芘降解菌Pseudomonas sp. PR3的植物促生特性及其对芘胁迫下水稻生长的影响

doi:10.13560/j.cnki.biotech.bull.1985.2022-0539

摘要/Abstract

摘要：

农田中不断积累的多环芳烃不仅严重影响作物生长,同时增加粮食安全风险。筛选兼具促进植物生长特性和降解污染物功能的微生物菌株是解决上述问题的一种有效手段。从油田附近生长的植物根表分离得到一株具有芘降解能力,同时还具有溶磷、产吲哚乙酸和铁载体等植物促生特性的菌株PR3,经16S rDNA序列同源性分析确定为假单胞菌（Pseudomonas sp.）。菌株PR3在无机盐培养液中生长14 d后,对芘（20 mg/L）的降解率可达94%,对萘（50 mg/L）、菲（50 mg/L）、苯并（a）芘（10 mg/L）的降解率也分别达到92%,84%和47%。同时,该菌株7 d内最大溶磷量为756.25 mg/L,2 d内IAA合成量可达14.46 mg/L,4 d内生成铁载体的活性单位可达58.53%。在不同芘污染浓度处理下的盆栽实验表明,接种PR3可有效促进水稻生长并提高根际土壤中芘的降解,去除率可达72.02%-86.22%,同时显著降低水稻根及地上部中的芘含量,分别为21.81%-53.01%和49.81%-57.17%。因此,菌株PR3有助于实现芘污染土壤的生态修复以及降低作物芘暴露的风险。

关键词: 芘降解菌, 植物促生特性, 水稻, 土壤修复, 氧化应激

Abstract:

The accumulation of polycyclic aromatic hydrocarbons（PAHs）in farmland not only seriously hinder crop growth,but also increase food security risks. Screening the microorganisms with both the functions of promoting plant growth and degrading pollutants is an effective means to solving the above problems. Strain PR3 was isolated from the root surface of plants growing near the oil field,which had the ability of degrading pyrene,and also showed the properties of promoting plant growth like phosphorus dissolution,indole acetic acid and siderophore production. The results of 16S rDNA sequence analysis showed that the strain was classified as Pseudomonas sp. After growing in PMM medium containing 20 mg/L pyrene for 14 d,the degradation rate of pyrene by strain PR3 reached 94%. The degradation rates of naphthalene（50 mg/L）,phenanthrene（50 mg/L）and benzo（a）pyrene（10 mg/L）at 14 d were 92%,84% and 47%,respectively. Furthermore,the maximum dissolved phosphorus amount of strain PR3 was 756.25 mg/L in 7 d,the synthesis amount of IAA in 2 d was up to 14.46 mg/L,and the synthetic siderophore activity unit in 4 d reached 58.53%. Greenhouse pot experiments under different pyrene contamination concentration demonstrated that the inoculation of strain PR3 significantly improved the growth of rice and increased the degradation of pyrene near rhizosphere,and the removal rate reached 72.02%-86.22%. Meanwhile,the pyrene contents in the roots and shoots decreased by 21.81%-53.01% and 49.81%-57.17%,respectively. These results indicated that strain PR3 could contribute to the ecological remediation of pyrene-contaminated soil and reduce the risk of pyrene exposure to crops.

Key words: pyrene-degrading bacteria, plant growth-promoting properties, rice, soil remediation, oxidative stress

高晓蓉, 丁尧, 吕军. 芘降解菌Pseudomonas sp. PR3的植物促生特性及其对芘胁迫下水稻生长的影响[J]. 生物技术通报, 2022, 38(9): 226-236.

GAO Xiao-rong, DING Yao, LV Jun. Effects of Pseudomonas sp. PR3,a Pyrene-degrading Bacterium with Plant Growth-promoting Properties,on Rice Growth Under Pyrene Stress[J]. Biotechnology Bulletin, 2022, 38(9): 226-236.

图/表 8

表1 菌株的植物促生特性

Table 1 Plant growth-promoting traits of the isolated strains

菌株编号 Strain No.	溶磷量 Phosphate solubilisation/（mg·L^-1）	IAA生成量 IAA production/（mg·L^-1）	铁载体显色圈 Siderophore color circle/（D·d^-1）	铁载体活性单位 Siderophore activity unit/%
PR1	736.77±20.30	11.38±0.33	2.76±0.34	57.67±1.21
PR2	702.25±28.60	2.40±0.81	5.17±1.02	62.57±3.20
PR3	756.25±15.01	14.46±0.20	2.53±0.52	58.53±3.62
PR4	893.46±25.38	9.24±0.84	1.05±0.45	38.47±3.15
PR5	842.80±36.84	9.50±0.88	1.25±0.11	31.24±1.55
PR6	762.09±24.75	4.05±0.61	1.02±0.28	25.67±1.87

图1 菌株PR3的系统发育树

Fig. 1 Phylogenetic tree of strain PR3

图2 菌株PR3的芘降解能力 A：菌株PR3对20 mg/L芘的降解曲线及生长曲线;B：菌株PR3对不同浓度芘的降解曲线

Fig. 2 Degradation of pyrene by strain PR3 A：The degradation dynamics and the growth curve of strain PR3 of pyrene with an initial concentration of 20 mg/L. B：The degradation dynamics of pyrene at different concentration

表2 菌株PR3对其他PAHs的降解能力

Table 2 Degradability of strain PR3 for other PAHs types

PAHs	初始浓度 Initial concentration/ （mg·L^-1）	降解时间 Degrading time/d	PAHs降解率 Degradation rate of PAHs/%
萘 Nap	50	7	91.56±1.35
萘 Nap	50	14	92.45±1.04
菲Phe	50	7	52.39±5.78
菲Phe	50	14	84.70±1.54
苯并（a）芘 Bap	10	7	46.37±7.48
苯并（a）芘 Bap	10	14	47.16±2.66

图3 接种菌株PR3对水稻生长的影响 S0：未污染土壤;S1,S2,S3：芘初始浓度为9.58 mg/kg,43.80 mg/kg,90.67 mg/kg的污染土壤;CP：仅种植水稻;CPR：水稻根际接种PR3。下同

Fig. 3 Effects of inoculated strain PR3 on rice growth S0：Uncontaminated soil;S1,S2,S3：initial concentration of pyrene in the contaminated soil was 9.58 mg/kg,43.80 mg/kg and 90.67 mg/kg. CP：Only planted rice in the contaminated soil;CPR：planted rice inoculated with strain PR3 via root irrigation in the contaminated soil. The same below

表3 接种菌株PR3 30 d后水稻的生物量

Table 3 Biomass of rice at 30 d after inoculation with strain PR3

处理 Treatment		地上部 Shoot		根 Root
处理 Treatment		鲜重Fresh weight/（mg·pot^-1）	干重Dry weight/（mg·pot^-1）	鲜重Fresh weight/（mg·pot^-1）	干重Dry weight/（mg·pot^-1）
S0	CP	2861.76±16.80 c	774.40±15.12 b	1775.95±39.67 bc	303.60±17.08 c
	CPR	3536.13±103.75 ab	860.93±20.17 a	2456.30±162.76 a	368.13±18.42 a
S1	CP	3081.10±71.56 bc	792.00±20.61 b	1532.85±154.78 cd	287.47±18.87 cd
	CPR	3380.85±70.78 b	871.20±21.78 a	1894.20±60.74 b	334.40±7.21 b
S2	CP	2681.43±75.64 c	630.67±17.54 c	1611.13±154.24 c	262.90±14.55 d
	CPR	3788.40±82.44 a	854.70±31.33 a	2323.75±103.45 a	373.63±9.61 a
S3	CP	2069.10±105.98 d	493.53±12.12 d	1155.00±113.43 d	255.93±16.66 d
	CPR	3513.95±119.01 ab	838.57±30.83 ab	2113.10±49.78 a	346.13±14.77 ab

图4 菌株PR3对水稻光合作用及氧化应激的影响不同处理下的叶绿素含量（A）、SOD酶活性（B）、POD酶活性（C）以及MDA含量（D）。不同字母表示各处理间差异显著（P<0.05）,下同

Fig. 4 Effects of strain PR3 on photosynthesis and oxidative stress of rice Chlorophyll content（A）,SOD activity（B）,POD activity（C）and MDA content（D）under different treatments. The different lowercase letters indicate significant differences among treatments at P<0.05 levels,the same below

图5 接种菌株PR3对水稻（A）及土壤（B）中芘含量的影响 CK：污染土壤对照;CB：土壤中接种PR3

Fig. 5 Effects of strain PR3 on pyrene content in rice（A）and soil（B） CK：Contaminated soil as control;CB：contaminated soil inoculated with strain PR3

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