。
The price of rice is going up again.
Literal
Rice's price [subject-が] again rising is.
再び ('again') paired with 上がっている ('is rising') describes a renewed, ongoing price increase. 米の値段 is 'the price of rice.' The ~ている here gives the change-in-progress reading rather than a resulting state — a useful contrast for learners working through ~ている's many shades of meaning.