Biology subjects

Best, N. B.

Publications and source records attributed to Best, N. B..

5 recordsLinked to original sources

bioRxiv2025

Recessive antimorph alleles reveal novel functions of the OPAQUE1 myosin XI in maize

Ideal plant architecture optimizes canopy structure and increases grain yield in maize. However, its underlying genetic mechanisms remain poorly characterized. Two recessive, EMS-induced maize mutants were identified that have reduced stature, opaque kernels, and abnormal subsidiary cell division, and are allelic to opaque1 (o1). These two new missense alleles, o1-2995 and o1-tan62, unlike the loss-of-function alleles previously identified, generate O1 protein but paradoxically generate more severe morphological defects. These defects include reduced internode elongation and partial suppression of excessive tassel and ear branching in ramosa1 (ra1), ra2, and ra3 mutants. We show that o1-2995 and o1-tan62 are novel alleles of o1, and play a role in plant growth via internode elongation, subsidiary cell division positioning, leaf patterning, inflorescence development, and overall plant architecture.

plant biology↗

bioRxiv2025

Lead, a toxic metal, alters auxin-mediated root growth and gravitropic responses in maize and Arabidopsis

Toxic metal contamination in the environment is pervasive and of significant concern due to its high abundance in agricultural lands across the globe. Future engineering of plants tolerant to toxic metals requires a detailed understanding of plant responses to these toxins, which are currently poorly understood. We discovered that, among four toxic metals, lead (Pb) targets conserved cellular and developmental processes in evolutionary diverse plant systems - the model plant Arabidopsis thaliana and crop plant Zea mays. This study shows that Pb increases the phytohormone auxin, which in turn inhibits cell cycle progression to inhibit root growth and alters root gravitropic responses. Both root growth and gravitropic responses are critical for soil exploration, which is required for plants to live and thrive in harsh environments.

plant biology↗

bioRxiv2024

Conservation and diversification of genes regulating brassinosteroid biosynthesis and signaling

Brassinosteroids (BRs) are important regulators that control myriad aspects of plant growth and development including biotic and abiotic stress responses, such that modulating BR homeostasis and signaling presents enormous opportunities for plant breeding and crop improvement. Enzymes and proteins involved in the biosynthesis and signaling of BRs are well understood from molecular genetics and phenotypic analysis in Arabidopsis thaliana; however, knowledge of molecular function of these genes in other plant species, especially cereal crop plants, is highly limited. In this manuscript, we comprehensively review functional studies of BR genes in Arabidopsis, maize, rice, Setaria, Brachypodium, and soybean to identify conserved and diversified functions across plant species, and to highlight cases where additional research is in order. We performed phylogenetic analysis of gene families known to be involved in biosynthesis and signaling of BRs and re-analyzed publicly available transcriptomic data. Gene trees coupled to expression data provide a useful guide to supplement future research on BRs in these important crop species, such as to allow researchers to identify genes to target through gene editing techniques to perform BR-related functional studies.

genetics↗

bioRxiv2020

Mutation of the nuclear pore complex component, aladin1, disrupts asymmetric cell division in Zea mays (maize)

The nuclear pore complex (NPC) regulates the movement of macromolecules between the nucleus and cytoplasm. Dysfunction of many components of the NPC results in human genetic diseases, including triple A syndrome (AAAS) as a result of mutations in ALADIN. Here we report a nonsense mutation in the maize ortholog, aladin1 (ali1-1), at the orthologous amino acid residue of an AAAS allele from humans, alters plant stature, tassel architecture, and asymmetric divisions of subsidiary mother cells (SMCs). Crosses with the stronger nonsense allele ali1-2 identified complex allele interactions for plant height and aberrant SMC division. RNA-seq analysis of the ali1-1 mutant identified compensatory transcript accumulation for other NPC components as well as gene expression consequences consistent with conservation of ALADIN1 functions between humans and maize. These findings demonstrate that ALADIN1 is necessary for normal plant development, shoot architecture, and asymmetric cell division in maize.

genetics↗

bioRxiv2017

Phytohormone Inhibitor Treatments Phenocopy Brassinosteroid And Gibberellin Dwarf Mutant Interactions In Maize

Phytohormone biosynthesis produces metabolites with profound effects on plant growth and development. Modulation of hormone levels during developmental events, in response to the environment, by genetic polymorphism, or by chemical application can reveal the plant processes most responsive to a phytohormone. In many cases, chemical inhibitors are applied and the levels of specific phytohormones are measured to determine if, and which, phytohormone is affected by a molecule. In many cases, the sensitivity of biochemical testing has determined multiple pathways affected by a single inhibitor. Genetic studies are not subject to this problem, and a wealth of data about the morphological impacts of hormone biosynthetic inhibition has accumulated through the study of enzyme mutants. We previously identified a complex interplay between brassinosteroid (BR) and gibberellin (GA) in maize, where the interdependence of the two differs dependent on the developmental context. We found that: GA is required for loss of BR to induce retained pistils in the tassel florets (POPIT); BR is required for the loss of GA to induce tiller outgrowth; BR and GA are additive for plant height; BR has no effect on the induction of anther retention in ear florets of GA mutants. In this work, we sought to assess the specificity of three triazole inhibitors of cytochrome P450s by determining their abilities to recapitulate the phenotype of double mutants. The GA biosynthetic inhibitors uniconazole (UCZ) and paclobutrazol (PAC) were applied to the BR biosynthetic mutant na2 and all double mutant phenotypes were recovered in the UCZ treatment. PAC was unable to suppress the retention of pistils in the tassels of nana plant2 (na2) mutant plants. The BR biosynthetic inhibitor propiconazole (PCZ) suppressed tiller outgrowth in the GA biosynthetic mutant dwarf5 (d5). All treatments were additive with genetic mutants for effects on plant height. Due to additional measurements done here but not in previous studies of the double mutants, we detected new interactions between GA and BR biosynthesis affecting plastochron index and tassel branching. These experiments, a refinement of our previous model, and a discussion of the extension of this type of work are presented.

plant biology↗