A researcher obtained a loss-of-function mutant of plasmodesmata protein synaptotagmin (SYTA) in Arabidopsis and infected the plants with cabbage leaf curl virus (CaLCuV). The following statements represent possible outcomes of the above experiment:

A. The CaLCuV infection will be slower in the mutant plants.
B. The mutant plants will be completely resistant to the viral infection.
C. The endocytic recycling pathway in the infected cells will be compromised in the mutant plants.
D. The disease symptoms will be more severe in the mutant plants.

Which one of the following options represents all correct statement(s)?

Correct option is A

Explanation:

• A is correct: SYTA is involved in plasmodesmatal trafficking; loss of function slows viral movement, so infection progression slows in mutants.

• B is incorrect: Mutant plants are not completely resistant; viral infection is slowed but not blocked.

• C is correct: SYTA functions in endocytic recycling; mutants compromise this pathway affecting virus trafficking.

• D is incorrect: Disease symptoms are usually less severe or delayed in mutants due to slowed viral spread.

Hence, only statements A and C are correct.

Information Booster:

• Synaptotagmin (SYTA) is a key regulator of plasmodesmatal trafficking and endocytic recycling in plants, essential for intercellular communication and viral movement.

• Loss-of-function mutants show impaired viral spread, slowing disease progression but rarely confer full resistance.

• Endocytic recycling is critical for membrane protein turnover and trafficking, including viral proteins.

Additional Information on Incorrect Options:

• Complete resistance (B) is not observed as viruses can use alternative pathways.

• Increased disease severity (D) contradicts the known effect of slowed virus spread in SYTA mutants.