Search

Tomato chlorosis virus (ToCV) is a whitefly-transmitted crinivirus that causes yield losses, mainly in tomato (Solanum lycopersicum) and potato (S. tuberosum) crops. In this work, a polyclonal antiserum for detecting the virus using a dot-blot immunoassay was developed and the responses of crinivirus-infected potato genotypes were evaluated. The virus was purified using infected tomato leaves and the antiserum was obtained by intramuscular injection of purified viral preparations in rabbit. Tomato and potato tissue samples were used to validate the polyclonal antiserum for detection of ToCV, previously analyzed by RT-PCR. A total of 81 tomato and potato samples were analyzed by RT-PCR and dot-blot immunoassay (DBIA). All samples were positive in RT-PCR, but three of them did not react in DBIA, showing of 96.3% efficiency compared with that in RT-PCR. All potato genotypes inoculated with ToCV by Bemisia tabaci MEAM1 were susceptible to infection. Potato plants of cv. Camila infected by ToCV showed the lowest virus titer and were asymptomatic.

Cocoa beans used for chocolate production are fermented seeds of Theobroma cacao obtained by a natural fermentation process. The flavors and chemical compounds produced during the fermentation process make this step one of the most important in fine chocolate production. Herein, an integrative analysis of the variation of microbial community structure, using a shotgun metagenomics approach and associated physicochemical features, was performed during fermentation of fine cocoa beans. Samples of Forastero variety (FOR) and a mixture of two hybrids (PS1319 and CCN51) (MIX) from Bahia, Brazil, were analyzed at 7 different times. In the beginning (0 h), the structures of microbial communities were very different between FOR and MIX, reflecting the original plant-associated microbiomes. The highest change in microbial community structures occurred at the first 24 h of fermentation, with a marked increase in temperature and acetic acid concentration, and pH decrease. At 24–48 h both microbial community structures were quite homogenous regarding temperature, acetic acid, succinic acid, pH, soluble proteins and total phenols. During 72–96 h, the community structure resembles an acidic and warmer environment, prevailing few acetic acid bacteria. Taxonomic richness and abundance at 72–144 h exhibited significant correlation with temperature, reducing sugars, succinic, and acetic acids. Finally, we recommend that dominant microbial species of spontaneous fine cocoa fermentations should be considered as inoculum in accordance with the farm/region and GMP to maintain a differential organoleptic feature for production of fine chocolate. In our study, a starter inoculum composed of Acetobacter pausterianus and Hanseniaspora opuntiae strains is indicated.

Made available in DSpace on 2020-12-12T00:58:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-08-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) The golden mosaic (begomovirus) and the yellowing (crinivirus) diseases are among the main viral diseases occurring in solanaceous crops in Brazil. A survey of viruses associated with both diseases was conducted on cultivated solanaceous plants from 2013 to 2017 to study their diversity and distribution in the Southeast/Midwest regions of Brazil. Samples from potato, eggplant, sweet pepper and tomato plants were collected in fields of seven Brazilian states (Bahia, Espírito Santo, Goiás, Minas Gerais, Paraná, Rio de Janeiro and São Paulo) and in the Federal District. Total RNA/DNA was extracted and tested by RT-PCR/PCR to detect the crinivirus tomato chlorosis virus (ToCV) and begomoviruses, respectively. Representative amplicons were directly sequenced for virus identification. Out of 343 samples, 54 were positive for ToCV: 38.6% in potato, 0.9% in sweet pepper, and 20.9% in tomato. For begomovirus detection, 234 samples were positive. In potato and sweet pepper plants, only tomato severe rugose virus (ToSRV) was detected, while four begomoviruses were detected in tomato plants. ToSRV was detected in 80.1% of the tomato samples, and was the predominant begomovirus. These results indicate a low diversity of crinivirus and begomovirus species infecting cultivated solanaceous crops in Brazil during the survey period. ESALQ/USP UNESP/FCA INCAPER Embrapa Vegetables Centro de Ensino Unificado de Brasília – CEUB UNESP/FCA FAPESP: 2012/51771-4

Repeated measures are widely used in a variety of aspects related to plant research, such as the assessment of genotypes subjected to stressing agents. Analysis of variance is routinely employed in split-plot experimental designs with repeated measurements on the subplots. However, this is not the best approach, as measurements cannot be randomly taken and so the H-F condition is rarely met. In this study, procedures of multivariate analysis of profiles (MAP) are presented as statistically advantageous options for solving similar analytical problems. We used data from trials with 10 clonal genotypes of cacao (Theobroma cacao) in which their seedlings’ resistance against ceratocystis wilt was assessed on 11 repeated measures that did not comply with the H-F condition. Multivariate analyses based on the disease-response profiles of all clones allowed us to understand the genotype-specific patterns of disease growth, identify when profiles reached the plateau, verify the levels of damage at this point, and a...

The main achievement of this work was an attempt to determine the best association between five tropical species and light environments, based on the physiological and morphological characters related to photosynthesis. Information about light tolerance and photosynthetic plasticity of indigenous tropical tree species is still limited, particularly information of first years of plants’ development. In this study, we evaluated the adjustments in response to different light environments of 25 leaf traits most commonly assessed in studies on light acclimation of photosynthesis in current literature. This evaluation was used to investigate the photosynthetic plasticity on young plants of five tropical tree species belonged to different successional groups. All the species are commonly used in forest restoration programs in Brazil. Plants were grown for 6 months under different light conditions simulating environments that could exist due to variation in naturally occurring canopy openings of secondary tropical forests. The level of adjustment on leaf traits to environmental conditions was calculated via a plasticity index. The relation between leaf trait adjustments and species photosynthetic plasticity was investigated by multivariate Biplot analyses. We selected the seven most explicative leaf traits of the photosynthetic plasticity of the studied species in response to different light environments: dark respiration rate (R d), Rubisco carboxylation capacity (V cmax), total chlorophyll content (ChlT), contribution of spongy parenchyma (%SP), contribution of leaf collenchyma tissue (%C), chlorophyll parenchyma thickness (PP/SP) and specific leaf area (SLA). Based on the selected traits, we identified the traits most related to high plasticity (V cmax, PP/SP, %SP, %C and SLA) and low plasticity (V cmax, R d and ChlT) and grouped species into three different patterns of photosynthetic plasticity. Our plasticity grouping was not correlated with species successional classification, indicating the importance of including physiological features related to light tolerance in species successional classifications. This work provides complementing information to traditional species successional groupings and to our current ability to select species for enrichment planting on restoration efforts.

Mudas de progênies de polinização livre de 20 clones de cacaueiro (Theobroma cacao) foram inoculadas com o fungo Ceratocystis cacaofunesta, agente causal da murcha-de-Ceratocystis, e a resposta avaliada pelo percentual de plantas mortas. Progênies de polinização aberta dos clones TSH1188 e VB1151 foram usadas como padrões de resistência, e de CCN51 e SJ02 como suscetíveis. Foram estimados contrastes entre estes referenciais e as progênies em estudo, e avaliados pelo teste t de Dunnett (α= 0,05). As progênies apresentaram diferentes respostas a C. cacaofunesta sendo possível classificá-las em três grupos: resistente (FCB01, CSG70, BOBA01, VB902, TSH1188, VB1151, PS1319 e MAC01), moderadamente suscetível (HW25, PM02, FA13, PH15, M05 e BJ11) e suscetível (CCN51, FB206, PH16, SJ02, CCN10 e FSU77). Seedlings from open-pollinated progenies of 20 clones of cocoa (Theobroma cacao) were inoculated with the fungus Ceratocystis cacaofunesta, the causal agent of Ceratocystis wilt, and their response was assessed based on the percentage of dead plants. Open pollinated progeny of clones TSH1188 and VB1151 were used as standards for resistance, while CCN51 and SJ02 for susceptibility. Contrasts between these benchmarks and the progenies studied were estimated and evaluated by Dunnett's t test (α= 0.05). The progenies showed different responses to C. cacaofunesta, and it was possible to classify them into three groups: resistant (FCB01, CSG70, BOBA01, VB902, TSH1188, VB1151, PS1319 and MAC01), moderately susceptible (HW25, PM02, FA13, PH15, M05 and BJ11) and susceptible (CCN51, FB206, PH16, SJ02, CCN10 and FSU77).

Resistance of fourteen Theobroma cacao clones to Phytophthora spp. was evaluated using stem inoculations on grafted seedlings. Concepts of phenotypic stability were used to interpret the results and to express horizontality of the resistance. The linear regression coefficient 'b', the determination coefficient (R²) and average lesion size were used to determine the level of horizontal resistance, the phenotypic stability and the predictability of all clones. The results indicated that clones P 7 and MA 15 present highest levels of horizontal resistance and stability, but with moderate predictability. Clones CAS 1 and CEPEC 13 were classified as those with high horizontal resistance, stability and predictability, while clones PA 30, UF 650 and SIAL 88 and EET 59 showed intermediate resistance and stability and high predictability. Clones SPA 17, OC 61, PA 150, SIAL 505, ICS 1 and R 41 presented high susceptibility and intermediate or low stability and moderate or high predictability.