MS23, a master basic helix-loop-helix factor in maize, regulates the birth and maturation of tapetum

A cascade of basic helix-loop-helix transcription factors guide tapetal cell development in maize anthers, using proteins conserved in Arabidopsis and rice but deployed with a distinctive timing. Anthers were dissected and staged to be 1500 μm in length (+/- 100 μm) and samples were compared between mutants and fertile siblings on an Agilent 4x44 custom microarray. Analysis included MS32 which is another basic helix-loop-helix factor that acts later during tapetal differentiation. For each mutant versus fertile sib comparison, 2 biological replicates were used with direct comparisons made between fertile and sterile siblings of the same mutant background.