Does deathtouch work with trample to assign only 1 damage to each blocker?

Normally, a trample creature must assign "lethal damage" to each blocker before it can assign any damage to the defending player or planeswalker (CR 702.19b). "Lethal damage" is defined as damage equal to the blocker's toughness minus any damage already marked on it (CR 702.2c, 702.19b).

Deathtouch changes the calculus: any amount of damage dealt by a source with deathtouch is considered lethal (CR 702.2c). The rules explicitly state that when determining if damage is lethal for the purpose of trample, you take deathtouch into account (CR 702.19b). This means 1 damage from a deathtouch attacker satisfies the lethal-damage requirement for each blocker, no matter how high that blocker's toughness is.

So the attacker must assign at least 1 damage to each blocker, and all remaining combat damage may be assigned to the defending player (or planeswalker). This is one of the most powerful damage-assignment combinations in the game.

Example: You attack with a 5/5 deathtouch, trample creature. Your opponent blocks with a 4/4. You assign 1 damage to the 4/4 (lethal because of deathtouch) and the remaining 4 damage tramples through to the defending player. The 4/4 will also be destroyed at end of combat due to the 1 damage being lethal.

Note: if multiple creatures are blocking, you must still assign at least 1 damage to each individual blocker before the rest can trample through (CR 509.2, 702.19b).