50nl, AJo on dry Axx flop

villian is 20/8 thru 35 hands

whats a standard line here?

Full Tilt Poker
No Limit Holdem Ring game
Blinds: $0.25/$0.50
8 players
Converter

Stack sizes:
UTG: $43.45
hero: $52.20
MP1: $27
MP2: $39.65
CO: $141.95
Button: $47.75
SB: $20.25 [sitting out]
BB: $85.65

Pre-flop: (8 players) hero is UTG+1 with J A
UTG folds, hero raises to $2, MP1 calls, 5 folds.

Flop: 7 A 3 ($4.75, 2 players)
hero ...

...bets 4$.

Almost always bets, once a blue moon check it.

whats the plan if called?

bet again