Barry, L. | bioRxiv Science

bioRxiv2024

Root metaxylem area influences drought tolerance and transpiration in pearl millet in a soil texture dependent manner

O_LIPearl millet is a key cereal for food security in drylands but its yield is strongly impacted by drought. We investigated how root anatomical traits contribute to mitigating the effects of vegetative drought stress in pearl millet. C_LIO_LIWe examined associations between root anatomical traits and agronomical performance in a pearl millet diversity panel under irrigated and vegetative drought stress treatments in field trials. The impact of associated anatomical traits on transpiration was assessed using subpanels grown in different soil within a greenhouse. C_LIO_LIIn the field, total metaxylem area was positively correlated with grain weight and its maintenance under drought. In the greenhouse, genotypes with larger metaxylem area grown in sandy soil exhibited a consumerist water use strategy under irrigation, which shifted to a conservative strategy under drought. Water savings was mediated by transpiration restriction under high evaporative demand. This mechanism was dependent on soil hydraulics as it was not observed in peat soil with higher hydraulic conductivity upon soil drying. C_LIO_LIWe propose that water savings under drought, mediated by large metaxylem area and its interaction with soil hydraulics, help mitigate vegetative drought stress. Our findings highlight the role of soil hydraulic properties in shaping plant hydraulics and drought tolerance. C_LI

physiology↗

bioRxiv2023

Characterization of the RBM15 protein binding with XCI-escaping long noncoding RNAs

The RNA binding motif 15 protein (RBM15) plays a critical role in post-transcriptional regulation. Its role in facilitating N6-methyladenosine (m6A) modification, specifically through guiding the writer complex (WTAP METTL13 METTL14) to DRACH sequence motifs, has been demonstrated for several classes of RNA, including long noncoding RNAs (lncRNAs). The structural mechanism that underlies how RBM15 interacts with RNA has yet to be elucidated. In this study, we mined and bioinformatically assessed publicly available genome-wide RNA 2D structural probing and RBP cross-linking and immunoprecipitation data to investigate how RBM15 interacts with RNA, with a focus on lncRNA transcripts. RBM15, which possesses three RNA recognition motifs (RRMs), primarily interacts with stem-loop structured RNA motifs. Structural modeling reveals RRMs 2 and 3 are coaxially stacked in solution; these two RRMs are responsible for driving RBM15s interaction with RNA. We further demonstrate this experimentally with two RNA hairpins, revealing low micromolar binding affinities. Altogether, this work provides insight into the structural mechanism by which RBM15 interacts with RNAs to govern biological function.

biochemistry↗