 BID-1 is a nodule-specific signal-peptid peptidase that is essential for proper functioning of the endoplasmic reticulum, ER. It is required for the formation of close associations between the ER and symbiosomes, which are intracellular bacterial structures that form during legume rhizobium symbiosis. This allows for efficient transport of proteins from the ER into the symbiosomes, where they can be used for nitrogen fixation. Without BID-1, the ER cannot properly adapt to the presence of symbiosomes, resulting in impaired protein secretion and ultimately, symbiosome differentiation. This article was authored by Jian Yang, Niozhai, Yu Hui Chen, and others.