It has been shown experimentally that OsPHYB interacts with OsPIL15 and phyB mutant plants contain increased levels of OsPIL15 protein compared to wild-type plants. OsPHYB likely targets OsPIL15 for degradation (Xie et al. 2019). Thus, OsPIL15 expression is negatively regulated by Phytochrome B (PHYB), the main light photoreceptor (Xie et al. 2019). The loss-of-function phyB plants and OsPIL15-overexpressing plants have smaller tiller angles (enhanced shoot gravitropism).
