Sorry if I was a bit snappy there then. It seemed improbable even if it were earlier though given this is the 25th Anniversary for both sales, even if development was shorter back then they would've likely had too little time to really take inspiration from one another.
Here's the actual quote:
From Replay: The History of Video Games by Tristan Donovan, p.162:
"But not everyone in the Japanese game business was impressed by the creations of Horii and Sakaguchi. Nintendo, despite its involvement with Mother, was particularly lukewarm to the genre. Yamauchi described role-playing games as being for "depressed gamers" who sit in dark rooms, while Miyamoto professed to a "fundamental dislike" of their emphasis on pre-defined stories and level-based advancement. Not that this stopped Miyamoto from raiding the genre for inspiration. His 1986 game The Legend of Zelda adapted many of the conventions of role-playing into an action game format. The concept of character development, for example, was reinvented as extra abilities or weapons that players obtained as they progressed through the game."
This paragraph is after one that explains how Horii wanted to make a Japanese, simpler alternative to games such as Ultima and Wizardry (both of which are discussed about earlier in the book) and followed by the story of the craze around Dragon Warrior III in Japan. Because the paragraph started by opposing Miyamoto to what Horii and Sakaguchi made, that's why I made this mistake.
By the way, this book is wonderful, I highly recommend it to anyone who is interested in the history of video games. It's way more complete than Kent's Ultimate History of Video Games, and it covers much more too, as it was published later...