Appl Environ Microbiol. 1997 Sep;63(9):3657-61. doi: 10.1128/aem.63.9.3657-3661.1997.
The accumulation of (beta)-carotene by the zygomycete Phycomyces blakesleeanus is increased by mutations in the carS gene. The treatment of spores of carS mutants with N-methyl-N(prm1)-nitro-N-nitrosoguanidine led to the isolation, at very low frequencies, of mutants that produced higher levels of (beta)-carotene. Strain S556 produced about 9 mg of (beta)-carotene per g of dry mass when it was grown on minimal agar. Crosses involving strain S556 separated the original carS mutation from a new, unlinked mutation, carF. The carF segregants produced approximately as much carotene as did carS mutants, but they were unique in their ability to produce zygospores on mating and in their response to agents that increase carotenogenesis in the wild type. The carotene contents of carF segregants and carF carS double mutants were increased by sexual interaction and by dimethyl phthalate but were not increased by light or retinol. Mixed opposite-sex cultures of carF carS mutants contained up to 33 mg of (beta)-carotene per g of dry mass. Another strain, S444, produced more (beta)-carotene than did S556 but was marred by slow growth, defective morphology, and bizarre genetic behavior. In all the strains tested, the carotene concentration was minimal during the early growth phase and became higher and constant for several days in older mycelia.
脉孢菌（Phycomyces blakesleeanus）中β-胡萝卜素的积累可以通过 carS 基因突变来增加。用 N-甲基-N(prm1)-亚硝基-N-亚硝基胍处理 carS 突变体的孢子，导致以非常低的频率分离出产生更高水平β-胡萝卜素的突变体。当在最小琼脂上生长时，菌株 S556 产生约 9mg/g 干重的β-胡萝卜素。涉及菌株 S556 的杂交将原始 carS 突变与新的、不连锁的突变 carF 分离。carF 分离株产生的类胡萝卜素与 carS 突变体大致相同，但它们具有独特的能力，即在交配时产生接合孢子，并对野生型中增加类胡萝卜素生物合成的试剂做出反应。carF 分离株和 carF carS 双突变体的类胡萝卜素含量通过性相互作用和邻苯二甲酸二甲酯增加，但不受光或视黄醇增加的影响。carF carS 突变体的混合异性培养物中含有高达 33mg/g 干重的β-胡萝卜素。另一个菌株 S444 产生的β-胡萝卜素比 S556 多，但生长缓慢，形态缺陷，遗传行为奇特。在所有测试的菌株中，类胡萝卜素浓度在早期生长阶段最低，在较老的菌丝体中几天内升高并保持恒定。
