Genomic and cDNA clones have been isolated for a new gene (PO22) expre
ssed in mature pollen of alfalfa. PO22 represents a single- or low-cop
y gene containing 4 introns, 2 transcriptional start sites, and coding
for a predicted protein of 340 amino acids with no signal peptide and
a coiled coil structure of 39 amino acids near the carboxyl end. The
amino acid sequence of PO22 is 38% identical to that of an early nodul
e-specific gene (ENOD8), also from alfalfa.