Biology subjects

Herrera-Estrella, L. R.

Publications and source records attributed to Herrera-Estrella, L. R..

4 recordsLinked to original sources

bioRxiv2021

ROOT PENETRATION INDEX 3, a major quantitative trait locus (QTL) associated with root system penetrability in Arabidopsis.

Soil mechanical impedance precludes root penetration, confining root system development to shallow soil horizons where mobile nutrients are scarce. Using a two-phase-agar system, we characterized Arabidopsis thaliana responses to low and high mechanical impedance at three root penetration stages. We found that seedlings whose roots fail to penetrate agar barriers show drastic changes in shoot and root morphology, while those capable of penetrating have only minor morphological effects. The assessment of 21 Arabidopsis accessions revealed that primary root penetrability (PRP) varies widely among accessions. To search for quantitative trait loci (QTLs) associated to root system penetrability, we evaluated a recombinant inbred population (RIL) derived from Landsberg erecta (Ler-0, with a high PRP) and Shahdara (Sha, with a low PRP) accessions. QTL analysis revealed a major-effect QTL localized in chromosome 3 (q-RPI3), which accounted for 29.98% (LOD = 8.82) of the total phenotypic variation. Employing an introgression line (IL-321), with a homozygous q-RPI3 region from Sha in the Ler-0 genetic background, we demonstrated that q-RPI3 plays a crucial role in root penetrability. This multiscale study revels new insights into root plasticity during the penetration process in hard agar layers, natural variation and genetic architecture behind primary root penetrability in Arabidopsis. HighlightWe found a wide natural variation in the capacity of Arabidopsis accessions to penetrate hard agar layers. Using a Ler-0 x Sha recombinant inbred population, a major-effect QTL (q-RPI3) strongly associated with root penetrability of compact agar layers was identified.

plant biology↗

bioRxiv2021

Viability markers for determination of desiccation tolerance and critical stages during dehydration in Selaginella species

Plants can tolerate some degree of dehydration but below a threshold of water content most plants die. However, some species display specific physiological, biochemical, and molecular responses that allow survival to desiccation. Some of these responses are activated at critical stages during water loss and could represent the difference between desiccation tolerance (DT) and death. Here, we report the development of a simple and reproducible system to determine DT in Selaginella species. This system is based on the use of excised tissue (explants), exposed to a dehydration agent inside small containers, rather than whole plants making it faster, better controlled, and potential use under field conditions. We also report that the triphenyltetrazolium chloride test is a simple and accurate assay to determine tissue viability. The explant system is particularly useful to identify critical points during the dehydration process and was applied to identify novel desiccation-tolerant Selaginella species. Our data suggest that desiccation-sensitive Selaginella species have a change in viability when dehydrated to 40% RWC, indicating the onset of a critical condition at this water content. Comparative studies at these critical stages could provide a better understanding of DT mechanisms and unravel insights into the key responses to survive desiccation. HighlightIn this article, we developed a simple and efficient system to determine desiccation tolerance and critical stages during the dehydration process in Selaginella that can be applied to other plant species.

plant biology↗

bioRxiv2020

Development and cell cycle dynamics of the root apical meristem in the fern Ceratopteris richardii

Ferns are a representative clade in plant evolution although underestimated in the genomic era. Ceratopteris richardii is an emergent model for developmental processes in ferns, yet a complete scheme of the different growth stages is necessary. Here, we present a developmental analysis, at the tissue and cellular levels, of the first shoot-borne root of Ceratopteris. We followed early stages and emergence of the root meristem in sporelings. While assessing root growth, the first shoot-borne root ceases its elongation between the emergence of the fifth and sixth roots, suggesting Ceratopteris roots follow a determinate developmental program. We report cell division frequencies in the stem cell niche after detecting labeled nuclei in the root apical cell (RAC) and derivatives after 8 hours of exposure. These results demonstrate the RAC has a continuous mitotic activity during root development. Detection of cell cycle activity in the RAC at early times suggests this cell acts as a non-quiescent organizing center. Overall, our results provide a framework to study root function and development in ferns and to better understand the evolutionary history of this organ. Summary StatementIn the Ceratopteris root, the apical cell and its derivatives have a high division frequency, suggesting the apical cell acts as a non-quiescent organizing center in the stem cell niche.

developmental biology↗

bioRxiv2016

Malate-dependent Fe accumulation is a critical checkpoint in the root developmental response to low phosphate

Low phosphate (Pi) availability constrains plant development and crop production in both natural and agricultural ecosystems. When Pi is scarce, modifications of root system architecture (RSA) enhance soil exploration ability and can lead to an increase in Pi uptake. In Arabidopsis, an iron-dependent determinate developmental program that induces premature differentiation in the root apical meristem (RAM) begins when the root tip contacts low Pi media, resulting in a short-root phenotype. However, the mechanisms that enable the regulation of root growth in response to Pi-limiting conditions remain largely unknown. Cellular, genomic and transcriptomic analysis of low-Pi insensitive mutants revealed that the malate-exudation related genes SENSITIVE TO PROTON RHIZOTOXICITY (STOP1) and ALUMINUM ACTIVATED MALATE TRANSPORTER 1 (ALMT1) represent a critical checkpoint in the root developmental response to Pi starvation in Arabidopsis thaliana.

plant biology↗