OsMADS1 Represses microRNA172 in Elongation of Palea/Lemma Development in Rice

Abstract

Specification of floral organ identity is critical for the establishment of floral morphology and inflorescence architecture. Although multiple genes are involved in the regulation of floral organogenesis, our understanding of the underlying regulating network is still fragmentary. MADs-box genes are principle members in the ABCDE model that characterized floral organs. OsMADS1 specifies the determinacy of spikelet meristem and lemma/palea identity in rice. However, the pathway through which OsMADS1 regulates floral organs remains elusive; here, we identified the microRNA172 (miR172) family as possible regulators downstream of OsMADS1. Genetic study revealed that overexpression of each miR172 gene resulted in elongated lemma/palea and indeterminacy of the floret, which resemble the phenotype of osmads1 mutant. On the contrary, overexpression of each target APETALA2 (AP2) genes resulted in shortened palea/lemma. Expression level and specificity of miR172 was greatly influenced by OsMADS1, as revealed by Northern blot analysis and In situ hybridization. Genetically, AP2-3 and AP2-2 over expression rescued the elongation and inconsistent development of the lemma/palea in OsMADS1RNAi transgenic plants. Our results suggested that in rice, OsMADS1 and miR172s/AP2s formed a regulatory network involved in floral organ development, particularly the elongation of the lemma and the palea.

Osa‐miR164a targets OsNAC60 and negatively regulates rice immunity against the blast fungus Magnaporthe oryzae

“…This miRNA was further studied and would be discussed in a separate report. Osa‐miR172 is involved in flowering, palea/lemma development and spikelet determinacy (Zhu et al ., ; Lee et al ., ; Dai et al ., ). Osa‐miR172 was not further pursued due to its association with developmental processes.…”

Genome-Wide Identification and Characterization of the ALOG Domain Genes in Rice

“…The results showed that OsG1 probably functions between OsMADS50 and many other MADS-box genes, such as OsMADS32 , OsMADS18 , OsMADS34 , OsMADS65 , OsMADS5 , OsMADS14 , OsMADS15 , OsMADS1 , OsMADS6 , and OsMADS17 , to specify floral organ identity. Among these MADS-box genes, OsMADS32 regulates floral organ identity in rice, OsMADS1 plays an important role in rice floral organ identity specification and floral meristem determinacy [45, 46, 59, 60], OsMADS1 and OsMADS15 are both required to ensure sexual reproduction in rice [61], and OsMADS34 specifies the identities of floral organs [62, 63]. Based on these results, we propose that OsG1 functions synergistically with or upstream of OsMADS1 , OsMADS15 , OsMADS32 , and OsMADS34 genes to specify the identities of floral organs in rice.…”

Modulation of plant architecture by the miR156f–OsSPL7–OsGH3.8 pathway in rice

“…Anatomical analysis and in situ hybridization were carried out as previously described by Wang et al (2010) and Dai et al (2016) , respectively.…”