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SUMMARY The anther‐enriched phased, small interfering RNAs (phasiRNAs) play vital roles in sustaining male fertility in grass species. Their long non‐coding precursors are synthesized by RNA polymerase II and are likely regulated by transcription factors (TFs). A few putative transcriptional regulators of the 21‐ or 24‐nucleotide phasiRNA loci (referred to as21‐or24‐PHASloci) have been identified in maize (Zea mays), but whether any of the individual TFs or TF combinations suffice to activate anyPHASlocus is unclear. Here, we identified the temporal gene coexpression networks (modules) associated with maize anther development, including two modules highly enriched for the21‐or24‐PHASloci. Comparisons of these coexpression modules and gene sets dysregulated in several reported male sterile TF mutants provided insights into TF timing with regard to phasiRNA biogenesis, including antagonistic roles for OUTER CELL LAYER4 and MALE STERILE23.Trans‐activation assays in maize protoplasts of individual TFs using bulk‐protoplast RNA‐sequencing showed that two of the TFs coexpressed with21‐PHASloci could activate several 21‐nucleotide phasiRNA pathway genes but not transcription of21‐PHASloci. Screens for combinatorial activities of these TFs and, separately, the recently reported putative transcriptional regulators of24‐PHASloci using single‐cell (protoplast) RNA‐sequencing, did not detect reproducible activation of either21‐PHASor24‐PHASloci. Collectively, our results suggest that the endogenous transcriptional machineries and/or chromatin states in the anthers are necessary to activate reproductivePHASloci.
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Tasselyzer, a machine learning method to quantify maize anther exertion, based on PlantCV
SUMMARY Maize anthers emerge from male‐only florets, a process that involves complex genetic programming and is affected by environmental factors. Quantifying anther exertion provides a key indicator of male fertility; however, traditional manual scoring methods are often subjective and labor‐intensive. To address this limitation, we developedTasselyzer— an accessible, cost‐effective, and time‐saving method for quantifying maize anther exertion. This image‐based program uses the PlantCV platform to provide a quantitative assessment of anther exertion by capturing regional differences within the tassel based on the distinct color of anthers. We applied this method to 22 maize lines with six genotypes, showing high precision (F1score > 0.8). Furthermore, we demonstrate that customizing the parameters to assay a specific line is straightforward and practical for enhancing precision in additional genotypes. Tasselyzer is a valuable resource for maize research and breeding programs, enabling automated and efficient assessments of anther exertion.
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- Award ID(s):
- 2445607
- PAR ID:
- 10573020
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 121
- Issue:
- 4
- ISSN:
- 0960-7412
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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