Functional analysis of PI-like gene in relation to flower development from bamboo (Bamhusa oldhamii)

Bamboo flowering owns many unique characteristics and remains a mystery. To investigate the molecular mechanisms underlying flower development in bamboo, a petal-identity gene was identified as a PISTILLATA homologue named BoPI from Bambusa oldhamil (bamboo family), Expression analysis showed that BoPI was highly expressed in flower organs and gradually increased during flower development stage, suggesting that BoPI played an important role in flower development. Ectopic expression of BoPI in Arabidopsis caused conversion of sepals to petals. 35S::BoPI filly rescued the defective petal formation in the pi-1 mutant. BoPI could interact with BoAP3 protein in vitro. These results suggested that BoPI regulated flower development of bamboo in a similar way with PI. Besides flower organs, BoPI was also expressed in leaf and branch, which revealed that Boil. may involve in leaf and branch development. Similar to other MIKC-type gene, BoP1 contained the C-terminal sequence but its function was controversial. Ectopic expression of the C-terminal deletion constrict (BoPI-Delta C) in Arabidopsis converted sepals to petals; BoPI-Delta C interacted with BoAP3 on yeast two-hybrid assay, just like the full-length construct. The result implied that the C-terminal sequence may not be absolutely required for organ identity function in the context of BoPI.