Desulfovibrionales

Desulfovibrionales is a group of sulfate-reducing bacteria that, while not direct primary pathogens in the traditional sense, play a critical role in creating a phytopathogenic environment. These microorganisms are obligate anaerobes that reduce sulfates to hydrogen sulfide during their metabolism.

These bacteria affect a wide range of agricultural crops, especially those grown in heavy, waterlogged, or marshy soils. The most vulnerable are the root systems of cereals, vegetables, and fruit crops that suffer from oxygen deficiency in the rhizosphere.

Symptoms of their impact include stunted growth, yellowing, and gradual root decay. In soil where Desulfovibrionales are active, a characteristic smell of hydrogen sulfide (rotten eggs) is often present, and the soil acquires a dark gray or black color due to the formation of iron sulfides.

Conditions for their mass development include excessive moisture, lack of drainage, soil compaction, and high levels of organic debris that create anaerobic pockets. These bacteria multiply actively where normal gas exchange between the soil and the atmosphere is restricted.

• Improving field drainage systems.
• Regular soil tilling for better aeration.
• Proper crop rotation and avoiding over-irrigation.
• Use of oxidative biological agents.
• Monitoring soil pH and organic matter content.

The damage caused by Desulfovibrionales is due to the hydrogen sulfide they release, which is toxic to plant roots. This leads to impaired nutrient uptake, weakened plant immunity, and increased susceptibility to colonization by secondary pathogens, such as those causing various root rots.