What do plants express in response to an infectious disease?

Plants exhibit a variety of symptoms in response to infectious diseases, which can include changes in coloration, wilting, stunted growth, and other visible indicators. These symptoms play a crucial role in diagnosing the cause of the disease. They allow researchers, agronomists, and gardeners to identify specific pathogens and understand the nature of the disease affecting the plant. Observing the symptoms can lead to targeted interventions and management strategies tailored to the specific issue at hand.

The other options do not fully capture the complex nature of plant responses to disease. While physical damage and lack of growth can occur, they do not specifically aid in diagnosing the disease. Similarly, while plants may react chemically to certain stressors, these reactions primarily aim to strengthen the plant's defenses rather than neutralizing toxins. Finally, while some plants can develop resistance mechanisms that limit the spread of certain pathogens, these do not universally halt the disease, as many pathogens can still impact the plant to varying degrees.