种子固有细菌是植物内生细菌的重要来源, 对植物的健康以及接种细菌的定殖能产生重要影响。该文以杂交水稻(Oryza sativa)种子为研究对象, 比较研究了不同品种水稻种子中固有细菌群落的多样性。利用799f和1492r这对引物成功地从水稻种子中扩增出固有细菌16S rDNA片段; 通过构建16S rDNA文库和扩增核糖体RNA基因酶切分型(ARDRA)的方法, 对杂交水稻 ‘丰优611’ (‘丰源A’ × ‘远恢611’)、‘金优611’ (‘金23A’ × ‘远恢611’)和‘金23A/09H013’ ( ‘金23A’ × ‘09H013’) 3个组合的子代及其各自亲本的种子固有细菌群落结构的多样性进行了研究。构建的7个克隆文库中, 每个文库含有200-300个克隆, 30-40个操作分类单元(OTU), 对ARDRA分型得到的代表序列进行分析, 在16S rDNA文库中发现多种细菌类群, 包括α变形杆菌(α-Proteobacteria)、β变形杆菌、γ变形杆菌、放线菌(Actinobacteria)、厚壁菌(Firmicutes)和拟菌(Bacteroidetes), 优势菌属是泛菌属(Pantoea)和芽孢杆菌属(Bacillus)。不同品种的水稻种子固有细菌群落结构不同, 而杂交子代种子中的优势菌与亲本种子中的优势菌在种类和数量上都具有一定的相关性。此外, 子代种子中丰度5%以上的细菌也能在各自父本或母本中检测到。

Aims Our purpose is to study the bacterial community structures in rice (Oryza sativa) seeds, and to compare and analyze community structures in different varieties in different hybrid combinations.
Methods Primers 799f and 1492r were used to amplify the bacterial 16S rDNA genes in the rice seeds. The community structure and diversity of indigenous bacteria in the rice seeds of hybrid progenies and their parental lines in three hybrid rice combinations, including ‘Fengyou 611’ (‘Fengyuan A’ × ‘Yuanhui 611’), ‘Jinyou 611’ (‘Jin 23A’ × ‘Yuanhui 611’) and ‘Jin 23A/09H013’ (‘Jin 23A’ × ‘09H013’), were analyzed by the 16S rDNA clone library technique and amplified by ribosomal DNA restriction analysis (ARDRA).
Important findings In seven clone libraries, each library had 200-300 positive clones and 30-40 operational taxonomic units (OTUs). Analysis for the representative sequences identified by ARDRA revealed diverse phyla of bacteria in the 16S rDNA libraries, which consisted of alpha, beta, and gamma subclasses of Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes. The dominant genera were Pantoea and Bacillus. Indigenous bacterial communities in the rice seeds of different varieties were different. The dominant bacteria in the hybrid progeny seeds had some relationship with that of their parental seeds in both variety and quantity. When the most abundant bacterial genera of both parental seeds were the same, such as Pantoea, the most abundant bacterial genus in the hybrid progeny seeds was also Pantoea, but with higher contents than that in the parents, as in the combination of ‘Fengyou 611’. When the most abundant bacterial genera in the two parental seeds were different and the abundance of the dominant bacterial genus in the male parent was < 50%, the dominant bacterial genus in the hybrid progeny seeds was the same as its female parental seeds, but with greater abundance, such as the combination ‘Jinyou 611’. However, when the abundance of the first dominant bacterial genus in the male parental seeds was > 50%, the most abundant bacterial genus in the hybrid progeny seeds was the same, and the abundance was lower than that in the male parental seeds, such as the combination ‘Jin 23A/09H013’.