RRNA operon copy number reflects ecological strategies of bacteria
RRNA operon copy number reflects ecological strategies of bacteria
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DOI：
10.1128/aem.66.4.1328-1333.2000
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发表时间：
2000-04-01
影响因子：
4.4
通讯作者：
Schmidt, TM
中科院分区：
文献类型：
--
作者：
Klappenbach, JA;Dunbar, JM;Schmidt, TM
虽然自然选择似乎有利于消除原核生物中的基因冗余，但在细菌染色体上，每个rRNA编码基因的多个副本是常见的。尽管与单拷贝基因有明显的偏离，但没有表型与rRNA基因拷贝数一致相关。我们发现rRNA基因的数量与系统发育不同的细菌对资源可用性的反应速度有关，在营养复杂的介质中迅速形成菌落的土壤细菌平均含有5.5个小亚单位rRNA基因，而反应缓慢的细菌平均含有1.4个拷贝。在除草剂2，4-二氯苯氧基乙酸(2，4-D)冲击的土壤微宇宙中，具有多个rRNA基因(X)的2，4-D降解菌在未改良对照中占优势，而rRNA基因(X)较少(bar=2.7)的降解菌在对照中占优势。这些发现证明了与rRNA基因拷贝数相关的表型效应，这表明生态策略影响着自然微生物群落的结构。
Although natural selection appears to favor the elimination of gene redundancy in prokaryotes, multiple copies of each rRNA-encoding gene are common on bacterial chromosomes. Despite this conspicuous deviation from single-copy genes, no phenotype has been consistently associated with rRNA gene copy number. We found that the number of rRNA genes correlates with the rate at which phylogenetically diverse bacteria respond to resource availability, Soil bacteria that formed colonies rapidly upon exposure to a nutritionally complex medium contained an average of 5.5 copies of the small subunit rRNA gene, whereas bacteria that responded slowly contained an average of 1.4 copies. In soil microcosms pulsed with the herbicide 2, 4-dichlorophenoxy-acetic acid (2,4-D), indigenous populations of 2,4-D-degrading bacteria with multiple rRNA genes ((x) over bar = 5.4) became dominant, whereas populations with fewer rRNA genes ((x) over bar = 2.7) were favored in unamended controls. These findings demonstrate phenotypic effects associated with rRNA gene copy number that are indicative of ecological strategies influencing the structure of natural microbial communities.