| Popis: |
Crassulacean acid metabolism (CAM) is one of three major models of carbon dioxide assimilation pathway with better water-use efficiency and slower photosynthetic efficiency inphotosynthesis. Previous studies indicated that overexpressing the plant ferredoxin-like protein (PFLP) cloned from sweet pepper can enhance disease resistance to bacterial pathogens and boost photosynthesis rate in C3 and C4 plants, but not for CAM. The protein sequence of PFLP shows high homology to the ferredoxin-1(Fd-1) family that belongs to photosynthetic type Fd and involves in photosystem I. It is speculated that overexpressing pflp in the CAM plant may enhance photosynthetic efficiency through the electron transport chain (ETC). In this report, pflp transgenic Phalaenopsis were generated to reveal the effects of overexpressing PFLP in CAM photosynthetic efficiency with several photosynthetic features. For the electron transport rate (ETR), the transgenic pflp plants exhibited by 1.2-folds than those of wild type (WT).The efficiency of the photosynthetic electron transport chain (PETC) was 1.7-folds due to the quantum efficiency of linear electron flow (LEF) elevated in transgenic pflp plants. Higher CO2 assimilation rates were observed up to 1.6 and 1.5-folds sampled at 4 pm and10 pm respectively. In the Phase III of CAM, the enzyme activity of phosphoenolpyruvate carboxylase (PEPC) was increased by 5.9-folds, and in the Phase IV, NAD+-linked malic enzyme (NAD+-ME) activity was increased by 1.4-folds in transgenic pflp plants. For the evaluation of photosynthesis products, the carbohydrate levels were analyzed. Soluble sugars contents such as glucose, fructose, and sucrose were increased significantly by 1.2, 1.8, and 1.3-folds higher in transgenic pflp plants. The starch grains were also accumulated up to 1.4-folds. These results indicated that overexpressing pflp in transgenic CAM plants can increase carbohydrates accumulation by enhancing electron transport flow during photosynthesis. Taken altogether, we suggested that pflp is an potential gene for agriculture application that not only increases disease resistance but also enhances electron transport chain efficiency during photosynthesis. |
