phosphorus solubilization capacities of these strains were quantified, showing a maximum phosphorus solubilization by Q3 (optical density 2.605 ± 0.06) followed by the Q6 strain. The strain Q3 was identified as Bacillus subtilis (accession # KX788864) and Q6 as Paenibacillus sp. (accession # KX788865) through 16S rDNA sequencing. DISCUSSION: The bacterial isolates varied in their abilities for different growth promoting traits. The selected PGPR Bacillus subtilis strain Q3 and Paenibacillus sp. strain Q6 have multifarious growth promoting traits including ability to grow at higher EC and pH levels, and phosphorus solubilizing ability. These strains can efficiently colonize cotton roots under salt affected soils and help plants in phosphorus nutrition. It is concluded that both strains are potential candidates for promoting cotton growth under alkaline conditions, however further investigation is required to determine their potential for field application.

Zinc solubilizing Bacillus spp. potential candidates for biofortification in maize.

Bioaugmentation of Zn solubilizing rhizobacteria could be a sustainable intervention to increase bioavailability of Zn in soil which can be helpful in mitigation of yield loss and malnutrition of zinc. In present study, a number of pure rhizobacterial colonies were isolated from maize rhizosphere and screened for their ability to solubilize zinc oxide. These isolates were screened on the basis of zinc and phosphate solubilization, IAA production, protease production, catalase activity and starch hydrolysis. All the selected isolates were also positive for oxidase activity (except ZM22), HCN production (except ZM27) and utilization of citrate. More than 70% of isolates produces ammonia, hydrogen cyanide, siderophores, exopolysaccharides and cellulase. More than half of isolates also showed potential for urease activity and production of lipase. The ZM31 and S10 were the only isolates which showed the chitinase activity. All these isolates were evaluated in a jar trial for their ability to promote growth of maize under axenic conditions. Results revealed that inoculation of selected zinc solubilizing rhizobacterial isolates improved the growth of maize. In comparison, isolates ZM20, ZM31, ZM63 and S10 were best compared to other tested isolates in stimulating the growth attributes of maize like shoot length, root length, plant fresh and dry biomass. These strains were identified as Bacillus sp. (ZM20), Bacillus aryabhattai (ZM31 and S10) and Bacillus subtilis (ZM63) through 16S rRNA sequencing. This study indicated that inoculation of Zn solubilizing strains have potential to promote growth and can be the potential bio-inoculants for biofortification of maize to overcome the problems of malnutrition.

Comparison of rhizosphere properties as affected by different Bt- and non-Bt-cotton (Gossypium hirsutum L.) genotypes and fertilization.

Incorporation of genetically modified crops in the cropping system raises the need for studying the effect of these crops on the soil ecosystem. The current study aimed to compare the effect of Bacillus thuringiensis (Bt)- and non-Bt-cotton (Gossypium hirsutum L.) genotypes on rhizosphere properties under fertilized and unfertilized soil conditions. One non-Bt-cotton (IUB 75) and four Bt-cotton varieties (IUB-222, MM-58, IUB-13, FH-142) were sown in a Randomized Complete Block Design (RCBD) in a factorial fashion with three replications under unfertilized (T1) and fertilized (T2 at NPK 310-170-110 kg ha-1) soil conditions. The culturable soil bacterial population was recorded at flowering, boll opening, and harvesting stages, while other rhizosphere biological and chemical properties were recorded at harvesting. Results revealed that Bt-cotton genotypes IUB-222 and FH-142 showed significantly higher rhizosphere total nitrogen, NH4+-N, available phosphorus, and available potassium. Total organic carbon and microbial biomass carbon was also maximum in the rhizosphere of IUB-222 under fertilized conditions. Similarly, bacterial population (CFU g-1) at flowering stage and at harvesting was significantly higher in the rhizosphere of IUB-222 as compared to non-Bt- (IUB-75) and other Bt-cotton genotypes under same growth conditions. It showed that Bt genotypes can help in maintaining soil macronutrients (total nitrogen, available phosphorus, and available potassium) under proper nutrient management. Moreover, Bt-cotton genotypes seem to strengthen certain biological properties of the soil, thus increasing the growth and yield capability, maintaining available nutrients in the soil as compared to non-Bt cotton, while no harmful effects of Bt cotton on soil properties was detected.