Zinc deficiency shows up as yellow mottling between the main veins. Zinc deficiency can cause stunted and twisted foliage.

Zinc is required in very small quantities, but in soils with a high lime content zinc is unavailable to the plant.
The pic above shows zinc deficiency on lemon but the deficiency is also common on grape leaves.

Control
Zinc in an approved chemical product can be applied to the soil or as a foliar spray.