RESUMO
Drought is a pivotal cause for crop yield reductions. When subjected to recurrent external stimuli, plants can develop memory of stress responses that, eventually, enables improved plant tolerance to environmental changes. In addition, despite causal relationships, these responses may vary according to hierarchical levels of observation. Thus, this study aims to check the responses of recurrent and non-recurrent stresses in two rice genotypes observing their drought memory responses at different levels of organization, that is, on a physiological, biochemical and metabolomic scale and for end in global PCA. For this, seventy variables were measured on the scales described in order to obtain a large number of observations. The memory responses were evident in almost all scales observed. The lowland genotype, especially plants not subjected to recurrent water shortage, showed higher damage to the photosynthetic apparatus under drought conditions, although it has exhibited more evident memory response effect after rehydration. On the other hand, the upland genotype appears to be more tolerant to drought insofar lower biochemical damage was observed. Specific behaviors of each genotype at biochemical and metabolomics levels and similar behavior at physiological level were observed. This study demonstrates the importance of observation at different hierarchical levels.
Assuntos
Adaptação Fisiológica/genética , Desidratação/genética , Desidratação/fisiopatologia , Secas , Oryza/genética , Oryza/fisiologia , Água/metabolismo , Brasil , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Variação Genética , Genótipo , Estresse Fisiológico/genéticaRESUMO
Combination of biotic and abiotic stress is a major challenge for crop and fruit production. Thus, identification of genes involved in cross-response to abiotic and biotic stress is of great importance for breeding superior genotypes. Lectins are glycan-binding proteins with a functions in the developmental processes as well as in the response to biotic and abiotic stress. In this work, a lectin like gene, namely ClLectin1, was characterized in Volkamer lemon and its expression was studied in plants exposed to either water stress, hormonal elicitors (JA, SA, ABA) or wounding to understand whether this gene may have a function in the response to multiple stress combination. Results showed that ClLectin1 has 100% homology with a L-type lectin gene from C. sinensis and the in silico study of the 5'UTR region showed the presence of cis-responsive elements to SA, DRE2 and ABA. ClLectin1 was rapidly induced by hormonal treatments and wounding, at local and systemic levels, suggesting an involvement in defence signalling pathways and a possible role as fast detection biomarker of biotic stress. On the other hand, the induction of ClLectin1 by water stress pointed out a role of the gene in the response to drought. The simultaneous response of ClLectin1 expression to water stress and SA treatment could be further investigated to assess whether a moderate drought stress may be useful to improve citrus performance by stimulating the SA-dependent response to biotic stress.