Functional analysis of apple stem pitting virus coat protein variants

Area of Science:

• Plant Virology
• Molecular Biology
• Protein Function

Background:

• Viral coat proteins (CPs) are multifunctional, involved in various stages of the viral infection cycle.
• The specific functions of Apple stem pitting virus (ASPV) CPs are not fully understood.
• This study investigates functional diversification among six ASPV CP variants due to sequence diversity.

Purpose of the Study:

• To characterize the biological, serological, pathogenic, and viral suppressor of RNA silencing (VSR) functions of six ASPV CP variants.
• To explore functional diversification driven by sequence variations in ASPV CPs.
• To compare the functions of different ASPV CP variants.

Main Methods:

• Expression of six ASPV CP variants in Escherichia coli and Nicotiana benthamiana.
• Agrobacterium-mediated infiltration (Agroinfiltration) for protein expression and YFP-CP fusion.
• Analysis of serological reactivity, aggregation in planta, biological symptoms, and VSR activity.

Main Results:

• Recombinant ASPV CPs showed varying serological reactivity to anti-ASPV antibodies.
• YFP-ASPV-CP fusions displayed differential aggregation capabilities in N. benthamiana cells.
• ASPV isolates with different CPs induced distinct symptoms in N. occidentalis, while PVX-expressed CPs showed similar symptoms and VSR activity.

Conclusions:

• ASPV CP variants exhibit sequence-dependent differences in aggregation.
• All studied ASPV CP variants possess similar VSR activity when expressed via PVX.
• Functional diversification exists among ASPV CPs, influencing biological symptoms and aggregation.