焦子偉,張相鋒,張 娜,吾爾恩,郭巖彬
(1. 伊犁師范學(xué)院化學(xué)與生物科學(xué)學(xué)院,新疆伊寧 835000;2. 中國(guó)農(nóng)業(yè)大學(xué)資源與環(huán)境學(xué)院,北京 100193)
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不同碳源條件下PQQ對(duì)植物促生菌RahnellaaquatilisHX2溶解無機(jī)磷影響的研究
焦子偉1,張相鋒1,張 娜1,吾爾恩1,郭巖彬2
(1. 伊犁師范學(xué)院化學(xué)與生物科學(xué)學(xué)院,新疆伊寧835000;2. 中國(guó)農(nóng)業(yè)大學(xué)資源與環(huán)境學(xué)院,北京100193)
摘要:【目的】水生拉恩氏菌(Rahnella aquatilis)HX2能合成葡萄糖脫氫酶(glucose dehydrogenase, GDH)和吡咯喹啉醌(pyrroloquinoline quinone,PQQ),PQQ為GDH輔酶,與其共同參與葡萄糖溶磷代謝。揭示不同碳源條件下PQQ影響HX2菌株溶解無機(jī)磷作用的機(jī)理?!痉椒ā恳砸吧闔X2、突變體MH15及其互補(bǔ)菌株CMH15(pqq)為供試材料,在不同碳源條件下采用平板溶磷、鉬銻抗比色法等方法對(duì)其進(jìn)行溶解無機(jī)磷定性、定量以及pH相關(guān)分析?!窘Y(jié)果】除D-山犁醇、D-果糖外,PQQ參與HX2菌株對(duì)木糖、葡萄糖、D-甘露糖、D-甘露醇、蔗糖、乳糖6種碳源的溶磷代謝,但其溶磷代謝因HX2菌株利用不同碳源的能力而不同,以乳糖利用最低,木糖利用最高。【結(jié)論】PQQ作為GDH的輔酶,兩者共同參與HX2菌株的木糖、葡萄糖、D-甘露糖、D-甘露醇、蔗糖和乳糖溶解無機(jī)磷代謝,并起到重要調(diào)控作用。
關(guān)鍵詞:吡咯喹啉醌;水生拉恩氏菌HX2;不同碳源;無機(jī)磷
0 引 言
【研究意義】RahnellaaquatilisHX2菌株已作為優(yōu)良的溶磷促生菌應(yīng)用于伊犁河谷綠色有機(jī)農(nóng)業(yè)生產(chǎn)中[1],進(jìn)一步明確其溶磷機(jī)理可對(duì)其促進(jìn)植物生長(zhǎng)提供理論依據(jù)和技術(shù)支持?!厩叭搜芯窟M(jìn)展】 HX2菌株具有較強(qiáng)的溶磷能力,可利用不同碳源的培養(yǎng)基生長(zhǎng),產(chǎn)生PQQ和GDH,PQQ作為GDH的輔酶,兩者共同參與其葡萄糖溶磷代謝[2]。焦子偉等[1]已明確在不同碳源溶磷培養(yǎng)基條件下,GDH參與了HX2菌株對(duì)木糖、萄萄糖、D-甘露糖、D-甘露醇、乳糖、蔗糖、D-果糖D-山梨醇溶磷代謝。【本研究切入點(diǎn)】Guo等[3]已通過Tn5插入突變pqq基因獲得了突變菌株MH15,以及其互補(bǔ)菌株CMH15(pqq)。研究在已有基礎(chǔ)上,采用平板溶磷、鉬銻抗比色法等實(shí)驗(yàn)方法,分析研究不同碳源下PQQ對(duì)HX2菌株溶解無機(jī)磷能力的影響。【擬解決的關(guān)鍵問題】明確PQQ在不同碳源下對(duì)HX2菌株溶磷的作用與代謝,揭示PQQ作為GDH的輔酶共同參與對(duì)HX2菌株溶解無機(jī)磷作用影響機(jī)理。
1材料與方法
1.1.1 菌 株
RahnellaaquatilisHX2,Tn5插入突變pqq基因的突變體MH15,MH15的互補(bǔ)菌株CMH15(pqq),列出具體特性。表1
表 1 菌株及質(zhì)粒特征
Table 1 Characteristis of bacteria strains and plasmids
名稱Names特征Characteristics文獻(xiàn)來源Literatureresources水生拉恩氏菌RahnellaaquatilisHX2Apr,WildtypeChen[2]MH15Apr,Kmr,HX2derivativecontainingaTn5insertioninpqqEgeneGuo[3]CMH15(pqq)Apr,Kmr,Tcr,MH15containingplasmidpCH15withthepqqgenesGuo[3]質(zhì)粒PlasmidsCP465Tcr,pLAFR-5containingpqqgenes,cosmidGuo[3]pCH15Gmr,Tcr,pRK415Gcontainingapproximately8.0kbBamHIfragmentincludingpqqgenesfromcosmidCP465Guo[3]
注:Apr, Kmr, Gmrand Tcr分別表明抗氨芐青霉素、卡那霉素、慶大霉素和四環(huán)素
Note: Apr, Kmr, Gmrand Tcrindicate resistance to ampicillin, kanamycin, gentamicin and tetracycline, respectively
1.1.2 培養(yǎng)基
采用國(guó)際植物研究所磷酸鹽生長(zhǎng)培養(yǎng)基(NBRIP)、不同碳源NBRIP培養(yǎng)基和LB液體培養(yǎng)基參照焦子偉等[1]配方。
1.2.1碳源選擇
根據(jù)前期已有研究結(jié)果[1],選用蔗糖、乳糖、D-甘露糖、D-甘露醇、D-山梨醇、木糖、D-果糖和葡萄糖(作為對(duì)照)8種碳源進(jìn)行溶解無機(jī)磷的定性、定量分析。
1.2.2 溶磷定性檢測(cè)
將HX2、MH15、CMH15(pqq)菌株活化、搖培后,將菌懸液接種于含有直徑為0.5 cm的濾紙片的不同碳源NBRIP固體培養(yǎng)基平板上,并將各處理樣品進(jìn)行培養(yǎng),具體操作與檢測(cè)分析參照焦子偉等[1]溶磷平板定性檢測(cè)方法。
1.2.3 有效磷定量、pH檢測(cè)
將HX2、MH15、CMH15(pqq)菌株活化、搖培后,將菌懸液接種到不同碳源NBRIP液體培養(yǎng)基中進(jìn)行培養(yǎng),將所有處理樣品于不同搖培時(shí)間分別抽取搖培液進(jìn)行離心取上清液,進(jìn)行有效磷定量和pH的檢測(cè),具體操作與檢測(cè)參照焦子偉等[1]有效磷定量和pH值檢測(cè)方法。
采用EXCEL軟件進(jìn)行數(shù)據(jù)分析處理和SPSS軟件方差分析(ANOVA)。
2結(jié)果與分析
在8種不同碳源作為NBRIP固體培養(yǎng)基的碳源,經(jīng)7 d培養(yǎng),HX2、MH15、CMH15(pqq)菌株都有溶磷現(xiàn)象,溶磷圈直徑也各不相同。同一碳源溶磷培養(yǎng)基培養(yǎng)情況下,各菌株在D-果糖、D-山犁醇作為碳源情況下,其溶磷圈直徑無顯著差異;而在其它不同6種(木糖、蔗糖、乳糖、D-甘露糖、D-甘露醇和對(duì)照)碳源培養(yǎng)基情況下,其溶磷圈直徑差異顯著(P<0.05)。以D-山犁醇為例,其溶磷圈直徑最小,HX2 、MH15、CMH15(pqq)菌株溶磷直徑在1.35~1.43 cm;木糖、D-甘露糖和對(duì)照作為碳源,其溶磷圈直徑較大,如在D-甘露糖作為碳源情況下,HX2、CMH15(pqq)溶磷圈直徑分別為2.21、2.15 cm;突變體MH15溶磷圈直徑1.10 cm,缺失pqq基因的菌株溶磷圈直徑明顯減小。圖1,表2
注:不同碳源分別為A,木糖; B, D-甘露糖; C, D-甘露醇; D, D-山犁醇; E, 乳糖; F, 蔗糖; G, D-果糖;H,對(duì)照(葡萄糖);a, HX2; b, MH15; c, CMH15(pqq) ;下同
Note: Different carbon resources: A, Xylose; B, D-Mannose; C, D-Mannitol; D, D-Sorbitol; E, lactose; F, Surcose; G, D-fructose; H, control (glucose). a, HX2; b, MH15; c, CMH15(pqq);the same as bolow
圖1 不同處理和培養(yǎng)基下菌株溶磷圈
Fig.1 Clear halo of solubilization of tricalcium phosphate by strains under different treatment and medium
表2不同處理和培養(yǎng)基下菌株溶磷圈直徑 (cm)
Table 2 Phosphate-solubilizing halo diameter (cm) produced by strains under different treatment and medium
菌株Strains蔗糖Surcose乳糖LactoseD-果糖D-fructoseD-甘露醇D-MannitolD-山梨醇D-SorbitolD-甘露糖D-Mannose木糖Xylose對(duì)照ControlHX21.55±0.02a1.64±0.02a1.54±0.03a1.52±0.04a1.42±0.03a2.21±0.03a2.10±0.03a2.29±0.02aMH151.35±0.03b1.42±0.02b1.50±0.06a1.35±0.03b1.35±0.03a1.10±0.06b1.40±0.03b1.18±0.02bCMH15(pqq)1.50±0.06a1.57±0.03a1.55±0.03a1.53±0.03a1.43±0.02a2.15±0.09a2.08±0.04a2.36±0.03a
數(shù)據(jù)為平均值和標(biāo)準(zhǔn)誤差。(a-b),不同字母表示為顯著性差異(P<0.05)
Data was shown by Mean (± standard error) values. (a-b), different letters indicated statistically significant (P< 0.05)
8種碳源分別作為不同碳源NBRIP培養(yǎng)基,經(jīng)7 d培養(yǎng),HX2、MH15、CMH15(pqq)菌株在不同碳源NBRIP溶磷培養(yǎng)基上均能生長(zhǎng),但隨著培養(yǎng)時(shí)間延長(zhǎng),pH均逐漸下降,但pH各不相同,最終相對(duì)趨于穩(wěn)定。除D-果糖、D-山犁醇作為碳源溶磷培養(yǎng)基外,HX2、CMH15(pqq)與突變體MH15處理的pH值都有顯著性差異(P<0.05);以D-甘露糖、對(duì)照(葡萄糖)和木糖作為碳源培養(yǎng)基,HX2及其衍生菌株pH值變化較大。如木糖作為碳源的NBRIP培養(yǎng)基,HX2、CMH15(pqq)的pH分別為3.28、3.26,MH15突變體的pH 4.53,明顯增高。表3,圖2
表3 不同處理和培養(yǎng)基下菌株pH值
Table 3 pH observed by strains under different treatment and medium
菌株Strains蔗糖Surcose乳糖LactoseD-果糖D-fructoseD-甘露醇D-MannitolD-山梨醇D-SorbitolD-甘露糖D-Mannose木糖Xylose對(duì)照ControlHX24.17±0.03b4.62±0.04b4.21±0.08a4.19±0.06b4.75±0.02a3.72±0.03b3.28±0.05b3.44±0.02bMH154.34±0.02a4.89±0.06a4.36±0.03a4.34±0.02a4.72±0.06a4.19±0.03a4.53±0.06a4.89±0.02aCMH15(pqq)4.14±0.07b4.63±0.05b4.22±0.09a4.18±0.03b4.80±0.08a3.64±0.12b3.26±0.30b3.56±0.03b
注:虛線部分代表有效磷濃度變化圖;實(shí)線部分代表pH值變化
Note:pH of NBRIP after incubation was signed with the real line. Concentration of soluble-P was indicated by broken line
圖2不同處理和培養(yǎng)基下菌株pH和產(chǎn)有效磷變化曲線
Fig. 2Change curve of pH and concentration of soluble-P produced by strains under different treatment and medium
HX2、MH15、CMH15(pqq)菌株在8種不同碳源溶磷培養(yǎng)基上,經(jīng)7 d培養(yǎng),隨著培養(yǎng)時(shí)間延長(zhǎng),有效磷濃度逐漸上升,最終趨于相對(duì)穩(wěn)定;各菌株均都能產(chǎn)生有效磷,但產(chǎn)生有效磷的濃度各不相同。同一碳源NBRIP培養(yǎng)情況下,D-果糖和D-山犁醇作為碳源下,各菌株之間產(chǎn)生有效磷濃度差異不顯著;其余的如蔗糖、乳糖、D-甘露醇、D-甘露糖、木糖和對(duì)照作為碳源NBRIP培養(yǎng)基,野生菌株HX2、CMH15(pqq)與插入突變pqq基因的菌株MH15之間產(chǎn)生的有效磷濃度差異顯著(P<0.05)。各菌株在D-山犁醇作為碳源溶磷培養(yǎng)基中,產(chǎn)生的有效磷濃度最?。辉谀咎侵挟a(chǎn)生的最大,其次是葡萄糖和D-果糖。以木糖為例,HX2、CMH15(pqq)菌株產(chǎn)生的有效磷濃度分別為541.26和547.32 mg/L;MH15突變體產(chǎn)生的有效磷濃度為154.29 mg/L,產(chǎn)生的有效磷濃度最低。表4,圖2
表4不同處理和培養(yǎng)基下菌株產(chǎn)有效磷量
Table 4 Concentration of soluble-P produced by strains under different treatment and medium(mg/L)
菌株Strains蔗糖Surcose乳糖LactoseD-果糖D-fructoseD-甘露醇D-MannitolD-山梨醇D-SorbitolD-甘露糖D-Mannose木糖Xylose對(duì)照ControlHX2332.76±28.35b109.12±12.19a316.23±9.61a247.81±16.25a75.39±10.04a429.18±26.76a541.26±30.18a431.44±15.27aMH15249.02±14.61c86.90±6.49b306.90±7.81a212.92±12.36b81.24±16.22a252.49±13.37b154.29±4.32b91.19±2.98bCMH15(pqq)391.61±41.40a111.30±2.35a319.32±8.02a246.03±14.14a77.86±4.42a448.77±25.64a547.32±88.73a427.20±11.72a
3討 論
許多研究表明一些革蘭氏陰性菌如Pseudomonascepacia[4]、Rahnellaaquatilis[5]和Enterobacterintermedium60-2G[6]的PQQ 合成酶的pqq基因決定其溶解無機(jī)磷的能力[7]。野生菌株HX2在以葡萄糖、D-甘露醇、乳糖、D-甘露糖等為碳源的培養(yǎng)基中均可正常生長(zhǎng)[2]。研究以野生菌株HX2為供試研究對(duì)象,除葡萄糖作為NBRIP的碳源之外,把乳糖、蔗糖、木糖、D-甘露醇、D-甘露糖、D-山梨醇、D-果糖來作為NBRIP不同的7種碳源,進(jìn)行其溶磷定性、定量分析,HX2、CMH15(pqq)與MH15菌株之間在蔗糖、乳糖、D-甘露糖、D-甘露醇、木糖和葡萄糖6種碳源NBRIP培養(yǎng)基上產(chǎn)生的有效磷濃度差異顯著,這說明插入突變pqq的突變體很難利用不同碳源溶解難溶性的無機(jī)磷,也得出了類似的結(jié)果。
PQQ作為GDH等脫氫酶的輔酶,對(duì)GDH的功能發(fā)揮起關(guān)鍵控制作用,溶磷細(xì)菌通過GDH-PQQ 全酶作用能溶解土壤無機(jī)或有機(jī)磷酸鹽,促進(jìn)植物對(duì)營(yíng)養(yǎng)的攝入和植物生長(zhǎng)[4,6,8,9]。Rodríguez等[10]研究報(bào)道導(dǎo)入pqq基因的BurkholderiacepaciaIS-16 和假單孢菌屬(Pseudomonassp)兩個(gè)菌株能增強(qiáng)礦質(zhì)磷酸鹽溶解表型,促進(jìn)對(duì)磷的溶解。野生菌株HX2既能合成GDH和PQQ,在HX2菌株中,GDH都參與木糖、萄萄糖、D-甘露醇、D-甘露糖、乳糖、蔗糖、D-山梨醇、D-果糖溶磷代謝[1];PQQ參與木糖、葡萄糖、D-甘露醇、D-甘露糖、蔗糖、乳糖溶磷代謝,不參與D-山梨醇、D-果糖溶磷代謝;這說明PQQ作為GDH的輔酶參與了HX2菌株的木糖、葡萄糖、D-甘露糖、D-甘露醇、蔗糖、乳糖的溶磷代謝。這也可能說明了GDH有更好的底物特性,PQQ作為GDH重要的輔酶,但不是唯一的,PQQ的結(jié)構(gòu)類似物也可作為GDH氧化還原酶的輔酶或輔助因子參與溶磷代謝[11]。
MH16、MH15突變體在不同碳源溶磷培養(yǎng)基條件下也能產(chǎn)生有效磷,說明除葡萄糖溶磷主要機(jī)制外,可能還有其它的溶磷機(jī)制也參與HX2菌株的溶磷代謝。關(guān)于PQQ作為GDH的輔酶參與其溶磷產(chǎn)酸的調(diào)控機(jī)理,以及該菌株涉及的其它相關(guān)溶磷機(jī)理還有待進(jìn)一步深入研究。
4結(jié) 論
從PQQ參與不同碳源條件下對(duì)HX2菌株溶解無機(jī)磷作用影響結(jié)果分析,HX2菌株在8種不同碳源上具有不同的溶磷效果,PQQ除D-山梨醇、D-果糖外均參與該菌株對(duì)木糖、葡萄糖、D-甘露糖、D-甘露醇、蔗糖和乳糖溶磷代謝,以乳糖利用最低,木糖利用最高。PQQ作為GDH的輔酶,共同參與HX2菌株的木糖、葡萄糖、D-甘露糖、D-甘露醇、蔗糖和乳糖溶磷代謝,并起到重要調(diào)控作用。
參考文獻(xiàn)(References)
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Fund project:Supported by University Scientific Research Projects of Xinjiang Uygur Autonomous Region (XJEDU2014I041) and NSFC (31200386)
Influences of Pyrroloquinoline Quinone on Inorganic Phosphate
Solubilization under Different Carbon Sources in
RahnellaaquatilisHX2
JIAO Zi - wei1, ZHANG Xiang - feng1, ZHANG Na1, Wueren1, GUO Yan- bin2
(1.CollegeofChemistryandBiologicalSciences,YiliNormalUniversity,YiningXinjiang835000,China; 2.DepartmentofEcologyandEcologicalEngineering,CollegeofResourcesandEnvironmentalSciences,ChinaAgriculturalUniversity,Beijing100193,China)
Abstract:【Objective】 Rahnella aquatilis strain HX2 can produce glucose dehydrogenase (GDH) and pyrroloquinoline quinone (PQQ). PQQ as coenzyme of GDH jointly take part in metabolism of phosphate solubilization under glucose source in HX2 strain. Based on prior researches, this paper further revealed effects of PQQ on inorganic phosphate solubilization under different carbon source conditions in HX2 strain. 【Method】 HX2 wild strains, mutant MH15 and its complementary strains were used as test material. The methods of solubilzing phospate on plate, molybdenum-blue method and so on were used to analyze the qualitative and quantitative ability of phosphate solubilization under different carbon sources. 【Result】Except D-sorbitol and D-fructose, PQQ played a key role in HX2 phosphate solubilization with glucose, xylose, D-mannose, D-mannitol, sucrose and lactose as a sole carbon sources. However, its ability of phosphate solubilization was different with different carbon sources, which was the lowest for lactose and the highest for xylose as carbon sources. 【Conclusion】 It has been clear that PQQ and GDH as holoenzyme were involved in metabolism of phospate solubilization under different carbon sources such as glucose, xylose, D-mannose, D-mannitol, sucrose and lactose, and played an important regulatory role in HX2 strain.
Key words:PQQ; Rahnella aquatilis HX2; Carbon sources; Inorganic phosphate
通訊作者:郭巖彬(1978-),男,博士,副教授,研究方向?yàn)橹采锷鷳B(tài)學(xué)、土壤微生物、有機(jī)農(nóng)業(yè),(E-mail)guoyb@cau.edu.cn
作者簡(jiǎn)介:焦子偉(1973-),男,博士,副教授,研究方向?yàn)槲⑸锷鷳B(tài)及綠色有機(jī)農(nóng)業(yè)有害生物綜合防控,(E-mail)741285332@qq.com
基金項(xiàng)目:自治區(qū)高校科研計(jì)劃項(xiàng)目(XJEDU2014I041);國(guó)家自然科學(xué)基金項(xiàng)目(31200386)
收稿日期:2015-09-09
中圖分類號(hào):S188+.4
文獻(xiàn)標(biāo)識(shí)碼:A
文章編號(hào):1001-4330(2016)02-0295-07
doi:10.6048/j.issn.1001-4330.2016.02.015