ABSTRACT
ACC oxidase (ACO) is one of the key enzymes that catalyze the synthesis of ethylene. Ethylene is involved in salt stress response in plants, and salt stress seriously affects the yield of peanut. In this study, AhACO genes were cloned and their functions were investigated with the aim to explore the biological function of AhACOs in salt stress response, and to provide genetic resources for the breeding of salt-tolerant varieties of peanut. AhACO1 and AhACO2 were amplified from the cDNA of salt-tolerant peanut mutant M29, respectively, and cloned into the plant expression vector pCAMBIA super1300. The recombinant plasmid was transformed into Huayu22 by pollen tube injection mediated by Agrobacterium tumefaciens. After harvest, the small slice cotyledon was separated from the kernel, and the positive seeds were screened by PCR. The expression of AhACO genes was analyzed by qRT-PCR, and the ethylene release was detected by capillary column gas chromatography. Transgenic seeds were sowed and then irrigated with NaCl solution, and the phenotypic changes of 21-day-seedings were recorded. The results showed that the growth of transgenic plants were better than that of the control group Huayu 22 upon salt stress, and the relative content of chlorophyll SPAD value and net photosynthetic rate (Pn) of transgenic peanuts were higher than those of the control group. In addition, the ethylene production of AhACO1 and AhACO2 transgenic plants were 2.79 and 1.87 times higher than that of control peanut, respectively. These results showed that AhACO1 and AhACO2 could significantly improve the salt stress tolerance of transgenic peanut.
Subject(s)
Salt Tolerance/genetics , Arachis/genetics , Plant Breeding , Ethylenes/metabolism , Plants, Genetically Modified/genetics , Gene Expression Regulation, Plant , Plant Proteins/geneticsABSTRACT
Este trabalho teve por objetivo avaliar a interferência da madeira utilizada na construção das caixas, denominadas de bins, utilizadas no armazenamento comercial, sobre a eficiência da aplicação de doses de 1-metilciclopropeno (1-MCP) em maçãs da cultivar Royal Gala. Os tratamentos avaliados foram: controle (sem 1-MCP e sem madeira); 1-MCP (625nL L-1); 1-MCP (625nL L-1) + madeira de eucalipto (Eucaliptus sp); 1-MCP (625nL L-1) + madeira de cedrinho (Erisma uncinatum Warm); 1-MCP (1.250nL L 1); 1-MCP (1.250nL L-1) + eucalipto e 1-MCP (1.250nL L-1) + cedrinho. Após quatro meses de armazenamento a 0,5°C mais sete dias a 20°C, não foi observada diminuição da qualidade dos frutos tratados com 1-MCP e armazenados na presença e ausência de madeira, evidenciando que as madeiras de eucalipto e cedrinho não absorvem o 1-MCP a ponto de influenciar a eficiência do produto. A atividade da ACC oxidase, a síntese de etileno, a respiração, a firmeza da polpa e a cor da epiderme não diferiram entre as maçãs tratadas com 1-MCP e armazenadas na presença ou não de madeira. Também não houve diferença entre as doses de 1.250nL L-1 e 625nL L-1 de 1-MCP na maturação dos frutos. Conclui-se que os dois tipos de madeira utilizados na construção das embalagens e que são utilizados para o armazenamento de maçãs em câmaras frigoríficas comerciais não interferiram na eficiência de 1-MCP sobre a maturação dos frutos.
This research aimed to evaluate the interference of the wood used in the boxes building, which the name are bins, used in the commercial storage, under the 1-metylcyclopropene (1-MCP) doses efficiency applied in 'Royal Gala' apples. The evaluated treatments were: control (without 1-MCP and without wood); 1-MCP (625nL L-1); 1-MCP (625nL L-1) + eucalyptus wood (Eucaliptus sp); 1-MCP (625nL L-1) + cedrinho wood (Erisma uncinatum Warm); 1-MCP (1.250nL L-1); 1-MCP (1.250nL L-1) + eucalyptus wood and 1-MCP (1.250nL L-1) + cedrinho wood. After four months of cold storage at 0,5°C and more seven days at 20°C, there was no decrease in the fruits quality that were treated with 1-MCP and stored on the presence and absence of wood, which showed that eucalyptus and cedrinho wood don't absorb 1-MCP to the point of influencing the product efficiency. The activity of the ACC oxidase, ethylene synthesis, respiration, flesh firmness and skin color didn't differ among the apples treated with 1-MCP and stored in the presence or absence of wood used in the bins building. There also was no difference among the doses of 1.250nL L-1 and 625nL L-1 1-MCP in the fruit maturation. In conclusion, the two kinds of wood used in the boxes building, which are used for the apple storage in commercial cold storage chambers, doesn't interfere in the efficiency of 1-MCP in apple maturation.
ABSTRACT
Este trabalho teve por objetivo avaliar o efeito da inibição da biossíntese de etileno no período pré-colheita e o efeito da inibição da ação ou da absorção do etileno durante o armazenamento em atmosfera controlada (AC; 1,2kPa de O2 + 2,5kPa de CO2 a 0ºC) sobre a qualidade de maçãs cv. "Gala". Além disso, avaliou-se também o efeito combinado desses tratamentos. Os tratamentos avaliados foram: (1) armazenamento em AC (controle); (2) aplicação pré-colheita de AVG; (3) AVG + aplicação pós-colheita de 1-MCP; (4) aplicação de 1-MCP; (5) AVG + absorção do etileno durante todo o período de armazenamento; e (6) absorção de etileno. Após oito meses de armazenamento mais sete dias a 20ºC, os frutos tratados com AVG apresentaram menor atividade da ACC oxidase. A combinação de AVG + 1-MCP ou AVG + absorção de etileno mantiveram menor produção de etileno até cinco dias de vida de prateleira a 20ºC. Além disso, a firmeza da polpa dos frutos submetidos a esses tratamentos combinados manteve-se mais elevada. A cor de fundo da epiderme manteve-se mais verde nos frutos tratados com AVG, independente do tratamento em pós-colheita, demonstrando que a modificação da coloração da epiderme é mais afetada pelo etileno produzido ainda na pré-colheita. Portanto, conclui-se que a aplicação em pré-colheita de AVG associada com a absorção do etileno durante o armazenamento é mais eficiente no controle da maturação de maçãs "Gala", no entanto, a aplicação pré-colheita de AVG combinada com a aplicação pós-colheita de 1-MCP também é eficiente.
This research aimed to evaluate the effect of inhibition the ethylene biosynthesis at the pre-harvest stage, the ethylene action and the absorption from the controlled atmosphere storage room on the quality of 'Gala' apples. The experimental design was entirely randomized, with four replicates and the experimental unit composed by 25 fruits. The treatments were: (1) CA storage only (control); (2) pre-harvest application of AVG; (3) AVG + postharvest treatment with 1-MCP; (4) 1-MCP; (5) AVG + ethylene absorption during the storage period; and (6) ethylene absorption. Fruit quality was evaluated after 8 months of storage (CA; 1.2 kPa O2 + 2.5 kPa CO2 at 0ºC) and after 7 days at 20ºC. AVG-treated fruits showed lower ACC oxidase activity. AVG + 1-MCP and AVG + ethylene absorption decreased the ethylene production until 5 days of shelf-life and maintained higher flesh firmness. AVG-treated fruits had greener skin color, independently of the postharvest handling, showing that the change in the skin background colour is highly related to the pre-harvest ethylene production. The conclusion of this research is that the pre-harvest treatment of fruits with AVG associated with the absorption of ethylene during the storage is more efficient for controlling the ripening process in 'Gala' apples, nevertheless the application of AVG associated with postharvest application of 1-MCP is also efficient.