Chavez-Ontiveros Jeanett, Martinez-Espinoza Alfredo D, Ruiz-Herrera Jose
1 Departamento de Ingeniería Genética, Unidad Irapuato, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 629, Irapuato, Gto. 36500, México.
New Phytol. 2000 May;146(2):335-341. doi: 10.1046/j.1469-8137.2000.00635.x.
Using genetic crosses between single chs mutants of Ustilago maydis inoculated into maize (Zea mays) seedlings, two classes of double mutants affected in genes coding for chitin synthetases were isolated: chs3/chs4, and chs4/chs5. Analysis of the mutants showed almost no change in their phenotype compared with wild-type strains. Growth rate, effect of stress conditions, dimorphic transition and mating were not affected. The only salient differences were increased sensitivity to osmotics at acid pH, and decrease in chitin synthetase activity, especially when measured with CO , and in chitin content. Most significant was a decrease in virulence, although this appeared to be due a factor unrelated to CHS genes. These data can be taken as further evidence that multigenic control of chitin synthetase in fungi operates as a safety mechanism to guarantee fungal viability in changing and hostile environmental conditions.
通过将玉米黑粉菌的单个chs突变体之间进行遗传杂交，并接种到玉米（Zea mays）幼苗中，分离出了两类在几丁质合成酶编码基因上受影响的双突变体：chs3/chs4和chs4/chs5。对这些突变体的分析表明，与野生型菌株相比，它们的表型几乎没有变化。生长速率、应激条件的影响、二态转变和交配均未受影响。唯一显著的差异是在酸性pH值下对渗透压的敏感性增加，几丁质合成酶活性降低，尤其是用CO测量时，以及几丁质含量降低。最显著的是毒力下降，尽管这似乎是由一个与CHS基因无关的因素导致的。这些数据可以作为进一步的证据，证明真菌中几丁质合成酶的多基因控制作为一种安全机制，以保证真菌在不断变化的恶劣环境条件下的生存能力。
