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In this study, the effects were investigated of salinity, foliar and soil applications of humic substances on the growth and mineral nutrients uptake of Corn (Hagein, Fardy10), and the comparison was carried out of the soil and foliar applications of humic acid treatments at different NaCl levels. Soil organic contents are one of the most important parts that they directly affect the soil fertility and textures with their complex and heterogenous structures although they occupy a minor percentage of the soil weight. Humic acids are an important soil component that can improve nutrient availability and impact on other important chemical, biological, and physical properties of soils. The effects of foliar and soil applications of humic substances on the plant growth and some nutrient elements uptake of Corn (Hagein, Fardy10) grown at various salt concentrations were examined. Sodium chloride was added to the soil to obtain 20 and 60mM saline conditions. Solid humus was applied to the soil one month before planting and liquid humic acids were sprayed on the leaves twice on 20th and 40th day after seedling emergence. The application doses of solid humus were 0, 2 and 4 g/kg and those of liquid humic acids were 0, 0.1 and 0.2%. Salinity negatively affected the growth of corn; it also decreased the dry weight and the uptake of nutrient elements except for Na and Mn. Soil application of humus increased the N uptake of corn while foliar application of humic acids increased the uptake of P, K, Mg,Na,Cu and Zn. Although the effect of interaction between salt and soil humus application was found statistically significant, the interaction effect between salt and foliar humic acids treatment was not found significant. Under salt stress, the first doses of both soil and foliar application of humic substances increased the uptake of nutrients.

Effect of polyamines on the reduction of hexavalent chromium by bacterial strains and their resistance. Polyamines are involved in several functions in bacteria. In this study, we examined the role of polyamines in hexavalent chromium (Cr[VI]) reduction by three bacterial strains isolated from sites contaminated by tannery effluents. The strains were identified as Serratia proteamaculans, Leucobacter chromiireducens and Brevibacterium frigoritolerans. The inhibition of polyamine synthesis by α-difluoromethylornithine (DFMO) caused a decrease in Cr(VI) tolerance in the bacterial isolates, indicating the role of endogenous polyamines in resistance to Cr(VI). The exogenous application of polyamines (putrescine, spermidine, cadaverine) was found to stimulate growth and Cr(VI) reduction by the bacterial strains in Luria-Bertani medium. The results show the importance of polyamines in response to heavy metal stresses, especially Cr(VI) toxicity.

Fusarium wilt of bananas (also known as Panama disease), caused by the soil-borne fungus Fusarium oxysporum f. sp cubense (Foc), is a serious problem to banana production worldwide. Genetic resistance offers the most promising means to the control of Fusarium wilt of bananas. In this study, the inheritance of resistance in Musa to Foc race 1 was investigated in three F₂ populations derived from a cross between ‘Sukali Ndizi’ and ‘TMB2X8075-7’. A total of 163 F₂ progenies were evaluated for their response to Fusarium wilt in a screen house experiment. One hundred and fifteen progenies were susceptible and 48 were resistant. Mendelian segregation analysis for susceptible versus resistant progenies fits the segregation ratio of 3:1 (χ² = 1.72, P = 0.81), suggesting that resistance to Fusarium wilt in Musa is conditioned by a single recessive gene. We propose panama disease 1 to be the name of the recessive gene conditioning resistance to Fusarium wilt in the diploid banana ‘TMB2X8075-7’.

Introduction. Insect-plant interactions are affected directly or indirectly by stress factors. The effect of environmental resource availability on insect-plant interactions is here reviewed. Subsequently, the analysis focuses on aphid-host plant interactions, particularly in the system composed by the green peach aphid Myzus persicae and its primary host plant Prunus persica. Literature. Plant defenses arise in two ways: resistance and tolerance, both are affected by abiotic factors. The information gathered from studies (n = 29) on plant-aphid interactions addressing the reduction in water availability on plant resistance, showed that in 41,4% of the studies, drought stress elicits lower resistance, while 34.5%, 20.1% and 3.4%, showed higher, no change and conditional effects on plant resistance, respectively. Conclusions. Water stress elicits mixed effects on plant resistance to aphids. However, the literature review also suggests that cultural practices play a role in the fate of the peach-aphid interactions, whereas the development of predictive models aimed to assist crop-pest management systems still requires more basic information. Aphid responses to plant defenses under stressed conditions are still largely unexplored. © 2016, FAC UNIV SCIENCES AGRONOMIQUES GEMBLOUX. All rights reserved.

Some effects of dietary medicinal herbs mixture (HM), Massa medicata fermentata, Crataegi fructus, Artemisia capillaries, and Cnidium officinale, in the proportions 2:2:1:1 were identified in juvenile Japanese flounder Paralichthys olivaceus. In an 8‐week feeding trial, fish were fed with 0.1, 0.3, 0.5, and 1.0% HM in a moist diet composed of horse mackerel and an artificial diet in equal parts. Fish fed the diets with 0.3, 0.5, and 1.0% HM showed higher weight gain and feed efficiency than fish in 0.1 and 0% HM feed groups. No significant differences were found in survival, feed intake, final carcass proximate composition, hemoglobin and hematocrit levels, plasma total cholesterol level, and alanine aminotransferase activity among the dietary treatments. Fish fed with 0.3, 0.5, and 1.0% HM showed higher total carcass unsaturated fatty acid content and docosahexaenoic acid (22:6n‐3) level, and plasma high density lipoprotein‐cholesterol level, but lower carcass saturated fatty acid content and plasma aspartate aminotrasferase activities than the control group. Moreover, a 10‐min air exposure test with five times repeat, and an anesthesia test for 2 min with 200 p.p.m. 2‐phenoxyethanol, also revealed lower mortality and lower recovery time in 0.3, 0.5, and 1.0% HM groups than the control group at the end of the trial. These results indicate that the medicinal herb mixture is useful to improve growth, fatty acid utilization, and stress recovery in the Japanese flounder.

A collection of 250 enterococci isolated from various food-stuffs were used to investigate seven virulence determinants and the microbial susceptibility of eight antibiotics. Species-specific PCR revealed the presence of E. faecalis (127 isolates), E. faecium (77 isolates), E. casseliflavus (21 isolates), E. mundtii (19 isolates) and E. durans (6 isolates). Multiplex PCR for virulence factors showed that out of the 250 isolates tested, 221 carried one or more virulence-encoding genes. Beta-haemolytic activity was also evident in enterococcal species other than E. faecalis and E. faecium. Species other than E. faecalis and E. faecium isolated from food may also be virulent. Antimicrobial susceptibility was tested using the disk diffusion method. It showed that out of 250 isolates, 114 were resistant to cephalothin and 94 to ofloxacin. Lower antibiotic resistance was seen with ampicillin, chloramphenicol, gentamicin and teicoplanin. None of the isolates was found to be resistant to vancomycin. The results of this study show that food can play an important role in the spread of virulent enterococci through the food chain.

We examined the ability of yellow poplar ( Liriodendron tulipifera ) tissue cultures and plantlets to express modified mercuric reductase ( merA ) gene constructs. Mercury-resistant bacteria express merA to convert highly toxic, ionic mercury, Hg(ll), to much less toxic, elemental mercury, Hg(O). Expression of merA in transgenic plants might provide an ecologically compatible approach for the remediation of mercury pollution. Because the alteration of the bacterial merA gene sequence is necessary for high-level expression in Arabidopsis thaliana , yellow poplar proembryogenic masses (PEMs) were transformed with three modified merA constructs via microprojectile bombardment. Each construct was synthesized to have altered flanking regions with increasing amounts of modified coding sequence. All merA constructs conferred resistance to toxic, ionic mercury in independently transformed PEM colonies. Stability of merA transgene expression increased in parallel with the extent of gene coding sequence modification. Regenerated plantlets containing the most modified merA gene ( merA18 ) germinated and grew vigorously in media containing normally toxic levels of ionic mercury. The merA18 plantlets released elemental mercury at approximately 10 times the rate of untransformed plantlets. These results indicate that plants expressing modified merA constructs may provide a means for the phytoremediation of mercury pollution.

Introduction. Insect-plant interactions are affected directly or indirectly by stress factors. The effect of environmental resource availability on insect-plant interactions is here reviewed. Subsequently, the analysis focuses on aphid-host plant interactions, particularly in the system composed by the green peach aphid Myzus persicae and its primary host plant Prunus persica. Literature. Plant defenses arise in two ways: resistance and tolerance, both are affected by abiotic factors. The information gathered from studies (n = 29) on plant-aphid interactions addressing the reduction in water availability on plant resistance, showed that in 41,4% of the studies, drought stress elicits lower resistance, while 34.5%, 20.1% and 3.4%, showed higher, no change and conditional effects on plant resistance, respectively. Conclusions. Water stress elicits mixed effects on plant resistance to aphids. However, the literature review also suggests that cultural practices play a role in the fate of the peach-aphid interactions, whereas the development of predictive models aimed to assist crop-pest management systems still requires more basic information. Aphid responses to plant defenses under stressed conditions are still largely unexplored. La complexité des interactions insectes-plantes en fonction de différents niveaux de ressources et de résistance de l’hôte : le cas de Myzus persicae-Prunus persica (synthèse bibliographique) Introduction. Les interactions plantes-insectes sont influencées directement ou indirectement par plusieurs facteurs de stress. Dans cette synthèse bibliographique, l’effet de la disponibilité des ressources sur ces interactions est en premier lieu abordé au sens large, suivi d’une analyse ciblée des relations impliquant le modèle puceron, en particulier le puceron vert du pêcher Myzus persicae et son hôte principal, Prunus persica. Littérature. Les défenses des plantes envers les insectes se manifestent de deux façons : la résistance et la tolérance, toutes deux influencées par des facteurs abiotiques. Les informations recueillies à partir d’études (n = 29) concernant l'effet de la diminution de la disponibilité en eau sur les défenses contre les insectes, ont montré que dans 41,4 % des études, le stress hydrique induit la résistance. Dans 34,5 %, 20,1 % et 3,4 %, les effets sur la résistance étaient respectivement moindres, absents et conditionnels. Conclusions. Le stress hydrique provoque des effets mitigés sur la résistance des plantes aux pucerons. Toutefois, la revue bibliographique suggère également un rôle des pratiques culturales dans les interactions pêcher-puceron, tandis que le développement de modèles prédictifs visant à assister les systèmes de gestion des bio-agresseurs nécessite la collecte de davantage de données.

Pests, diseases and weeds (biotic stresses) are significant limiting factors for crop yield and production. However, the limitations associated with conventional breeding methods necessitated the development of alternative methods for improving new varieties with higher resistance to biotic stresses. Molecular techniques have developed applicable methods for genetic transformation of a wide range of plants. Genetic engineering approach has been demonstrated to provide enormous options for the selection of the resistance genes from different sources to introduce them into plants to provide resistance against different biotic stresses. In this review, we focus on strategies to achieve the above mentioned objectives including expression of insecticidal, antifungal, antibacterial, antiviral resistance and herbicide detoxification for herbicide resistance. Regardless of the concerns about commercialization of products from genetically modified (GM) crops resistant to biotic stresses, it is observed that the cultivation area of these crops is growing fast each year. Considering this trend, it is expected that production and commercialization of GM crops resistant to biotic stresses will continue to increase but will also extend to production of crops resistant to abiotic stresses (e.g. drought, salinity, etc.) in a near future.