| 摘要: |
| 海草植株共附生大量具有合成植物激素、促进植物营养物质吸收和拮抗病原菌作用的促生菌，对海草的健康生长具有重要作用。本研究利用固氮、溶磷培养基从海南省新村湾泰来草（Thalassia hemperichii）和海菖蒲(Enhalus acoroides)植株中获得细菌131株，分布于36属61种，其中芽孢杆菌属（Bacillus）为优势属。通过可培养细菌的多样性分析发现，从泰来草分离获得细菌的OTU（Operational Taxonomic Unit）数目、Chao和Shannon指数均高于海菖蒲，其具有更高的细菌多样性；而三种培养基中，应用PSM培养基获得的细菌的多样性最低。另外，对包括17株溶磷菌和12株固氮菌在内的61株菌进行促生特性分析，结果显示菌株L-2以 C2H4计的固氮酶活性达14.27 nmol/(h·mL) ，有3株菌溶磷活性在29.91～44.86 mg/L之间，6株菌产铁载体能力很强，8株菌氨化能力很强，10株菌吲哚乙酸（IAA）产量在50 μg/mL以上。基于促生能力的综合分析，我们筛选出5株具有较强促生潜能的菌株，16S rRNA鉴定结果显示其中2株为芽孢杆菌（Bacillus sp.），1株克雷伯氏菌（Klebsiella sp.），1株拉乌尔菌（Raoultella sp.）和1株Breoghania sp.。它们适合进一步开发研制为微生物菌剂，可应用于促进移植海草生长发育和退化海草床生态保护修复中。 |
| 关键词: 海洋生物学 泰来草 促生菌 固氮 溶磷 芽孢杆菌 |
| DOI：10.3969/J.ISSN.2095-4972.2021.02.003 |
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| 基金项目:国家重点研发计划资助项目(2017YFC0506301，2018YFC1406500)；国家自然科学基金资助项目(41976147，41676163)；中国科学院战略性先导科技专项资助项目A (XDA13020300)；中国科学院南海生态环境工程创新研究院创新发展基金资助项目（ISEE2018ZD02）；广东省海洋牧场规划、建设与管理工程技术研究资助项目 (GML2019ZD0402)；广东省公益研究与能力建设专项资金资助项目(2015A020216016)；广东省科技计划资助项目(2017B030314052)；广州市珠江科技新星资助项目（201806010017） |
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| Isolation and diversity of plant growth promoting bacteria on seagrass in Xincun Bay, Hainan |
| LIN Xian-cheng,DONG Jun-de,ZHOU Wei-guo,PENG Qiu-ying,ZHANG Jian,ZHANG Ying,YANG Qing-song,TANG Xiao-yu,ZHANG Yan-ying,LING Juan |
| (Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, CAS, Guangzhou 510301, China;Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 510301, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, CAS, Guangzhou 510301, China; University of Chinese Academy of Sciences, Beijing 100049, China;Key Laboratory of Tropical Marine Bioresources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, CAS, Guangzhou 510301, China;Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 510301, China;Tropical Marine Biological Research Station in Hainan, CAS, Sanya 572000, China; Innovation Academy of South China Sea Ecology and Environmental Engineering, CAS, Guangzhou 510301, China) |
| Abstract: |
| Many seagrassassociated and growthpromoting bacteria are able to synthetize phytohormone, facilitate nutrient absorption and help to resist pathogens and they play a vital role in seagrass growth and primary production. In this study, 131 strains in 36 genus and 61 species, dominated mostly by genus Bacillus were isolated from seagrass Thalassia hemperichii and Enhalus acoroide in Xincun Bay, Hainan, using phosphorus or nitrogen limited medium. The diversity analysis indicated that sample from T. hemperichii had higher OTU numbers, Chao and Shannon index thanE. acoroide, suggesting a higher bacterial diversity in contrast to the results from PSM medium which got the lowest diversity among the three media. Moreover, 61 strains including 17 phosphate-solubilizing bacteria and 12 nitrogenfixing bacteria were randomly selected to test the plant growthpromoting traits. The results showed that the nitrogenase activity of strain L-2 reached 14.27 nmol C2H4·h-1·mL-1, and the dissolving phosphorus content of 3 strains ranged from 29.91 to 44.86 mg/L. Meanwhile, 6 strains had good performance in producing siderophore, 8 strains of selected strains were superior to produce NH3 and 10 strains’ IAA yields were higher than 50 μg/mL. Based on the analyses, 5 strains are considered as potential seagrass growthpromoting bacteria. The 16S rRNA gene sequencing results showed that 2 strains were Bacillus sp., and the remains were Klebsiellasp., Raoultella sp. and Breoghaniasp., respectively. Thus, these 5 bacteria can be developed as microbial inoculant in the future work and applied to stimulate the growth of transplanted seagrass for the protection and restoration of seagrass ecosystem. |
| Key words: marine biology Thalassia hemperichii plant growth promoting bacterium nitrogen fixing phosphate solubilizing Bacillus |
