Laboratorio de Biología Molecular de Hongos y Plantas, División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica A.C., San Luis Potosí, Mexico.
Laboratorio de Biología Molecular de Bacterias y Levaduras, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, México City, Mexico.
Sci Rep. 2019 Jul 25;9(1):10813. doi: 10.1038/s41598-019-47133-4.
Ustilago maydis is a dimorphic fungus that has emerged as a model organism for the study of fungal phytopathogenicity and RNA biology. In a previous study, we isolated the U. maydis UmRrm75 gene. The deletion of the UmRrm75 gene affected morphogenesis and pathogenicity. UmRrm75 gene encodes a protein containing three RNA recognition motifs. Here we determined that UmRrm75 has chaperone activity in Escherichia coli using the transcription anti-termination assay. Subsequently, we analyzed the growth of ΔUmRrm75 mutants at 15 °C and 37 °C, observing that mutant strains had reduced growth in comparison to parental strains. UmRrm75 gene expression was induced under these non-optimal temperatures. ΔUmRrm75 mutant colonies displayed a dark-brown color at 28 °C, which was confirmed to be melanin based on spectroscopic analysis and spectrometric data. Furthermore, ΔUmRrm75 mutant strains showed the presence of peroxisomes, and increased HO levels, even at 28 °C. The ΔUmRrm75 mutant strains displayed a higher expression of redox-sensor UmYap1 gene and increased catalase activity than the parental strains. Our data show that deletion of the UmRrm75 gene results in higher levels of HO, increased melanin content, and abiotic stress sensitivity.
玉米黑粉菌是一种二型真菌，已成为研究真菌植物病原性和 RNA 生物学的模式生物。在之前的一项研究中，我们分离出了玉米黑粉菌 UmRrm75 基因。该基因的缺失影响形态发生和致病性。UmRrm75 基因编码一种含有三个 RNA 识别基序的蛋白质。在这里，我们使用转录抗终止测定法确定 UmRrm75 在大肠杆菌中具有伴侣活性。随后，我们分析了在 15°C 和 37°C 下ΔUmRrm75 突变体的生长情况，观察到与亲本菌株相比，突变菌株的生长减少。在这些非最佳温度下，UmRrm75 基因表达被诱导。在 28°C 时，ΔUmRrm75 突变体菌落呈现深褐色，这通过光谱分析和光谱数据证实是黑色素。此外，ΔUmRrm75 突变菌株表现出过氧化物酶体的存在，并且即使在 28°C 时 HO 水平也增加。ΔUmRrm75 突变株的氧化还原传感器 UmYap1 基因表达更高，过氧化氢酶活性也高于亲本菌株。我们的数据表明，UmRrm75 基因的缺失导致更高水平的 HO、增加的黑色素含量和非生物胁迫敏感性。
