O papel dos fitocromos B nas respostas ao estresse induzido pela deficiência de NPK em tomateiro
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Data
2022-04-08
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Universidade Estadual Paulista (Unesp)
Resumo
A luz é o sinal ambiental que influencia o crescimento e desenvolvimento das plantas, desde a germinação ao florescimento. As plantas percebem, interpretam e traduzem os sinais luminosos por meio dos fotorreceptores, entre eles os fitocromos, que absorvem comprimentos de onda do vermelho ao vermelho extremo e controlam diversas respostas no ciclo de vida das plantas, incluindo a nutrição. Tem se tornado cada vez mais evidente a participação desse fotorreceptor nas respostas das plantas ao estresse causado pela deficiência nutricional. Entretanto, embora haja algumas evidências na literatura, ainda é pouco conhecida a interação dos fitocromos B com os mecanismos de respostas ao estresse por deficiência de nitrogênio (N), fósforo (P) e potássio (K), que são os nutrientes considerados mais responsivos pelas plantas. Essa pesquisa foi realizada com o objetivo de estudar o papel dos fitocromos B nas respostas nutricionais, fisiológicas e de crescimento do tomateiro ao estresse por deficiência de N, P e K. Inicialmente, plantas dos mutantes com perda de função de phyB1 (phyB1) e phyB2 (phyB2) e do seu genótipo controle (Solanum lycopersicum L. cv Moneymaker) foram cultivadas sob deficiência de N, P e K. A deficiência de phyB1 e phyB2 diminuiu o acúmulo de N, P e K, a concentração de clorofilas e carotenoides e a produção de massa seca das plantas sob suficiência nutricional. Em plantas deficientes em N, phyB1 regula positivamente a absorção de N, a síntese de pigmentos e produção de massa seca, enquanto apenas a absorção de N está sob controle de phyB2. A deficiência de phyB1 mitigou os danos causados pela deficiência de P, pois aumentou a produção de massa seca das plantas em relação ao genótipo controle. Sob deficiência de K, phyB1 aumenta a absorção de P e síntese de clorofilas e carotenoides e phyB2 diminui a peroxidação lipídica das membranas. Posteriormente, a fim de avaliar se o controle de phyB1 nas respostas do tomateiro a deficiência de N, P e K ocorre reciprocamente a partir da comunicação entre parte aérea e raiz, foram utilizados enxertos recíprocos e combinações de enxertia entre phyB1 e o genótipo controle sob condições de deficiência de N, P e K. O fitocromo B1 da parte aérea está envolvido na absorção de N e P e regula positivamente a condutância estomática e transpiração do tomateiro. A utilização do genótipo controle como enxerto e phyB1 como porta-enxerto aliviou os danos causados pela deficiência de N, evidenciado pelo aumento na massa seca. Esses resultados sugerem que o controle das respostas nutricionais, fisiológicas e de crescimento do tomateiro é realizado pelos fitocromos através da comunicação entre parte aérea e raiz.
It is already well known that light is an environmental signal that influences the growth and development of plants from germination to flowering. Plants perceive, interpret, and translate light signals through a complex system of photoreceptors, including phytochromes, which absorb wavelengths from red to far red and control several responses in the life cycle of plants, including nutrition. The participation of this photoreceptor in plant responses to stress caused by nutritional deficiency has become increasingly evident. However, although there is some evidence in the literature, little is known about the interaction of phytochromes B (phyB) with the mechanisms of stress responses due to nitrogen (N), phosphorus (P) and potassium (K) deficiency, which are the nutrients considered most responsive by plants. This research was carried out with the objective of studying the role of phytochromes B in the nutritional, physiological and growth responses of tomato to N, P, and K deficiency. Initially, phyB1 and phyB2 tomato mutants (deficient in phyB1 and phyB2) and their control genotype (Solanum lycopersicum L. cv Moneymaker) were cultivated under sufficiency and N, P and K deficiency. In N-deficient plants, phyB1 upregulates N uptake, pigment synthesis and dry weight production, while only N uptake is under the control of phyB2. phyB1 deficiency mitigated the damage caused by P deficiency, as it increased the plant dry weight production in relation to the control genotype. Under K deficiency, phyB1 increased P uptake, chlorophyll, and carotenoid synthesis and phyB2 decreases membrane lipid peroxidation. Afterwards, to verify whether the interaction between phyB1 and N, P, and K occurs reciprocally to the communication between shoots and roots; reciprocal grafts and graft combinations between the control genotype and phyB1 were used under nutritional sufficiency and individual deficiencies of N, P, and K. It was verified that shoot phytochrome B1 is involved in the absorption of N and P and regulates stomatal conductance and transpiration of tomato. The grafting combination between the control genotype as scion and phyB1 as rootstock alleviated the damages of nitrogen deficiency by increasing dry weight production. These results suggest that the control of nutritional, physiological and growth responses of tomato is performed by phytochrome through shoot-root communication.
It is already well known that light is an environmental signal that influences the growth and development of plants from germination to flowering. Plants perceive, interpret, and translate light signals through a complex system of photoreceptors, including phytochromes, which absorb wavelengths from red to far red and control several responses in the life cycle of plants, including nutrition. The participation of this photoreceptor in plant responses to stress caused by nutritional deficiency has become increasingly evident. However, although there is some evidence in the literature, little is known about the interaction of phytochromes B (phyB) with the mechanisms of stress responses due to nitrogen (N), phosphorus (P) and potassium (K) deficiency, which are the nutrients considered most responsive by plants. This research was carried out with the objective of studying the role of phytochromes B in the nutritional, physiological and growth responses of tomato to N, P, and K deficiency. Initially, phyB1 and phyB2 tomato mutants (deficient in phyB1 and phyB2) and their control genotype (Solanum lycopersicum L. cv Moneymaker) were cultivated under sufficiency and N, P and K deficiency. In N-deficient plants, phyB1 upregulates N uptake, pigment synthesis and dry weight production, while only N uptake is under the control of phyB2. phyB1 deficiency mitigated the damage caused by P deficiency, as it increased the plant dry weight production in relation to the control genotype. Under K deficiency, phyB1 increased P uptake, chlorophyll, and carotenoid synthesis and phyB2 decreases membrane lipid peroxidation. Afterwards, to verify whether the interaction between phyB1 and N, P, and K occurs reciprocally to the communication between shoots and roots; reciprocal grafts and graft combinations between the control genotype and phyB1 were used under nutritional sufficiency and individual deficiencies of N, P, and K. It was verified that shoot phytochrome B1 is involved in the absorption of N and P and regulates stomatal conductance and transpiration of tomato. The grafting combination between the control genotype as scion and phyB1 as rootstock alleviated the damages of nitrogen deficiency by increasing dry weight production. These results suggest that the control of nutritional, physiological and growth responses of tomato is performed by phytochrome through shoot-root communication.
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Solanum lycopersicum L., Deficiência nutricional, phyB, Nutritional deficiency, Fitocromo, Nutrientes