Genetic diversity among Frankia strains nodulating members of the family Casuarinaceae in Australia revealed by PCR and restriction fragment length polymorphism analysis with crushed root nodules
Genetic diversity among Frankia strains nodulating members of the family Casuarinaceae in Australia revealed by PCR and restriction fragment length polymorphism analysis with crushed root nodules
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DOI：
10.1128/aem.62.3.979-985.1996
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发表时间：
1996-03
影响因子：
4.4
通讯作者：
C. Rouvier;Y. Prin;P. Reddell;P. Normand;P. Simonet
中科院分区：
文献类型：
--
作者：
C. Rouvier;Y. Prin;P. Reddell;P. Normand;P. Simonet
直接从根瘤中提取的DNA被用来评估与自然生长在澳大利亚东北部的两个木麻黄属和两个木麻黄属共生的Frankia菌株的遗传多样性。从田间采集的木麻黄感染Frankia菌株的根瘤或参考培养物中提取的DNA作为模板，用针对核糖体操纵子和nif操纵子的两个DNA区域的引物进行PCRS。然后用一组限制性内切酶对扩增产物进行分析。在这些限制模式的基础上识别了五个不同的遗传群体。这些类群始终与结核起源的寄主物种有关。所有分离的参考菌株都有相似的模式，并与澳大利亚木麻黄的8个未分离的Frankia菌株中的6个一起被归入组1。组2包括木麻黄的两个未分离的Frankia菌株，而组3至5分别包括所有未分离的木麻黄、木麻黄、木麻黄和木麻黄。这些结果表明，与以往分离菌株的分子研究结果相反，感染木麻黄科成员的Frankia菌株之间存在遗传多样性。在以前的研究中，Frankia菌株的高度同源性可能与获得菌株的单一寄主物种有关，并且这些菌株来自木麻黄科成员的自然地理范围以外的地区，那里的遗传多样性可能低于澳大利亚。
DNA extracted directly from nodules was used to assess the genetic diversity of Frankia strains symbiotically associated with two species of the genus Casuarina and two of the genus Allocasuarina naturally occurring in northeastern Australia. DNA from field-collected nodules or extracted from reference cultures of Casuarina-infective Frankia strains was used as the template in PCRs with primers targeting two DNA regions, one in the ribosomal operon and the other in the nif operon. PCR products were then analyzed by using a set of restriction endonucleases. Five distinct genetic groups were recognized on the basis of these restriction patterns. These groups were consistently associated with the host species from which the nodules originated. All isolated reference strains had similar patterns and were assigned to group 1 along with six of the eight unisolated Frankia strains from Casuarina equisetifolia in Australia. Group 2 consisted of two unisolated Frankia strains from C. equisetifolia, whereas groups 3 to 5 comprised all unisolated strains from Casuarina cunninghamiana, Allocasuarina torulosa, and Allocasuarina littoralis, respectively. These results demonstrate that, contrary to the results of previous molecular studies of isolated strains, there is genetic diversity among Frankia strains that infect members of the family Casuarinacaeae. The apparent high homogeneity of Frankia strains in these previous studies probably relates to the single host species from which the strains were obtained and the origin of these strains from areas outside the natural geographic range of members of the family Casuarinaceae, where genetic diversity could be lower than in Australia.