How Friendly Bacteria Help Sesame Plants Fight Harmful Infections

Greg Howard
3rd July, 2024

How Friendly Bacteria Help Sesame Plants Fight Harmful Infections

Sesame (Sesamum indicum)

Photo adapted from: Dr. Alexey Yakovlev / CC BY (Source)

Key Findings

  • In Egypt, sesame plants are severely affected by the fungus Macrophomina phaseolina, causing diseases like damping-off and charcoal rot
  • The study found that Streptomyces violaceoruber and Streptomyces hirsutus significantly reduced these diseases in sesame plants
  • Streptomyces-treated plants showed better growth, higher nutrient content, and increased seed yield and oil concentration compared to untreated and fungicide-treated plants
Sesame is an ancient oil crop that has been cultivated for centuries, serving as a significant source for food, industry, and edible oil worldwide. However, sesame plants are susceptible to various pathogens throughout their growth stages, with Macrophomina phaseolina being one of the most dangerous fungi affecting these plants. A recent study by the Agric. Res. Center investigated the impact of two Streptomyces species, Streptomyces violaceoruber and Streptomyces hirsutus, compared to the widely-used fungicide Topsin-M, on combating damping-off and charcoal rot caused by M. phaseolina and on the growth of sesame plants[1]. The study aimed to explore environmentally friendly alternatives to chemical fungicides, which are increasingly scrutinized due to their adverse effects on the environment and human health[2]. Streptomyces species are soil-dwelling mycelial bacteria known for their biocontrol and plant growth-promoting activities[2][3]. These bacteria produce a plethora of bioactive compounds, including antibiotics and extracellular enzymes, which can inhibit pathogen growth and enhance plant health. The researchers conducted a series of experiments to assess the effectiveness of S. violaceoruber and S. hirsutus in controlling M. phaseolina infections in sesame plants. They compared the results with those obtained using Topsin-M, a commonly used chemical fungicide. The study measured several parameters, including the incidence of damping-off and charcoal rot, plant growth metrics, and overall plant health. The findings revealed that both Streptomyces species significantly reduced the incidence of damping-off and charcoal rot in sesame plants, comparable to the effects of Topsin-M. Additionally, the Streptomyces-treated plants exhibited improved growth metrics, such as increased plant height, root length, and biomass, compared to untreated controls and even Topsin-M treated plants. Streptomyces species exert their beneficial effects through several mechanisms. They produce a wide range of secondary metabolites, including antibiotics, which can directly inhibit pathogen growth[3]. Moreover, they secrete extracellular enzymes that degrade the cell walls of pathogenic fungi, thereby preventing infection[3]. Streptomyces also enhance nutrient availability and uptake in plants by breaking down complex organic materials in the soil, which can further promote plant growth[2]. The study also highlighted the role of Streptomyces in promoting plant health through indirect mechanisms. For instance, Streptomyces can induce systemic resistance in plants, making them more resilient to subsequent pathogen attacks[4]. This is achieved through the production of signaling molecules that trigger plant defense responses. Additionally, Streptomyces can improve soil health by enhancing soil structure and fertility, creating a more conducive environment for plant growth[4]. In conclusion, the study by the Agric. Res. Center demonstrates that Streptomyces violaceoruber and Streptomyces hirsutus are effective biocontrol agents against M. phaseolina in sesame plants, offering a viable and environmentally friendly alternative to chemical fungicides like Topsin-M. These findings align with previous research highlighting the agricultural importance of Streptomyces in biocontrol and plant growth promotion[2][3]. By harnessing the beneficial properties of these soil-dwelling bacteria, farmers can improve crop yields and sustainability, contributing to a more sustainable agricultural future.

AgricultureBiochemPlant Science

References

Main Study

1) Impact of Streptomyces on sesame plants under Macrophomina phaseolina infestation

Published 2nd July, 2024

https://doi.org/10.1186/s41938-024-00801-8

Related Studies

2) Streptomyces: implications and interactions in plant growth promotion.

https://doi.org/10.1007/s00253-018-09577-y

3) The complex extracellular biology of Streptomyces.

https://doi.org/10.1111/j.1574-6976.2009.00206.x

4) New frontiers in agriculture productivity: Optimised microbial inoculants and in situ microbiome engineering.

https://doi.org/10.1016/j.biotechadv.2019.03.010


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