How TrPLDs Influence Apple Disease Severity

Greg Howard
20th April, 2024

How TrPLDs Influence Apple Disease Severity

Image Source: Natural Science News, 2024

Key Findings

  • Study in Gansu Agricultural University found a fungus gene, TrPLD1, crucial for infecting apples
  • Deleting TrPLD1 reduced the fungus's growth and ability to damage apple cell walls
  • The TrPLD2 gene deletion did not affect the fungus, showing TrPLD1's unique role
Phospholipase D (PLD) is an enzyme that has been implicated in various critical cellular processes, including growth, morphogenesis, and host-pathogen interactions in different organisms. In the realm of plant pathology, understanding the role of PLD in the pathogenicity of filamentous fungi is of particular interest because these fungi can cause diseases in crops, leading to significant agricultural losses. The recent study conducted by researchers at Gansu Agricultural University sheds light on how PLD influences the pathogenicity of a specific filamentous fungus, Trichothecium roseum[1]. Trichothecium roseum is known for causing spoilage in apples, a common and economically important fruit crop. The study aimed to determine the role of two PLD genes, TrPLD1 and TrPLD2, in the fungus's ability to infect and cause disease in apples. To achieve this, the researchers utilized mutant strains of T. roseum where each of these genes had been individually deleted. The study found that deleting the TrPLD1 gene (creating the ΔTrPLD1 mutant) had a significant impact on the fungus's ability to germinate and grow. Specifically, the ΔTrPLD1 mutant showed delayed spore germination and reduced germ tube elongation. This was attributed to the downregulation of key genes (TrbrlA, TrabaA, and TrwetA) involved in the developmental processes of the fungus. Essentially, without functional TrPLD1, the fungus struggles to initiate the early stages of infection. Furthermore, the ΔTrPLD1 mutant demonstrated a reduced ability to break down the cell wall of apple fruits and alter the fruit's fatty acid content during infection. This was linked to lower expression levels of genes coding for enzymes that degrade the fruit's cell wall. As a result, the integrity of the apple's cell membrane was better preserved, and the levels of malondialdehyde (MDA), a marker of oxidative stress and cell damage, were lower in fruits infected with the ΔTrPLD1 mutant compared to those infected with the wild-type fungus. Consequently, the pathogenicity of the ΔTrPLD1 mutant was diminished, and the quality of the infected apples was maintained to a higher degree. On the other hand, the deletion of the TrPLD2 gene (ΔTrPLD2 mutant) did not show a significant effect on the infection process. This suggests that TrPLD1 and TrPLD2 have distinct roles in the life cycle and pathogenicity of T. roseum, with TrPLD1 being more critical in these processes. The findings of this study are in line with previous research on the role of PLD in other organisms. For instance, in filamentous fungi like Epichloë festucae and Neurospora crassa, PLD and its product phosphatidic acid (PA) have been shown to be important for hyphal morphogenesis, growth, and cell fusion[2]. In the context of adrenal steroidogenesis, different phospholipases, including PLD, have been implicated in the production of secondary messengers that modify cellular functions[3]. Additionally, in plants, PLD has been linked to the response to pathogen challenge and is differentially expressed during host-pathogen interactions[4]. This recent study expands on these earlier findings by demonstrating a specific role for PLD in the pathogenicity of a filamentous fungus. By showing how the deletion of TrPLD1 leads to reduced fungal development and lessened disease severity in apples, the study provides valuable insights into potential targets for controlling fungal diseases in crops. It also underscores the complexity of the PLD family of enzymes and their diverse roles across different species and biological contexts. In summary, the research from Gansu Agricultural University has highlighted the critical function of PLD, particularly TrPLD1, in the pathogenicity of Trichothecium roseum. By disrupting the normal function of this enzyme, the researchers were able to reduce the fungus's ability to infect and damage apple fruits. These insights not only deepen our understanding of fungal biology but also pave the way for the development of new strategies to protect crops from fungal diseases.

FruitsBiochemPlant Science

References

Main Study

1) Effects of TrPLDs on the pathogenicity of Trichothecium roseum infected apple fruit.

Published 18th April, 2024

https://doi.org/10.1016/j.fm.2024.104496

Related Studies

2) Phosphatidic acid produced by phospholipase D is required for hyphal cell-cell fusion and fungal-plant symbiosis.

https://doi.org/10.1111/mmi.14480

3) Role of phospholipases in adrenal steroidogenesis.

https://doi.org/10.1530/JOE-16-0007

4) Differential expression of genes encoding Arabidopsis phospholipases after challenge with virulent or avirulent Pseudomonas isolates.

Journal: Molecular plant-microbe interactions : MPMI, Issue: Vol 15, Issue 8, Aug 2002


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