Natural antisense transcripts are linked to the modulation of mitochondrial function and teliospore dormancy in Ustilago maydis

Abstract

The basidiomycete smut fungus Ustilago maydis causes common smut of corn. This disease is spread through the production of teliospores, which are thick-walled dormant structures characterized by low rates of respiration and metabolism. Teliospores are formed when the fungus grows within the plant, and the morphological steps involved in their formation have been described, but the molecular events leading to dormancy are not known. In U. maydis, natural antisense transcripts (NATs) can function to alter gene expression and many NATs have increased levels in the teliospore. One such NAT is as-ssm1 which is complementary to the gene for the mitochondrial seryl-tRNA synthetase (ssm1), an enzyme important to mitochondrial function. The disruption of ssm1 leads to cell lysis, indicating it is also essential for cellular viability. To assess the function of as-ssm1, it was ectopically expressed in haploid cells, where it is not normally present. This expression led to reductions in growth rate, virulence, mitochondrial membrane potential and oxygen consumption. It also resulted in the formation of as-ssm1/ssm1 double-stranded RNA and increased ssm1 transcript levels, but no change in Ssm1 protein levels was detected. Together, these findings suggest a role for as-ssm1 in facilitating teliospore dormancy through dsRNA formation and reduction of mitochondrial function.

Genome‐wide identification of long non‐coding RNAs suggests a potential association with effector gene transcription in Phytophthora sojae

“…lncRNAs can control the expression of nearby genes using cis ‐ and trans ‐acting regulation (Kim and Sung, ). Alteration of the expression level of lncRNAs can result in elevated transcription levels of nearby protein‐coding genes; deletion of lncRNAs can lead to decreased virulence of pathogens (Donaldson and Saville, ; Donaldson et al ., ; Morrison et al ., ; Ostrowski and Saville, ). lncRNAs have a wide range of functions in a variety of biological processes, including modulation of the localization and activity of proteins, serving as precursors for small RNAs or as structural RNAs, and affecting the processing of other RNAs (Wilusz et al ., ).…”

A novel antisense long non‐coding RNA participates in asexual and sexual reproduction by regulating the expression of GzmetE in Fusarium graminearum

“…In the plant pathogenic fungus U. maydis, the expression of NAT as-um02151 caused a twofold increase in um02151 mRNA levels but did not change the protein level of Um02151 (Donaldson and Saville, 2013). In subsequent research, the researchers found the NAT as-ssm1 was ectopically expressed in haploid cells and its expression led to reductions in growth rate and virulence of U. maydis (Ostrowski and Saville, 2017). These studies suggest that lncRNAs also play important regulatory roles in filamentous fungi.…”

“…In subsequent research, the researchers found the NAT as‐ssm1 was ectopically expressed in haploid cells and its expression led to reductions in growth rate and virulence of U . maydis (Ostrowski and Saville, 2017). These studies suggest that lncRNAs also play important regulatory roles in filamentous fungi.…”

Endophytic bacterium Pseudomonas protegens suppresses mycelial growth of Botryosphaeria dothidea and decreases its pathogenicity to postharvest fruits

“…Glycoside hydrolase (GHY) functioned as an important determinant of virulence in Coniella vitis ( Qin et al, 2020 ), Phytophthora sojae ( Ma et al, 2015 ), and Pyricularia oryzae ( Pan et al, 2021 ). Aminoacyl-tRNA synthetase (ATS) was a vital factor in the cellular viability of Ustilago maydis ( Ostrowski and Saville, 2017 ) and germination and blastospore yield in Beauveria bassiana ( Zhu et al, 2017 ). Alpha/beta hydrolase (α/β-HY) was involved in the Fusarium graminearum pathogenicity ( Jiao and Peng, 2018 ).…”