An anther development F-box (ADF) protein regulated by tapetum degeneration retardation (TDR) controls rice anther development

Abstract

In this study, we reported that a F-box protein, OsADF, as one of the direct targets of TDR , plays a critical role in rice tapetum cell development and pollen formation. The tapetum, the innermost sporophytic tissue of anther, plays an important supportive role in male reproduction in flowering plants. After meiosis, tapetal cells undergo programmed cell death (PCD) and provide nutrients for pollen development. Previously we showed that tapetum degeneration retardation (TDR), a basic helix-loop-helix transcription factor, can trigger tapetal PCD and control pollen wall development during anther development. However, the comprehensive regulatory network of TDR remains to be investigated. In this study, we cloned and characterized a panicle-specific expression F-box protein, anther development F-box (OsADF). By qRT-PCR and RNA in situ hybridization, we further confirmed that OsADF expressed specially in tapetal cells from stage 9 to stage 12 during anther development. In consistent with this specific expression pattern, the RNAi transgenic lines of OsADF exhibited abnormal tapetal degeneration and aborted microspores development, which eventually grew pollens with reduced fertility. Furthermore, we demonstrated that the TDR, a key regulator in controlling rice anther development, could regulate directly the expression of OsADF by binding to E-box motifs of its promoter. Therefore, this work highlighted the possible regulatory role of TDR, which regulates tapetal cell development and pollen formation via triggering the possible ADF-mediated proteolysis pathway.

Comparative analysis of microRNA profiles of rice anthers between cool-sensitive and cool-tolerant cultivars under cool-temperature stress

“…Possible miRNA-mediated mechanisms of cool tolerance in rice anthers Tapetum cells in rice anthers are degraded by programmed cell death (PCD) during tetrad to vacuolated pollen stages (Li et al, 2006), and retarded degradation of the tapetum can cause pollen sterility (Li et al, 2006;Li et al, 2015). Pollen sterility in rice plants due to cool-temperature stress is mainly due to tapetum hypertrophy (Imin et al, 2006;Oda et al, 2010).…”

Quantitative trait loci identification and meta-analysis for rice panicle-related traits

“…The F-box gene family has been shown to play an important role in regulating various developmental processes and stress responses. Also, several F-box genes have been characterized to regulate important and diverse physiological processes, such as hormonal response, embryogenesis, seed germination, seedling development, floral organogenesis, lateral root formation, leaf senescence, pathogen resistance, and abiotic stress responses (Ikeda et al 2007;Li et al 2015;Song et al 2012). In MQTL6.2, Os06g11860 is an ethylene-responsive transcription factor (ERF) gene.…”

Identification and gene cloning of a male‐sterile mutant Oswbc11 in rice

“…The tapetum is a specialized layer of cells within the anther and important for the nutrition and development of pollen grains. Genes, UDT1 (Jung et al, ), GAMYB (Liu, Bao, Liang, Yin, & Zhang, ), PTC1 (Li, Yuan et al, ), API5 (Li, Gao et al, ) and TDR (Li et al, ), encode transcription factors and are necessary to regulate pollen grain formation of the tapetum in anther. Exine, the outer pollen wall, consists mainly of sporopollenin and acts as a protective barrier for each pollen grain.…”