Organic practices intensify the microbiome assembly and suppress root-knot nematodes

Journal of Pest Science - Roots can recruit beneficial microorganisms to suppress plant pathogens. However, conventional and organic practices differently shape the soil microbiome and consequently...     

Colletotrichum gloeosporioides, a new causal agent of citrus post-bloom fruit drop

Citrus post-bloom fruit drop (caused by Colletotrichum acutatum) frequently occurs in the southwestern region of São Paulo State, Brazil. A survey of Colletotrichum isolates associated with symptoms of post-bloom fruit drop in São Paulo State showed C. gloeosporioides in addition to C. acutatum. The objectives of this study were to confirm the identification of C. gloeosporioides isolated from symptomatic citrus flowers, to test the pathogenicity of C. gloeosporioides isolates, to compare the development of disease caused by C. gloeosporioides and C. acutatum, and to determine the frequency of C. gloeosporioides in a sample of isolates obtained from symptomatic flowers in different regions of São Paulo State. Through the use of species-specific primers by PCR, 17.3% of 139 isolates were C. gloeosporioides, and the remaining 82.7% were C. acutatum. The pathogenicity tests, carried out in 3-year old potted plants of sweet oranges indicated that both species caused typical symptoms of the disease including blossom blight and persistent calyces. Incubation periods (3.5 and 3.9 days, respectively, for C. acutatum and C. gloeosporioides) and fruit sets (6.7 and 8.5%, respectively for C. acutatum and C. gloeosporioides) were similar for both species. The incidences of blossom blight and persistent calyces were higher on plants inoculated with C. acutatum than in those inoculated with C. gloeosporioides. Conidial germination was similar for both species under different temperatures and wetness periods. Under optimal conditions, appressorium formation and melanisation were higher for C. gloeosporioides than for C. acutatum. These results indicated that Colletotrichum gloeosporioides is a new causal agent of post-bloom fruit drop.     

甘蔗作为能源作物的优势分析及前景展望

与其他能源作物相比,能源甘蔗在原料供应、乙醇产量、生产成本及加工技术等方面具有明显优势,发展前景广阔。能源乙醇生产有利于蔗糖产业的持续发展,促进农业产业结构调整,稳定和提高农民收入。当前,发展甘蔗燃料乙醇产业应重视解决品种选育、工艺改进、政策扶持等问题。     

High inoculum of Monilinia fructicola is a threat to peach production in the tropics due to fruit susceptibility at all development stages

Brown rot is the main disease of stone fruits in Brazil, but the susceptibility of peaches to brown rot at different stages of development in the field has not been studied under subtropical conditions. This information is relevant to guide the management of the disease. The objective of this research was to determine the influence of inoculating peaches with Monilinia fructicola at different stages of development on the infection and progress of brown rot at postharvest. Two experiments were carried out: one ex vivo with two cultivars and the other in the field for two seasons. Peaches were inoculated at different sizes for both experiments. In the field, peaches were bagged to avoid natural infection, and M. fructicola inoculum was monitored. The ex vivo incidence of the disease was lower at pit hardening than at other fruit stages for both cultivars. The incidence of brown rot for peaches attached to the trees increased with fruit ripening. Conversely, the time for symptom expression was reduced according to peach diameter. Peaches inoculated with a diameter smaller than 2 cm showed a lower incidence of brown rot and longer periods for disease expression than fruit inoculated near harvest. In conclusion, in areas with high inoculum in the orchard, a common condition in the subtropics, the grower must prevent infection at all stages of fruit development, thus avoiding losses during marketing.     

耐氨固氮菌对黄瓜种子萌发、幼苗素质和保护酶活性的影响

采用耐氨固氮菌浸种处理黄瓜种子.结果表明,用2%菌液浸处理黄瓜种子,黄瓜种子发芽势、幼苗素质及子叶保护酶活性均有显著提高,幼苗子叶抗氧化功能增强,其中以浸种时间为3、4 h的效果尤为明显.     

Influence of the extracting solvent upon the structural properties of Amaranth (Amaranthus hypochondriacus) glutelin

Two amaranth glutelin preparations, Gt-bo extracted with borate buffer at pH 10 and Gt-na extracted with 0.1 N NaOH, were characterized and compared with the amaranth polymerized 11S globulin (Gp, globulin-P). Gt-bo and Gt-na presented very similar polypeptidic composition and a similar reactivity against an anti-Gp polyclonal antibody, although lower than that of Gp. It is demonstrated that Gt-na is composed of denatured and dissociated molecules, whereas Gt-bo consists of folded molecules. The size, polypeptidic composition, thermal stability, and denaturation enthalpy of Gt-bo molecules were similar to those of Gp subjected to a borate treatment at pH 10. The Gp immunoreactivity decreased to the level of Gt reactivity when subjected to alkaline treatment; this could be due to conformational changes. Results suggest that, like Gp, amaranth Gt molecules may be hexameric oligomers of approximately 300 kDa. They would be partially unfolded during the alkaline extraction.     

Soil Fertility,Nutrition and Early Growth of Physic Nut as Affected by Nitrogen Fertilization

The initial growth and mineral nutrition of the physic nut (Jatropha curcas L.) as a function of nitrogen (N) fertilization was investigated. The transplanting of seedlings was carried out in plastic pots filled with 50 dm³ of a Rhodic Hapludox, under a plastic greenhouse. In addition to a control treatment, the dosages of 0, 40, 80, 120, and 160 mg dm^?3 N were tested. The results demonstrated that N fertilization for the cultivation of physic nut could be added as top dressing from 60 days after planting with a dosage of 65 mg dm^?3. A SPAD index of 46 can be used as a nutritional reference to its initial development. Furthermore, the results suggested that the order of nutrient accumulation by the physic nut plants is as follows: potassium (K) > N > magnesium (Mg) > calcium (Ca) > phosphorus (P) > sulfur (S) > iron (Fe) > manganese (Mn) > boron (B) > zinc (Zn) > copper (Cu).     

Distribution of herbicides in soil in a simulated drip irrigation system

Summary The behavior of two herbicides (bromacil and napropamide) applied to a Mediterranean red loam soil (hamra) from a point source is presented. Neither herbicide was degraded during the period of the study. Bromacil was only slightly adsorbed by the soil (K _d – 0.1 ml/g; Fig. 1) and was evenly distributed in the soil volume when applied at a constant concentration (Fig. 3). The distribution of napropamide, which was adsorbed by the soil (K _d – 1.2 ml/g; Fig. 1), was restricted to the zone immediately around the emitter (Fig. 3). Application of the herbicides to previously wetted soils increased the vertical and lateral movement of both herbicides (Fig. 4). Leaching of the chemicals was more pronounced for bromacil than for napropamide (Fig. 5). Cycles of irrigation and evaporation at two irrigation frequencies demonstrated that bromacil can be leached quickly from the emitter zone whereas naproparnide will move only slowly into the soil volume (Fig. 8).Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 289-E, 1980 Series     

Intra-city Differences in Cardiac Expression of Inflammatory Genes and Inflammasomes in Young Urbanites: A Pilot Study

Southwest Mexico City (SWMC) air pollution is characterized by high concentrations of ozone and particulate matter < 10 μm (PM(10)) containing lipopolysaccharides while in the North PM(2.5) is high. These intra-city differences are likely accounting for higher CD14 and IL-1β in SWMC v NMC mice myocardial expression. This pilot study was designed to investigate whether similar intra-city differences exist in the levels of myocardial inflammatory genes in young people. Inflammatory mediator genes and inflammasome arrays were measured in right and left autopsy ventricles of 6 southwest/15 north (18.5 ± 2.6 years) MC residents after fatal sudden accidental deaths. There was a significant S v N right ventricle up-regulation of IL-1β (p=0.008), TNF-α (p=0.001), IL-10 (p=0.001), and CD14 (p=0.002), and a left ventricle difference in TNF-α (p=0.007), and IL-10 (p=0.02). SW right ventricles had significant up-regulation of NLRC1, NLRP3 and of 29/84 inflammasome genes, including NOD factors and caspases. There was significant degranulation of mast cells both in myocardium and epicardial nerve fibers. Differential expression of key inflammatory myocardial genes and inflammasomes are influenced by the location of residence. Myocardial inflammation and inflammasome activation in young hearts is a plausible pathway of heart injury in urbanites and adverse effects on the cardiovascular system are expected.