A transposon surveillance mechanism that safeguards plant male fertility during stress

Abstract

Although plants are able to withstand a range of environmental conditions, spikes in ambient temperature can impact plant fertility causing reductions in seed yield and significant economic losses 1,2 . Therefore, understanding the precise molecular mechanisms that underpin plant fertility under environmental constraints is critical to safeguard future food production 3 .Here, we identified two Argonaute-like proteins whose activities are required to sustain male fertility in maize plants under high temperatures. We found that MALE-ASSOCIATED ARGONAUTE 1 and 2 (MAGO1 and MAGO2) associate with temperature-induced phased secondary small RNAs in pre-meiotic anthers and are essential to control the activity of

Repression of CHROMOMETHYLASE 3 prevents epigenetic collateral damage in Arabidopsis

“…Complex mechanisms are required to specifically silence mutagenic TEs rather than endogenous genes ( Antunez-Sanchez et al, 2020 ; Deng et al, 2016 ; Lee et al, 2021 ; Lister et al, 2008 ; Papareddy et al, 2020 ; Saze and Kakutani, 2011 ; Williams et al, 2015 ; Zhang et al, 2020 ). Mechanisms regulating epigenome homeostasis are of paramount importance during Arabidopsis embryogenesis due to highly dynamic cell cycle and transcriptional activities, as well as the establishment of cell lineages that will produce all future cell types including the gametes.…”

Spatiotemporal regulation and roles of reproductive phasiRNAs in plants

“…Thereafter, DCL4 or DCL3b/5 processes these dsRNAs into 21-nt or 24-nt phasiRNAs (Song et al, 2012a;Teng et al, 2020). Finally, AGOs bind to the phasiRNAs and mediate silencing (Komiya et al, 2014;Lee et al, 2021).…”

License to Regulate: Noncoding RNA Special Agents in Plant Meiosis and Reproduction

“…Rice shows recombination-dependent chromosome pairing, so one possibility is that the lack of synapses in the mel1 mutant is a consequence of an almost complete absence of DSBs. Two additional AGO proteins, MAGO1 and MAGO2, have been recently identified in maize; these proteins are involved in the 21-nt reproductive phasiRNA pathway and accumulate mostly in anther epidermal cells and in developing meiocytes (Lee et al, 2020).…”

“…Therefore, the function of 21-nt premeiotic phasiRNAs may be to eliminate the expression of specific gene categories at the onset of meiosis (Figure 2; Zhang et al, 2020a). On the other hand, a subclass of 21-nt miR2118-dependent phasiRNAs in maize was shown to be involved in male germline retrotransposon silencing under heat stress conditions (Lee et al, 2020). Inactivation of this pathway leads to male sterility at elevated temperatures, which is due to extensive transposon activation.…”

“…New techniques for isolating PMCs are based on microdissection (Chen and Retzel, 2013); however, in the case of grasses, flow cytometry is also successfully used, which significantly improves the throughput (Chang et al, 2018). Johnson et al, 2009;Ding et al, 2012a;Zhou et al, 2012;Zhai et al, 2015;Lee et al, 2020;Fan et al, 2016 Johnson et al, 2009;Zhai et al, 2015;Dukowic-Schulze et al, 2016;Fei et al, 2016;Xia et al, 2019;Zhang et al, 2020b Anther development lncRNA and siRNA O. sativa Long-day-specific male-fertility-associated RNA (LDMAR) is necessary for anther and pollen development. A specific siRNA named Psi-LDMAR has been associated with regulating levels of LDMAR transcript by targeting RdDM to its promoter region.…”