本文選題：溶磷能力　切入點：pqqE　出處：《西北農林科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：在農業(yè)生產中磷的需求量只低于氮,在自然條件下,可被吸收利用的可溶性磷經常是限制農業(yè)生產的一類礦質營養(yǎng)。內生細菌Pseudomonas sp.GZJR-8分離于拐棗七的莖部,初步鑒定其具有顯著溶磷作用。本研究鑒定了GZJR-8的pqqE和GDH基因在溶磷方面的功能;利用同源重組技術分別獲得pqqE和GDH基因的缺失突變體,采用電轉法獲得它們的互補菌株;采用難溶性無機磷培養(yǎng)基(PKO)和抗壞血酸-鉬藍顯色定磷法分別定性和定量檢測了野生型、突變體、互補菌株是否產生溶磷圈以及產生有效磷的總量和培養(yǎng)液的pH;結果表明:pqqE和GDH基因是GZJR-8的溶磷相關基因,其中突變體的溶磷能力下降,但并未完全喪失溶磷能力,而互補菌株可以恢復溶磷能力;該菌株通過產生酸性物質來溶磷;能夠促進植物生長;該菌株在農業(yè)生產方面具有潛在應用價值。本研究從駱駝刺的葉和莖部分離得到兩個菌株LTYR-11和LTJR-57,16S rRNA基因序列測定與系統(tǒng)發(fā)育分析,發(fā)現(xiàn)這兩株菌分別隸屬Bosea屬和Blastococcus屬,親緣關系最近的模式菌株分別為Bosea vaviloviae Vaf-18T(95%)和Blastococcus saxobsidens BC448T(98.8%)。與已知模式菌株較低的序列相似性暗示這兩株菌可能是潛在新分類單元。隨后,本研究檢測了這2株內生菌的培養(yǎng)條件、生長溫度、生長pH、耐鹽性、抑菌活性、多種酶活、產鐵載體等生理生化指標;結果表明:Bosea sp.LTYR-11的最適生長條件是0.1TSA和NA培養(yǎng)基;30-37℃生長良好,44℃不能生長;最適pH為7.5-8;在NaCl濃度0-1%時生長良好、在1.5%NaCl不生長;不能在厭氧環(huán)境下生長;可以泳動;具有產鐵載體能力;具有過氧化氫酶、脲酶活性。Blastococcus sp.LTJR-57的最適生長條件是MA培養(yǎng)基;37-44℃生長良好,25℃以下和50℃以上停止生長;能在pH9的堿性條件下生長;在NaCl含量為0%時生長良好、當NaCl濃度大于4%時不能生長;有產鐵載體能力;能降解脫脂奶(酪蛋白)和酪氨酸;具有過氧化氫酶和脲酶活性。
[Abstract]:The demand for phosphorus in agricultural production is only lower than that of nitrogen. Under natural conditions, soluble phosphorus that can be absorbed and utilized is often a mineral nutrient that restricts agricultural production. Pseudomonas sp.GZJR-8, an endophytic bacterium, is isolated from the stem of Jujube. In this study, the functions of pqqE and GDH genes of GZJR-8 in phosphorus solubilization were identified, the deletion mutants of pqqE and GDH genes were obtained by homologous recombination technique, and their complementary strains were obtained by electroporation. Wild type and mutants were detected qualitatively and quantitatively by insoluble inorganic phosphorus medium (PKO) and ascorbic acid-molybdenum blue colorimetric method. The results showed that the pqqE and GDH genes were the phosphorus-soluble related genes of GZJR-8, and the phosphorus-soluble ability of the mutants was decreased, but the phosphorus-soluble ability of the mutants was not completely lost. The complementary strain can restore phosphorus solubilizing ability, it can dissolve phosphorus by producing acid substance, it can promote plant growth. In this study, two strains of LTYR-11 and LTJR-57716S rRNA gene were isolated from the leaves and stems of Camellia spp. The results showed that the two strains belonged to Bosea genus and Blastococcus genus, respectively. The most closely related model strains were Bosea vaviloviae Vaf-18Tf95) and Blastococcus saxobsidens BC448T988, respectively. The low sequence similarity with known model strains suggested that the two strains might be potential new taxa. Subsequently, the culture conditions of the two endophytic bacteria were examined. Growth temperature, pH, salt tolerance, bacteriostatic activity, enzyme activity, iron production carrier and other physiological and biochemical indexes, the results showed that the optimum growth conditions of sp.LTYR-11 were 0.1TSA and Na medium 30-37 鈩，

本文編號：1584584