Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/243907

The basis of accumulation differences in plant 21-nt reproductive phasiRNAs, and their cis-directed activity

Tamim, S.·Cai, Z.·Mathioni, S.·Zhai, J.·Teng, C.·Zhang, Q.·Meyers, B. C.
View original source ↗Export metadata ↓

Abstract

O_LIPost-transcriptional gene silencing in plants results from independent activities of diverse small RNA types. In anthers of grasses, hundreds of loci yield non-coding RNAs that are processed into 21- and 24-nt phased small interfering RNAs (phasiRNAs); these are triggered by miR2118 and miR2275.\nC_LIO_LIWe characterized these \"reproductive phasiRNAs\" from rice panicles and anthers across seven developmental stages. Our computational analysis identified characteristics of the 21-nt reproductive phasiRNAs that impact their biogenesis, stability, and potential functions.\nC_LIO_LIWe demonstrate that 21-nt reproductive phasiRNAs can function in cis to target their own precursors. We observed evidence of this cis regulatory activity in both rice (Oryza sativa) and maize (Zea mays). We validated this activity with evidence of cleavage and a resulting shift in the pattern of phasiRNA production.\nC_LIO_LIWe characterize biases in phasiRNA biogenesis, demonstrating that the Pol II-derived \"top\" strand phasiRNAs are consistently higher abundance than the bottom strand. The first phasiRNA from each precursor overlaps the miR2118 target site, and this impacts phasiRNA accumulation or stability, evident in the weak accumulation of this phasiRNA position. Additional influences on this first phasiRNA duplex include the sequence composition and length, and we show that these factors impact Argonaute loading.\nC_LI

Source connections

Explore related subjects

plant biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Tamim, S., Cai, Z., Mathioni, S., Zhai, J., Teng, C., Zhang, Q., Meyers, B. C.. 2018-01-07. The basis of accumulation differences in plant 21-nt reproductive phasiRNAs, and their cis-directed activity. https://doi.org/10.1101/243907

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Photosynthesis-derived carbohydrate supply sustains CuCl2-induced phytoalexin production in rice leaves

Phytoalexins are antimicrobial metabolites whose biosynthesis is triggered by signaling activated by both biotic and abiotic elicitors, but the physiological conditions that sustain their production remain poorly understood. Here, we examined how light and carbohydrate availability affect CuCl2-induced production of diterpenoid (phytocassanes and momilactones) and flavonoid (sakuranetin) phytoalexins in rice (Oryza sativa L.) leaf disks. Darkness strongly suppressed both the accumulation of all three phytoalexin groups and the induction of their biosynthetic genes. In darkness, endogenous sucrose, glucose, and fructose declined to 3%-8% of the levels in the light, whereas early accumulation of jasmonic acid and jasmonoyl-L-isoleucine (JA-Ile) was not detectably reduced. Exogenous sucrose restored phytoalexin accumulation in darkness in a dose-dependent manner, together with the expression of the suppressed biosynthetic genes, whereas equimolar mannitol had no effect. Glucose also restored sakuranetin accumulation in darkness but only partially restored diterpenoid accumulation, whereas the glucose analog 2-deoxy-D-glucose did not, and it suppressed CuCl2-induced accumulation in the light in a dose-dependent manner. In the light, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), an inhibitor of photosynthetic electron transport, depleted soluble sugars and suppressed phytoalexin accumulation, and sucrose reversed this suppression. Sugars alone induced little phytoalexin accumulation, indicating that carbohydrates act permissively rather than as elicitors. Diterpenoid phytoalexins depended more strongly on light than sakuranetin, yet both classes depended on carbohydrate availability. These results indicate that photosynthesis-derived carbohydrate supply sustains elicitor-induced phytoalexin production in rice leaves and largely accounts for its light dependence.

plant biology↗
bioRxiv2026

Transcriptome analysis provides insights into candidate genetic regulators of birch response to salt stress

Abstract Background: Soil salinization is a worldwide matter of concern and can result in a series of agricultural and ecological problems. Previous transcriptome data have shown genetic regulatory mechanisms of salt stress response in a salt-tolerant species of Betula halophila and a salt-sensitive species of B. platyphylla, but comparative analysis of transcriptional changes in the the two species remains limited. Aims: We compared gene expression in leaves of B. halophila and leaves and roots of B. platyphylla. Methods: Differentially expressed genes (DEGs) were identified after 24 h of salt stress, followed by Gene Ontology enrichment and gene regulatory network (GRN) construction. Selected DEGs were examined by quantitative real-time PCR (RT-qPCR). Results: Compared with 0 h, 956 DEGs were found in B. halophila leaves (BHLeaf), 2,955 in B. platyphylla leaves (BPLeaf), and 3,827 in B. platyphylla roots (BPRoot). BHLeaf DEG expression patterns were similar to those of BPRoot. DEGs from BHLeaf and BPRoot were enriched in cell wall organization or biogenesis, whereas hormone biosynthesis and signaling genes were altered mainly in B. platyphylla. RT-qPCR showed that selected DEGs were induced by 200 mM NaCl for 24 h in B. platyphylla. Conclusions: Our work uncovered genetic mechanisms of salt stress response commonly and uniquely occurring in two birch species and provides resources for breeding salt-tolerant birch.

plant biology↗
bioRxiv2026

Minimal requirements and evolution of polar membrane targeting in the land plant SOSEKI protein family

Accurate spatial distribution of polar proteins is essential for cell function, but mechanisms underlying polar protein targeting in plants are poorly understood. Here, we dissect the molecular mechanisms underlying the polar targeting of the SOSEKI1 (SOK1) protein in Arabidopsis thaliana. Using extensive mutagenesis and truncation analyses of the polarity domain, we mapped the minimal polarity fragment necessary and sufficient for stable polar targeting to a 25-amino-acid region. This region likely forms an amphipathic helix, and mutations reveal that both its polar and apolar faces are essential for membrane association and polarity. Using phylogenetic analysis, we reconstruct the evolutionary history of the minimal polar targeting region across land plants. Using cross-species expression and protein localization, we infer the ancestral polar SOK localization pattern and show how it remained remarkably conserved, only to diversify upon gene duplication. This work identifies a polar targeting peptide in plants, reveals a mechanism for polar membrane targeting of a plant protein family, and demonstrates both conservation and diversification within this family.

plant biology↗