Toxic Iguanar — ruling 1

As long as at least one permanent you control is the specified color, the ability will “work” and grant this creature the bonus. Otherwise, it won’t have the bonus.

Toxic Iguanar — ruling 2

Whether Toxic Iguanar has deathtouch matters only when it deals damage (that is, at the point when its combat damage resolves, or at the point when a spell or ability that causes it to deal damage resolves). For example, if your only green permanent is a creature that receives lethal damage at the same time Toxic Iguanar deals damage to a creature, the deathtouch ability will still apply and the creature Toxic Iguanar dealt damage to will be destroyed.

Toxic Iguanar : règles, fonctionnement et interactions (MTG)

Toxic Iguanar is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

This creature has deathtouch as long as you control a green permanent. (Any amount of damage a creature with deathtouch deals to a creature is enough to destroy it.)

How it works : Toxic Iguanar

Original English text — Wizards of the Coast / Scryfall

#1February 1, 2009· Wizards of the Coast
As long as at least one permanent you control is the specified color, the ability will “work” and grant this creature the bonus. Otherwise, it won’t have the bonus.
No other card is named in this ruling.
#2February 1, 2009· Wizards of the Coast
Whether Toxic Iguanar has deathtouch matters only when it deals damage (that is, at the point when its combat damage resolves, or at the point when a spell or ability that causes it to deal damage resolves). For example, if your only green permanent is a creature that receives lethal damage at the same time Toxic Iguanar deals damage to a creature, the deathtouch ability will still apply and the creature Toxic Iguanar dealt damage to will be destroyed.
No other card is named in this ruling.