RESUMO
Although heterosis has significantly contributed to increases in worldwide crop production, the molecular mechanisms regulating this phenomenon are still unknown. In the present study, we used a comparative proteomic approach to explore hybrid vigor via the proteome of both the popcorn L54 â and P8 â genotypes and the resultant UENF/UEM01 hybrid cross. To analyze the differentially abundant proteins involved in heterosis, we used the primary roots of these genotypes to analyze growth parameters and extract proteins. The results of the growth parameter analysis showed that the mid- and best-parent heterosis were positive for root length and root dry matter but negative for root fresh matter, seedling fresh matter, and protein content. The comparative proteomic analysis identified 1343 proteins in the primary roots of hybrid UENF/UEM01 and its parental lines; 220 proteins were differentially regulated in terms of protein abundance. The mass spectrometry proteomic data are available via ProteomeXchange with identifier "PXD009436". A total of 62 regulated proteins were classified as nonadditive, of which 53.2% were classified as high parent abundance (+), 17.8% as above-high parent abundance (+ +), 16.1% as below-low parent abundance (- -), and 12.9% as low parent abundance (-). A total of 22 biological processes were associated with nonadditive proteins; processes involving translation, ribosome biogenesis, and energy-related metabolism represented 45.2% of the nonadditive proteins. Our results suggest that heterosis in the popcorn hybrid UENF/UEM01 at an early stage of plant development is associated with an up-regulation of proteins related to synthesis and energy metabolism.
Assuntos
Quimera , Vigor Híbrido/fisiologia , Proteínas de Plantas , Raízes de Plantas , Proteoma , Plântula , Zea mays , Quimera/genética , Quimera/crescimento & desenvolvimento , Metabolismo Energético/genética , Regulação da Expressão Gênica de Plantas/genética , Proteínas de Plantas/biossíntese , Proteínas de Plantas/genética , Raízes de Plantas/genética , Raízes de Plantas/crescimento & desenvolvimento , Proteoma/biossíntese , Proteoma/genética , Plântula/genética , Plântula/crescimento & desenvolvimento , Regulação para Cima/genética , Zea mays/genética , Zea mays/crescimento & desenvolvimentoRESUMO
Apple bitter rot (ABR) and Glomerella leaf spot (GLS) can be caused by Colletotrichum fructicola. Although both diseases can occur simultaneously in orchards, some isolates show clear organ specialization. Thus, this work was aimed to compare microscopically the development of preinfective structures of ABR- and GLS isolates and their impact on the enzymatic oxidant defense system during the leaf infection process. On leaves, conidial germlings of GLS-isolate formed appressoria mostly sessile. In contrast, those of ABR-isolate were pedicellate and formed multiple melanized appressoria probably as a sign of unsuccessful infection attempts. Neither ABR- nor GLS isolate triggered hypersensitive response in apple leaves. In overall, the activity of scavenging enzymes was higher and long-lasting in leaves inoculated by GLS- than by ABR isolate and control. Guaiacol peroxidase, catalase, and glutathione reductase had activity peaks within 24 h after inoculation (HAI). Ascorbate peroxidase activity was higher only in GLS-infected leaves at 6 HAI, while superoxide dismutase remained unaltered. A lower level of hydrogen peroxide (H2O2) was determined in GLS-infected plants at 48 HAI, but the electrolyte leakage markedly increased. Disease symptoms in leaves were only caused by GLS-isolate. Results suggest that the virulent isolate coordinately downregulates the oxidative plant defense responses enabling its successful establishment in apple leaves.
Assuntos
Colletotrichum/isolamento & purificação , Malus/microbiologia , Doenças das Plantas/microbiologia , Colletotrichum/genética , Colletotrichum/crescimento & desenvolvimento , Colletotrichum/metabolismo , Peróxido de Hidrogênio , Malus/enzimologia , Malus/genética , Malus/metabolismo , Estresse Oxidativo , Peroxidase/genética , Peroxidase/metabolismo , Doenças das Plantas/genética , Folhas de Planta/enzimologia , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/microbiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Esporos Fúngicos/classificação , Esporos Fúngicos/genética , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/isolamento & purificação , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismoRESUMO
Colletotrichum fructicola is the main species causing apple bitter rot (ABR) and Glomerella leaf spot (GLS) in southern Brazil, and ABR in Uruguay where GLS remains unnoticed. Thus, this work aimed to determine the genetic structure of C. fructicola isolates of both the countries. A total of 28 out of 31 Brazilian isolates (90.3%) caused typical symptoms of GLS, while only 6 of 25 Uruguayan isolates (24.0%) originating from fruits were able to infect leaves, but causing atypical symptoms. Both populations showed similar levels of Nei's gene diversity (h = 0.088 and 0.079, for Brazilian and Uruguayan populations, respectively), and Bayesian cluster analysis inferred two genetic clusters correlated with the geographical origin of isolates. A principal coordinates analysis scatter plot and an unweighted pair group method with arithmetic mean-based dendrogram also grouped Brazilian and Uruguayan isolates into two groups. By pairwise comparison of nitrate-nonutilizing (nit) mutants with a proposed set of testers, all Uruguayan isolates were grouped into a unique vegetative compatibility group (namely VCG 1), while Brazilian isolates were grouped into four VCGs (VCG 1 to 4). Brazilian and Uruguayan populations of C. fructicola were found to be genetically distinct. Our results suggest that isolates of C. fructicola from Brazil capable of causing GLS and ABR arose independently of those from Uruguay. Possible causes leading to the evolutionary differences between populations are discussed.
