Which characteristic is true of fastidious vascular bacteria?

Fastidious vascular bacteria are known for being rod-shaped and gram-negative. This classification is important because the rod shape is a common morphological characteristic of many bacterial species, and the gram-negative classification indicates the structural integrity of their cell wall. Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane containing lipopolysaccharides, which can influence their pathogenicity and require specific conditions for growth. The nature of these bacteria often makes them more complex to culture and manage in agricultural settings, as they may require specialized growth media and conditions due to their fastidious growth requirements.

The other characteristics listed do not accurately describe fastidious vascular bacteria. They are not typically spore-forming or heat-resistant, which would indicate traits associated with different types of bacteria. Additionally, being filamentous or having non-gram staining properties does not apply to this group; fastidious vascular bacteria cannot be classified as such due to their distinct cellular structure and biochemical requirements. Round-shaped, gram-positive bacteria refer more to other bacterial groups and do not encompass the defining features of fastidious vascular bacteria.