Articles

Many agriculturally important properties such as heterosis, inbreeding depression, phenotypic plasticity, and resistance for biotic and abiotic stresses are thought to be affected with epigenetic components. New discoveries related with epigenetics are likely to have a major impact on strategies for crop improvement in rice breeding. However, assessing the contribution of epigenetics to heritable variation in plant species still poses major challenges. Methylation of cytosine in DNA is one of the most important epigenetic mechanisms in plants. DNA methylation not only plays significant roles in the regulation of gene activity, but also it is related with genomic integrity. Although most of next generation sequencing (NGS) technologies do not require the use of target specific primer pairs to identify and study DNA cytosine methylation, validation studies of NGS uses selective primer pairs. Bisulfite sequencing technique is a gold method for DNA cytosine methylation studies. However, bisulfite sequencing requires the development of bisulfite primer pairs to selectively study DNA sequences of interest. In this study 9 bisulfite specific primer pairs were identified and validated. These primer pairs successfully amplified bisulfite converted and unconverted genomic DNA extracted from radicle and plumule of rice (Oryza sativa L.) seedlings. Results of the present study clearly revealed the occurrence of CG, CHG and CHH (H stands for C. T or A nucleotides) contents in studied DNA sequence targets were different indicating potential role of DNA cytosine methylation in these genes. Primer pairs reported in this study could be used to detect DNA methylation which is one of the most important epigenetic mechanisms affecting the development, differentiation or the response to biotic and abiotic stress in rice (Oryza sativa L.).

This study purposed to study the Preservative agents that are required to ensure that manufactured foods remain safe and unspoiled; work was conducted to evaluate the efficacy of essential oils from two eucalyptus species, Eucalyptus grandis and Eucalyptus crebra in food preservatives; to run this experiment flesh eucalyptus leaves collected from Ruhande Arboretum forest were submitted to hydrodistillation and yields(amount) of 0.38 and 0.34 % for Eucalyptus grandis and Eucalyptus crebra were obtained, respectively. Phaseolus vulgaris, Sorghum condatum, cooked Ipomoea batatas (sweet potatoes) and bread were the sample foods used to assess their preservative efficacy. Acanthoscelides obtectus and Stophilus oryzae were used as pests for Phaseolus vulgaris and Sorghum condatum respectively. For bread and cooked Ipomoea batatas, Rhizopus nigricans are used to assess the efficacy of these two essential oils to inhibit their growth; the obtained results revealed that those essential oils could act as insecticide in the storage of Phaseolus vulgaris and Sorghum condatum. Essential oil from Eucalyptus grandis protected these two foods against pests in the periods of 4 and 9 days, respectively while essential oil from Eucalyptus crebra protected them for the periods of 6 and 11days, respectively.

Aflatoxins, produced by Aspergillus spp., are strongly toxic and carcinogenic fungal secondary metabolites. Aflatoxin biosynthesis is a complex process and involves at least 30 genes clustered within an approximately 75 kB gene cluster. In this paper, we reviewed current status of the researches on the characterized structural genes involved in aflatoxin biosynthesis and their roles in aflatoxin-producing fungi, especially in A. flavus and A. parasiticus, which will improve our understanding of the mechanism of aflatoxin biosynthesis and regulation and provide reference for further study.

The halophyte Distichlis palmeri (Vasey) is a plant resource with high potential to be harvested in the coastal areas of northwestern Mexico; enlarge the knowledge and domestication for its incursion into the agricultural sector, plays an important role for arid areas with saline intrusion problems. However, its productivity depends on the supplementary supply of nitrogen, as well as other essential macro and micronutrients. The microorganisms considered beneficial are an alternative to chemical fertilization, highlighting those Plant Growth Promoting Bacteria (PGPB). In the present study, the inoculation of the Bacillus amyloliquefaciens (B.a.) as a halobacterium PGPB was evaluated to know the response in seeds of Distichlis spicatai obtained from natural population from colorado river in Delta north of the Gulf of California. Wild seed was collected and germinated previously inoculated with B. a., and sowed in germinated beds. Later, seedlings were planted under field and salinity conditions in the coast of Hermosillo, Sonora. Three treatments were examined (T1: B.a., T2: Chemical fertilization, T3: Negative control), with four repetitions each treatment. Each repetition consisted of experimental plots of 5 x 5 m, with a separation of 1 m between them. The harvest was carried out 600 days after sowing. The results indicate that treatments inoculated with halobacteria B.a., showed significant results in crude protein, non-protein nitrogen, neutral detergent fiber and acid detergent fiber, as well as spike length and number of seeds. The results obtained suggests the feasibility of biofertilizers where biomass and seed production are significant compared to non-inoculated controls.

The armored scale Aulacaspis alisiana, is a serious invasive pest of the Japanese silver tree, Neolitsea sericea, causing serious damage to the tree in Japan. However there are currently no control approaches available for it, complicated by shortage of information on the pest. We studied life history strategies of A. alisiana on N. sericea in Fukuoka Prefecture with a view to providing a basis for formulating sustainable control based on an understanding of the behavior of the pest and potential role of its natural enemies. We established that A. alisiana had three overlapped generations in Fukuoka, with generation times ranging between 65 and 71 days. The adults were relatively fecund, with each female producing between 60 and 67 eggs, with high hatchability, >78%. The pest settled on the lower side of leaves, and although it generally preferred younger leaves, it did not attack newly emerged leaves. Natural enemy groups comprising ants, spiders and beetles (coccinelids) played an important role in regulation of the pest population, with natural mortality of about 30%. They could thus form a critical component of an integrated management approach for the pest in Fukuoka.

Phytosanitary inspectors play an important role in diagnosing diseases in foreign plant material. However, some deficiencies have been detected in the detectionc ausing the entrance of many microorganisms. Therefore, it was of great interest to detect the presence of Clavibacter michiganensis subsp. michiganensis (Cmm) in foreign tomato and chili seed in the agricultural area of Sinaloa, Mexico, besides the growth and cell density of Cmm was evaluated in different selective media under continuous illumination and photoperiod. The results indicate that seeed of 35 varieties of tomatoes was collected; while for Chili seed were 18. This study was supported by farmers (225) which represent 79% of all growers and 32 business engaged in the sale of agro-supplies, provided seeds of varieties and hybrids. Those growers are from six areas (Culiacan, El Tamarindo, Navolato, Culiacan, El dorado and Badiraguato). For detection of Cmm in tomato seed, from 35, only four was variability considering Immunochromatography and ELISA techniques; however, considering chemical and physiological test, the result was negative. Similar results were in 18 varietes of chili seed, where eight showed variability to detect Cmm, and negative by chemical and physiological test. According to the growth and cell density of Cmm, the optimal medium was YDC under pH stable and continuous light conditions. It is recommended to consider the fusion of diagnostic techniques in the emission of a result.

Diseases are a major cause of post-harvest losses depending on season, region and management practices. Chemical control is the most used but with serious consequences for human health and the environment. This forces us to carry out more exhaustive studies on botanical products. The general objective of the present study was to evaluate the effect of citrus extracts for the control of pathogens that cause post-harvest diseases in tomato fruit. The product to be evaluated is of botanical origin from citrus extracts. Doses were evaluated (0, 666, 1000, 2000, 4000, 8000 ppm). The treatments were located at a temperature of 25°C±2 and 45% relative humidity (rH). The design used corresponded to a completely random design. The least significant difference was estimated by Tukey Multiple Range test at P=0.05. The statistical tests were performed through the SAS computer program. The results indicate that the pathogens detected and identified correspond to Alternaria tenuissima; Botrytis cinerea; Cladosporium fulvum; Colletotrichum coccodes; Fusarium oxysporum; Geotrichum candidum; Rhizopus stolonifer and Stemphylium macrosporoideum. Our conclusion is that the efficient doses correspond to 666, 2000 and 8000 ppm. With the application of citrus extracts, the damage percentage of tomato fruit was reduced in relation to the control treatments. Based on the results with the application of citrus extracts, the shelf life of the tomato was lengthened.

In this work we used semi-isolated heart of the cockroach Nauphoeta cinerea for the investigation of the pharmacological effects of extracts (aqueous, 1:1, 1:2, 1:4 and 1:8) from Nephrolepis exaltata L. leaves, a popular ornamental fern considered to be safe. The use of insects in experimental studies has grown due to the easy handling, proliferation/growing assuring its rapid obtention, and absence of ethical issues. An aqueous extract 0.2 % was obtained after maceration of 1 g N. exaltata leaves powder with 20 mL of distilled water (1:20). Diluted extracts in water were obtained to have the following proportion 1:1, 1:2, 1:4 and 1:8. Experiments (n=4) consisted of 200 µL addition onto semi-isolated heart preparation of N. cinerea with concomitant heart beating counting. Aqueous, 1:1 and 1:2 extracts paralyzed completely the heart beatings of cockroachs (p<0.05 compared to saline control), but not 1:4 or 1:8, which showed only a slight decline (p>0.05 compared to saline control). A preliminary thin layer chromatography showed the presence of unidentified terpenoid in aqueous extract of N. exaltata. These pharmacological findings of N. exaltata can be exploited for future use as insecticide or as dose-dependently cholinergic agent.

Ubiquitination is a kind of posttranslational modification of proteins in eukaryotes, and it plays an important role in the growth and development of organisms. The ubiquitination of proteins is a cascade enzymatic reaction involving three enzymes. The homologous to E6-AP carboxy terminus ubiquitin-protein ligases (HECT E3s) family is an important ubiquitin-protein ligases family. The family all have a HECT domain of approximately 350 amino acids in the C-terminus. However, studies on plant HECT E3s, such as structural features, prediction of HECT domain function, and their regulatory mechanisms, are very limited. In this paper, Arabidopsis thaliana HECT family genes were analyzed, including gene structure and functional domains and its limited known functions in protein degradation, gene transcription regulation, epigenetically regulation or other functions, finally speculate their roles in plant morphologies, aging or responsive to environmental stress.

Psidium guajava (guava) is an important crop and economic resource in many tropical countries and Brazil stands out as one of its major commercial producers. The guava crop has been severely attacked by the plant parasitic nematode Meloidogyne enterolobii which has caused drastic reduction of productivity and, in some cases, even total loss of cultivated areas. The use of resistant rootstocks that are tolerant to these soil pathogens can be a low-cost solution to this pathogen, which has established itself as one of the major constraints for the cultivation of guava in Northeast Brazil. The objective of this work was to evaluate the reaction of P. guajava and P. guineense to M. enterolobii infection under greenhouse conditions, with an infection period of 60 days. 12 P. guineense, and 4 P. guajava were evaluated. The host response to the nematode infection was evaluated according to the following parameters: gill index (GI), reproductive factor (RF), and reduction of reproductive factor (RRF). Considering the RRF criteria, the P. guineense genotypes, AR1, AR3, AR4 and AR10 were considered resistant. The RF index was considered inadequate to evaluate resistance in the 60 days period, due the slow development of the parasite in P.guineense.