NITRATE NON-UTILIZING MUTANTS OF FUSARIUM-OXYSPORUM AND THEIR USE IN VEGETATIVE COMPATIBILITY TESTS
NITRATE NON-UTILIZING MUTANTS OF FUSARIUM-OXYSPORUM AND THEIR USE IN VEGETATIVE COMPATIBILITY TESTS
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DOI：
10.1094/phyto-77-1640
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发表时间：
1987-12-01
期刊：
影响因子：
3.2
通讯作者：
LESLIE, JF
中科院分区：
文献类型：
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作者：
CORRELL, JC;KLITTICH, CJR;LESLIE, JF
7株尖孢镰刀菌分别在马铃薯-葡萄糖琼脂和添加1.5%氯酸钾的微量琼脂培养基上培养，获得了1300多个硝酸盐不利用（nit）突变体。突变体在微量琼脂培养基上的生长情况可分为3个表型类。这些类别可能反映了硝酸盐还原酶结构位点（nit1）、硝酸盐同化途径特异性调控位点（nit3）和影响硝酸盐还原酶活性（NitM）所需的含钼辅助因子组装的位点（至少五个）的突变。从所测的7株尖孢镰刀菌中分别获得了每个表型类的突变体。大多数（59-96%）的nit突变体为nit1突变体。在所有菌株中，用氯酸盐修饰的最小琼脂培养基中恢复nit3和NitM突变体的频率远高于用氯酸盐修饰的马铃薯葡萄糖琼脂培养基。对于7个菌株中的6个，来自同一亲本菌株的不同突变表型之间发生了生理互补（由于异核体的形成）。在具有相同表型的一些单元突变体之间也观察到互补。从一株西瓜芽孢杆菌中恢复的任何单位突变体之间均未观察到互补；这种菌株被命名为“异核体自不相容”。在之前的三个研究中，我们还确定了其他工人恢复的互补单元突变体（任意指定为nitA和nitB）的表型。nitA和nitB突变体都不对应于特定的突变表型；这三种表型均在nitA和nitB突变体中发现。除了异核体自不相容菌株外，来自单个菌株的所有nit1和nit3突变体都很容易与来自同一菌株的NitM突变体互补。NitM突变体形成异核体迅速、可靠，可作为鉴定尖孢镰刀菌属营养亲和性类群的一种突变体检测手段。有几种方法可以加快尖孢镰刀菌天然种群的营养相容性筛选。
Over 1,300 nitrate nonutilizing (nit) mutants were recovered from seven strains of Fusarium oxysporum cultured on two media, potato-dextrose agar or minimal agar, amended with 1.5% potassium chlorate. The mutants could be divided into three phenotypic classes by their growth on supplemented minimal agar medium. These classes presumably reflect mutations at a nitrate reductase structural locus (nit1), a nitrate-assimilation pathway-specific regulatory locus (nit3), and loci (at least five) that affect the assembly of a molybdenum-containing cofactor necessary for nitrate reductase activity (NitM). Nit mutants in each phenotypic class were recovered from each of the seven strains of F. oxysporum tested. The majority (59-96%) of nit mutants recovered were nit1 mutants. With all seven strains, nit3 and NitM mutants were recovered at a much higher frequency from minimal agar medium amended with chlorate than from potato-dextrose agar amended with chlorate. For six of the seven strains, physiological complementation occurred (as a result of heterokaryon formation) between the different nit mutant phenotypes derived from the same parental strain. Complementation also was observed between some nit mutants with the same phenotype. No complementation was observed between any of the nit mutants recovered from a strain of F. o. f. sp. melonis; this strain has been designated "heterokaryon self-incompatible". The phenotypes of complementary nit mutants (arbitrarily deisgnated nitA and nitB) recovered by other workers in three previous studies also were determined. Neither the nitA nor the nitB mutants corresponded to a particular mutant phenotype; all three phenotypes were found among the nitA and nitB mutants. With the exception of the heterokaryon self-incompatible strain, all nit1 and nit3 mutants from an individual strain readily complemented the NitM mutants derived from the same strain. The NitM mutants form heterokaryons rapidly and reliably and should be used as one of the nit mutant testers to identify the vegetative compatibility group to which isolates of F. oxysporum belong. Several procedures should expedite the screening of natural populations of F. oxysporum for vegetative compatibility.