Zea mays subsp. mays Transcriptome or Gene expression

Maize anthers, the male reproductive floral organs, express two classes of phased, small interfering RNAs (phasiRNAs). RNA profiling from ten sequential cohorts of staged maize anthers plus mature pollen revealed that 21-nt phased siRNAs (21-phasiRNAs) from 463 loci appear abruptly after germinal and initial somatic cell fate specification and then diminish, while 24-nt phased siRNAs (24-phasiRNAs) from 176 loci coordinately accumulate during meiosis and persist as haploid gametophytes differentiate into pollen. RNA sequencing of anther developmental mutants, together with in situ RNA hybridization detection of phasiRNA biogenesis factors, demonstrated that 21-phasiRNAs and 24-phasiRNAs are independently regulated. Furthermore, 21-phasiRNAs require epidermal cells while 24-phasiRNAs require functional tapetal cells. Maize phasiRNAs and mammalian PIWI-interacting RNAs (piRNAs) illustrate convergent evolution of small RNAs to support male reproduction. Overall design: Examination of maize phasiRNAs by high throughput sequencing for RNA-seq, small RNA and PARE profiling.