Pseudomonas plantarii

Pseudomonas plantarii is a Gram-negative, aerobic, rod-shaped bacterium classified within the genus Pseudomonas. As a significant phytopathogen, it is responsible for severe infections in various crops, most notably causing bacterial seedling rot in rice (Oryza sativa). It is well-documented in agricultural research due to its capacity to cause significant economic losses in rice-producing regions.

The primary symptom of the disease is the sudden wilting and rot of rice seedlings shortly after germination. Infected plants exhibit chlorosis, stunted growth, and a slimy decay of tissues. In many cases, the pathogen produces toxins that inhibit the development of the root system and the shoot, leading to total seedling mortality and large gaps in the planted rows.

The biology of Pseudomonas plantarii is centered on its survival in contaminated seeds and the surrounding soil environment. During the initial stages of crop growth, bacteria migrate to the seedling tissue. The infection process is facilitated by high humidity, which is characteristic of paddy fields, allowing the pathogen to move rapidly through irrigation water from one plant to another.

Environmental conditions play a critical role in the severity of an outbreak. Warm temperatures ranging from 20 °C to 30 °C are optimal for bacterial proliferation. When combined with excessive irrigation and poor drainage, these conditions allow the pathogen to reach epiphytotic levels, causing severe damage to newly established stands and reducing the overall density of the crop.

Control strategies for this pathogen are primarily preventative. Effective management involves using certified, disease-free seed lots and subjecting the seeds to bactericidal treatments before sowing. Furthermore, maintaining proper field hygiene, such as removing crop debris and managing the water table during the early stages of growth, is essential to minimize the risk of infection and preserve yield potential.