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
The interaction between water-soluble CdS and gelatin 5n aqueous solution was explored using fluorescence,infrared (IR)and UV-Vis spectra at pH 12.0 and different temperatures.Results show that the formed complex had a strong ability to quench the fluorescence launched from gelatin.The fluorescence quenching data were analvzed according to Lineweave-Burk double-reciprocal equation and the gelatin had reacted with CdS to form a complex.This kind of static fluorescence quenching goes with non-radiation energy transfer happening within single molecule According to Lineweave-Burk equation,K(285 K:1.07×10~4 L/mol;292 K:9 69×10~3 L/mol;299 K:8.06×10~3 L/mol),the formation constants of the compound at different temperatures and the thermodynamic parameters(△H=-14.18 kJ/mol;△G=-21.98/-22.28/-22.36 kJ/mol;△S=27.36/27.74/27.36 J/K·mol) at certain temperatures were obtained,indicating that the binding force between them is mainly the static in nature.The binding locality was an area of 4.09 nm away from tryptophan residue in gelatin based on F(o)rster's non-radiation energy transfer mechanism.The results provide information for exploring the chemical mechanism of interaction between nanoparticle and this kind of biological macromolecule.