RESUMO
KEY MESSAGE: Overexpression of StCaM2 in tobacco promotes plant growth and confers increased salinity and drought tolerance by enhancing the photosynthetic efficiency, ROS scavenging, and recovery from membrane injury. Calmodulins (CaMs) are important Ca2+ sensors that interact with effector proteins and drive a network of signal transduction pathways involved in regulating the growth and developmental pattern of plants under stress. Herein, using in silico analysis, we identified 17 CaM isoforms (StCaM) in potato. Expression profiling revealed different temporal and spatial expression patterns of these genes, which were modulated under abiotic stress. Among the identified StCaM genes, StCaM2 was found to have the largest number of abiotic stress responsive promoter elements. In addition, StCaM2 was upregulated in response to some of the selected abiotic stress in potato tissues. Overexpression of StCaM2 in transgenic tobacco plants enhanced their tolerance to salinity and drought stress. Accumulation of reactive oxygen species was remarkably decreased in transgenic lines compared to that in wild type plants. Chlorophyll a fluorescence analysis suggested better performance of photosystem II in transgenic plants under stress compared to that in wild type plants. The increase in salinity stress tolerance in StCaM2-overexpressing plants was also associated with a favorable K+/Na+ ratio. The enhanced tolerance to abiotic stresses correlated with the increase in the activities of anti-oxidative enzymes in transgenic tobacco plants. Overall, our results suggest that StCaM2 can be a novel candidate for conferring salt and drought tolerance in plants.
Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Secas , Nicotiana/genética , Nicotiana/fisiologia , Proteínas de Plantas/metabolismo , Salinidade , Solanum tuberosum/metabolismo , Estresse Fisiológico , Antioxidantes/metabolismo , Proteínas de Ligação ao Cálcio/genética , Calmodulina/genética , Calmodulina/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Genoma de Planta , Germinação/efeitos dos fármacos , Germinação/genética , Íons , Membranas , Fotossíntese/efeitos dos fármacos , Reguladores de Crescimento de Plantas/farmacologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Prolina/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Sequências Reguladoras de Ácido Nucleico/genética , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/crescimento & desenvolvimento , Estresse Fisiológico/efeitos dos fármacos , Estresse Fisiológico/genética , Nicotiana/enzimologia , Nicotiana/crescimento & desenvolvimento , Fatores de Transcrição/metabolismo , Água/metabolismoRESUMO
Selenium (Se) is a vital mineral for both plants and animals. It is widely distributed on the earth's crust and is taken up by the plants as selenite or selenate. Plants substantially vary in their physiological response to Se. The amount of Se in edible plants is genetically controlled. Its availability can be determined by measuring its phytoavailability in soil. The low concentration of Se in plants can help them in combating stress, whereas higher concentrations can be detrimental to plant health and in most cases it is toxic. Thus, solving the double-edged sword problem of nutritional Se deficiency and its elevated concentrations in environment requires a better understanding of Se uptake and metabolism in plants. The studies on Se uptake and metabolism can help in genetic biofortification of Se in plants and also assist in phytoremediation. Moreover, Se uptake and transport, especially biochemical pathways of assimilation and incorporation into proteins, offers striking mechanisms of toxicity and tolerance. These developments have led to a revival of Se research in higher plants with significant break throughs being made in the previous years. This review explores the new dimensions of Se research with major emphasis on key research events related to Se undertaken in last few years. Further, we also discussed future possibilities in Se research for crop improvement.