Question

Dodder can transmit
A.Mycoplasmal diseases
B.Viral diseases
C.Bacterial
D.Both a and b

Answer 1

Hint: Dodder can transmit diseases through the haustoria connected to vascular tissues of two host plants. Dodder connects parasite hyphal tips with that of the cytoplasm of the host cell through plasmodesmata connections. This property is also used for the transfer of useful viruses from one plant to another.

Complete step by step answer:
Dodder is a vine which lives as a parasite on higher plants. It is known as Cuscuta and belongs to the family Convolvulaceae. It derives nutrition from the host plant by forming haustoria connected to vascular tissues of higher plants. Dodder can transmit viruses and mycoplasma through the plasmodesmata connecting parasite’s hyphal tips with the cytoplasm of the host cell. In 1940 Bennett discovered that virus is transmitted from infected to healthy plant through the dodder that was a parasite on both of the plants. Viruses and mycoplasma can easily be transmitted through plasmodesmata connections. This property of transmission is also used to transfer viruses from one host to another. Bacterial diseases cannot be transmitted to cell sap.
Hence option (D) Both (A) and (B) are correct.

Additional Information:
Bacterial causes four types of diseases in plants namely vascular wilt, necrosis, soft rot and tumors. In Black rot, disease bacteria enter through the wounds of plant and infect the entire plant as it travels through water-conducting tissues. In bacterial blight bacterial enters the plants through damaged leaves and small brown spots are seen on leaves. Wilt bacteria is transmitted by an insect.

Note: Dodder is a parasite belonging to family Convolvulaceae. It parasites in higher plants for water and nutrients and it transfers viral and mycoplasmal diseases through plasmodesmata connections of haustoria parasiting two plants.