Małek W, Kowalski M
Acta Microbiol Pol. 1977;26(4):345-50.
Mutants isolated from effective R. meliloti strain L5-30 which required histidine (his-240), arginine+uracil (arg-55) and cysteine (cys-243, cys-244 and cys-246) showed also loss of effectiveness. Mutant requiring isoleucine+valine (ilv-74) was non-infective. Relation of the metabolic deficiency to the symbiotic properties of these mutants was tested comparing symbiotic response of their prototrophic revertants and transductants. It was found that all revertants and transductants of the strain his-240 were effective which suggests that histidine deficiency was the cause of their ineffectiveness. All revertants and transductants of the cysteine mutants were still ineffective. This result indicates two independent mutations which were not cotransductible. Prototrophic revertants of the mutant arg-55 were ineffective whereas 56.9 percent of transductants appeared effective suggesting close linkage of two mutations. i.e. auxotrophic and the other concerned with symbiotic effectiveness. Though one of 69 prototrophic transductants obtained from the non-nodulating mutant ilv-74 remained non-nodulating, it seems that changes in nodulating ability of the mutant are related to the auxotrophic requirements.
从有效的苜蓿根瘤菌菌株L5 - 30分离出的突变体，其中需要组氨酸（his - 240）、精氨酸+尿嘧啶（arg - 55）和半胱氨酸（cys - 243、cys - 244和cys - 246）的突变体也表现出有效性丧失。需要异亮氨酸+缬氨酸（ilv - 74）的突变体无感染性。通过比较这些突变体的原养型回复体和转导子的共生反应，测试了代谢缺陷与这些突变体共生特性的关系。发现his - 240菌株的所有回复体和转导子都是有效的，这表明组氨酸缺乏是其无效的原因。半胱氨酸突变体的所有回复体和转导子仍然无效。这一结果表明存在两个独立的、不可共转导的突变。arg - 55突变体的原养型回复体无效，而56.9%的转导子表现出有效，这表明两个突变紧密连锁，即一个是营养缺陷型，另一个与共生有效性有关。虽然从非结瘤突变体ilv - 74获得的69个原养型转导子中有一个仍然是非结瘤的，但似乎该突变体结瘤能力的变化与营养缺陷需求有关。
