| 水稻不同生长时期不同组织中抗砷内生菌的筛选与鉴定 |
| 摘要点击 1633 全文点击 625 投稿时间：2017-09-20 修订日期：2017-11-20 |
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| 中文关键词 水稻 砷 内生菌 16S rDNA 抗砷性 |
| 英文关键词 rice arsenic endophytic bacteria 16S rDNA arsenic resistance |
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| 中文摘要 |
| 微生物对于土壤-植物系统中砷的迁移转化有重要作用，植物内生菌是一种极其丰富的微生物资源，但至今尚未有研究报道植物内生菌对砷污染的响应.采用组织分离法和涂布平板法，以水稻（甬优-538）为研究对象，分别于水稻幼苗期、分蘖期、开花期和成熟期（2015年5~8月）分离根部、茎部、叶部、穗部（仅成熟期）可培养内生细菌，并通过16S rDNA序列进行菌种鉴定.对分离所得内生菌先用1 mmol·L-1亚砷酸钠[As（Ⅲ）]和10 mmol·L-1砷酸钠[As（Ⅴ）]进行抗砷筛选，再用2 mmol·L-1的As（Ⅲ）和20 mmol·L-1的As（Ⅴ）对初筛抗砷菌株进行复筛，以鉴定内生菌对不同砷形态的抗性.结果表明：共获得126株水稻内生菌，归为13个属，水稻幼苗期分离出8个属共37株菌；分蘖期分离出5个属共25株菌；开花期分离出8个属共24株菌；成熟期分离出8个属共30株菌.主要优势菌属为芽孢杆菌属（Bacillus sp.）、假单胞菌属（Psoudomonas sp.）和不动杆菌属（Acinetobacter sp.）.抗砷初筛选实验中得到20株菌对1 mmol·L-1的As（Ⅲ）和10 mmol·L-1的As（Ⅴ）的抗性较强，复筛发现其中16株菌对2 mmol·L-1 As（Ⅲ）有较强抗性，13株菌对20 mmol·L-1 As（Ⅴ）有较强抗性，其中菌株CS1对两种形态砷的耐性最显著. |
| 英文摘要 |
| Soil microorganisms are critical for arsenic transport and transformation in the soil-plant system. Endophytes are a very rich microbial resource, but to date no study has reported the responses of endophytes to arsenic pollution. In this study, the cultivable endophytic bacteria were isolated from the root, stem, leaf, and panicle of rice (Oryza sativa L. cv. Yongyou-538) at the seedling stage, tillering stage, flowering stage, and productive stage. All isolates were first screened by 1 mmol ·L-1 arsenite[As (Ⅲ)] and 10 mmol ·L-1 arsenate[As (Ⅴ)], and further screened by 2 mmol ·L-1 As (Ⅲ) and 20 mmol ·L-1 As (Ⅴ). From this study, a total of 126 strains of rice endophytes were obtained, belonging to 13 genera. Among them, 37 strains (8 genus) were isolated from the rice seedling stage, 25 strains (5 genus) were isolated from the rice tillering stage, 24 strains (8 genus) from the rice flowering stage, and 30 strains (8 genus) from the rice productive stage. The dominant genera were Bacillus sp., Psoudomonas sp., and Acinetobacter sp. After twice screening, 20 strains were found to be resistant to 1 mmol ·L-1 As (Ⅲ) and 10 mmol ·L-1 As (Ⅴ), including 16 strains that were resistant to 2 mmol ·L-1 As (Ⅲ) and 13 strains were resistant to 20 mmol ·L-1 As (Ⅴ). Importantly, the strain CS1 was found to be the most resistant bacteria to both As (Ⅲ) and As (Ⅴ) among all the isolated strains. |
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