Vascular wilts are wide spread and destructive plant diseases. The symptoms of this disease are primarily caused by the clogging of

Concept:

• The disease is defined as the dysfunction of normal physiological function of plants caused by abiotic and biotic factors. 
• Pathogen is the biotic factor that causes diseases in plants.
• Based on their effect on plants, pathogens in plants are classified into three types:
  1. Necrotrophy: in this case, plant cells are killed
  2. Biotrophy: in this case plant cells are alive
  3. Hemibiotrophy: in this case, plant cells are initially alive but get killed later.
• Disease-causing pathogens can be bacteria, fungi, or viruses. 
• Plant defense against the pathogen can be classified into two types:
  1. Constitutive - this includes many barriers that are always present and prevent the entry of pathogens, This includes cell wall, epidermal cuticles, bark, thorns, etc. 
  2. Inducible - this response is elicited when a pathogen attracts the plant. It includes toxic chemicals, pathogen-degrading enzymes, apoptosis, and systemic resistance.

Explanation:

• Vascular wilt is a plant disease caused by pathogenic fungi or bacteria.
• This pathogen enters the water-conducting vessels of the vascular bundle.
• After entering the vascular tissue, it proliferates in the vascular tissue, thereby disrupting water and minerals transport.
• Symptoms include wilting and then ultimately death of the leaves, which is followed by death of the plant or serious impairment of the plant function.

Hence, the correct answer is option 1.