2023-02-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/653216溫室氣體(CO2, CH4, and N2O)造成的全球氣候變遷已在近年來影響了台灣的農業發 展，其中被譽為台灣綠金的大豆種植易受其害。大豆具有互利共生的固氮細菌，故 可藉由固氮作用將氮氣(N2) 轉化成硝酸氮(NO3-)及銨(NH4+)，作為植物養分來源。 然有研究指出在大豆生長後期根瘤老化時，過多的NO3-及NH4+若不能藉由反硝化作用 中的N2O還原酶(nosZ基因)轉化成N2，則將造成更多的N2O逸散至大氣中。因此大豆根 瘤的健康與nosZ基因表現量，牽動著種植大豆的N2O釋放量。大豆紅冠腐病為近年來 在高屏地區嚴重發生的土媒性病害，然而土壤中存在的病原菌是否負面影響大豆根 瘤的N2O還原酶表現，目前尚無研究。本研究計畫擬評估土壤中存在紅冠腐病菌 (Calonectria ilicicola)的情況下，是否對大豆根瘤的N2O還原酶表現量有負面影 響，進而造成根瘤的N2O含量上升。實驗擬添購N2O微電極測量系統直接定量根瘤內 N2O濃度，並搭配RT-qPCR定量固氮關鍵基因(nifH)與nosZ基因之表現量，整合定量 結果以評估土壤中存在紅冠腐病菌對於N2O含量之影響。如實驗結果支持假說，則將 說明防治土媒性病害的重要性不僅於植物保護，更可避免大豆根瘤在病原菌壓力下 產出較高含量的N2O，以達成農業淨零排放之永續目標。 Global climate change caused by greenhouse gases (CO2, CH4, and N2O) has affected agricultural industry of Taiwan in recent years, and the production of soybean, which is known as the green gold of Taiwan, is also vulnerable to climate change. Soybean has mutually beneficial rhizobacteria, which perform nitrogen fixation to convert nitrogen gas (N2) into nitrate (NO3-) and ammonium (NH4+) that both serve as N sources of plants. However, some studies have shown for scenescent soybean nodules, if excessive NO3- and NH4+ cannot be converted into N2 by N2O reductase (nosZ gene) in the last step of denitrification, more N2O will be released into the atmosphere. Therefore, the health of soybean nodules and the expression of nosZ gene affect the N2O abundance released from soybean. Soybean red crown rot (RCR) is a severe soil-borne disease in the Kaohsiung-Pingtung region in recent years. However, whether the presence of RCR fungus (Calonectria ilicicola) in soils would negatively affect the N2O reductase in soybean nodules remains unclear. This research project intends to assess whether the presence of C. ilicicola in soil increases N2O production by reducing nosZ expression in soybean nodules. This proposal intends to purchase the N2O microelectrode measurement system to directly quantify the N2O concentration in nodules, and apply RT-qPCR to quantify the expression of nitrogen fixation key gene (nifH) and nosZ gene. The integration of both quantitative results would evaluate the impact of C. ilicicola on N2O production. If the hypothesis can be supported, this research will demonstrate the importance of managing soil-borne diseases is not only for plant protection, but also for prevention of N2O production under the biotic stress of soil-borne pathogens. Collectively, the novelty and achievement oin this research will support the sustainable goal of net zero emissions in agriculture.氧化亞氮;氧化亞氮還原酶基因;大豆;紅冠腐病;溫室氣體;根瘤;Nitrous oxide (N2O);N2O reductase gene (nosZ);Soybean (Glycine max);red crown rot;Calonectria ilicicola;Greenhouse gas;Nodule