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An ethylene receptor gene named BoERS1 was cloned from a bamboo (Bambusa oldhamii) cDNA library. The open reading frame of BoERS1 was 1,899 bp and encoded a 632-amino acid protein, which contains the five conserved motifs (H, N, G1, F, and G2 boxes) of the bacterial two-component system histidine kinases and shows high sequence similarity with other ethylene receptors in plants, such as rice and maize. Expression of BoERS1 in bamboo shoots increased with the growth of the emerging shoots. In an in vitro kinase assay, the expressed histidine kinase domain of BoERS1 (BHK) was phosphorylated in the presence of Mn2+, and LC-ESI-MS/MS analysis showed that four amino acids, namely T442, S444, S489, and S503, were phosphorylated. It is interesting to note that S489 and S503 are located in a loop region (L1) that is found only in plant histidine kinase-containing enzymes. The identification of multiple phosphorylation sites on BoERS1 provides a new avenue for future structure–function studies of the ethylene receptor protein family.

A vacuolar type β-d-fructofuranosidase (Osβfruct3) was cloned from etiolated rice seedlings cDNA library. It encodes an open reading frame of 688 residues. The deduced amino acid sequence had 58% identity to the vacuolar type β-d-fructofuranosidase of maize (Ivr1). Osβfruct3 exists as a single copy per genome. Northern analyses showed that Osβfruct3 undergoes organ-specific expression and is involved in the adjustment of plant responses to environmental signals and metabolizable sugars. Osβfruct3 was also heterologously expressed in Pichia pastoris. The recombinant proteins were confirmed to be a vacuolar type β-d-fructofuranosidase.