Figure 5.

Main transitions and putative actors for lateral root gravitropism after emergence. PIN1 and AUX1 are expressed throughout the lateral root primordium development and after emergence in the lateral root apex in a pattern close to the one observed in primary root meristem (see text). PIN2 expression is switched on early after lateral root emergence. Between 60 and 72 hag (respectively, 12 and 24 h post-emergence, (a)), phloem connection is established and statoliths appear in the columella. PIN4 and PIN7 expression also begins in lateral root vascular tissues between 48 and 72 hag. Between 72 and 96 hag (respectively, 24 and 48 h post-emergence, (b)), PIN4 and PIN7 expression starts in the lateral root columella while PIN3, which was previously expressed in the same tissues as in the primary root meristem, disappears from the lateral root columella.