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bioRxiv · 10.1101/2020.06.30.180398

Environment-conditioned male fertility of HD-ZIP IV transcription factor mutant ocl4: impact on 21-nt phasiRNA accumulation in pre-meiotic maize anthers

Yadava, P.·Tamim, S.·Zhang, H.·Teng, C.·Zhou, X.·Meyers, B. C.·Walbot, V.
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Abstract

Environment-conditioned genic male sterility is a key strategy used to produce hybrid seeds efficiently in many crops, with the exception of maize. The underlying molecular mechanisms of environment-conditioned sterility are poorly understood. Here, we report a derivative line of the male sterile outer cell layer 4 (ocl4) mutant of maize, in which fertility was restored and perpetuated over several generations, under warm growing conditions. Conditionally fertile ocl4 anthers exhibit the anatomical abnormality of a partially duplicated endothecial layer, just like their sterile counterparts. We profiled the dynamics of phased, small interfering RNAs (phasiRNAs) during pre-meiotic development in fully sterile and various grades of semi-fertile ocl4 anthers. We found that the biogenesis of 21-nt phasiRNAs is largely dependent on Ocl4 at three key steps: (1) production of PHAS precursor transcripts, (2) expression of miR2118 that modulates precursor processing, and (3) accumulation of 21-nt phasiRNAs. We propose that 21-nt reproductive phasiRNAs buffer development under unfavorable environmental conditions and are dispensable under favorable conditions.Competing Interest StatementThe authors have declared no competing interest.View Full Text

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Yadava, P., Tamim, S., Zhang, H., Teng, C., Zhou, X., Meyers, B. C., Walbot, V.. 2020-07-02. Environment-conditioned male fertility of HD-ZIP IV transcription factor mutant ocl4: impact on 21-nt phasiRNA accumulation in pre-meiotic maize anthers. https://doi.org/10.1101/2020.06.30.180398

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