Biology subjects

Serra, O.

Publications and source records attributed to Serra, O..

4 recordsLinked to original sources

bioRxiv2025

Advances on the bacterial diversity and functionality of Platypus cylindrus - Quercus suber interaction

The ambrosia beetle Platypus cylindrus Fab. (Coleoptera: Curculionidae: Platypodinae) has been associated in Portugal with cork oak (Quercus suber) tree death since the 1980s. Although traditionally known as a secondary pest damaging stressed and dead trees, its aggressiveness changed over the last decades. Ambrosia beetle is an insect known for its interactions with several species of fungi aiming for the gain of biologic functions that facilitates its life cycle. How bacterial communities harbored by ambrosia beetle impact forest ecosystems is not yet well known. In oak species, some pathogenic bacteria are often associated with wood insect infestations. From P. cylindrus body and wood tree bored galleries, culture dependent methods led to the isolation of bacteria involved in wood degradation and beetle ecology and even a new bacterial cork oak pathogen. To complement colony isolation efforts for the identification of the beetle-cork oak associated bacterial community, the same samples were analyzed with 16S metabarcoding. Two distinct bacterial communities from beetle mycangia and wood galleries sharing the most abundant bacterial taxa were revealed. A group of genera from Enterobacterales and Bradyrhizobium prevailed in the samples from wood galleries. Comparison between ASVs and full 16S sequences allowed the identification of Pectobacteriaceae as the major taxon from unclassified Enterobacterales carried by the beetle. Prediction of metabolic pathways varying between wood galleries and beetle mycangia revealed upregulation in the galleries of carbohydrate and virulence factors. Together, these analyses efficiently compared the bacteriome from the wood galleries with the beetle mycangia, revealing different bacterial communities and specific ecological roles related to both the beetle and trees. Additionally, they gave insights into the comparability of culture-dependent and independent methods in bacteriome analysis.

ecology↗

bioRxiv2023

A Functional Exodermal Suberin is Key for Plant Nutrition and Growth in Potato

Angiosperm roots, except in Arabidopsis, have both endodermis and exodermis, which regulate radial water and solute movement through lignin and suberin deposition. While endodermal suberin in Arabidopsis acts as a barrier to water and solute uptake and backflow, its implications in other angiosperms with both layers and the role of exodermal suberin remain unclear. We examined potato roots (Solanum tuberosum) and found that exodermis lacks the typical Casparian strip but forms an outer lignin cap, and quickly suberizes near the root tip. In contrast, a few endodermal cells, with Casparian strip, start suberizing much later. The continuous early exodermal suberization covering the root underlines its potential role in mineral nutrient radial movement. To demonstrate it, we used plants downregulating the suberin biosynthetic gene CYP86A33, which had the root suberin reduced in a 61%. Phenotypic analyses of the suberin-deficient mutant showed altered mineral nutrient concentration, slightly reduced water content and compromised growth. Micro-PIXE analyses identified the distribution of elements within the roots and highlighted anatomical compartments defined by apoplastic barriers. These findings advance our understanding of nutrient radial transport, demonstrate exodermal suberin as a bidirectional and selective barrier to element movement, and underscore its importance in nutrient homeostasis and plant growth.

plant biology↗

bioRxiv2023

Rhytidome- and cork-type barks of holm oak, cork oak and their hybrids highlight processes leading to cork formation

The periderm is basic for land plants due to its protective role during radial growth, which is achieved by the polymers deposited in the cell walls. In most trees, like holm oak, the periderm is frequently replaced by subsequent internal periderms yielding a heterogeneous outer bark made of a mixture of periderms and phloem tissues, known as rhytidome. Exceptionally, cork oak forms a persistent or long-lived periderm which results in a homogeneous outer bark of thick phellem cell layers known as cork. Here we use the outer bark of cork oak, holm oak, and their natural hybrids to analyse the chemical composition, the anatomy and the transcriptome, and further understand the mechanisms underlying periderm development. The inclusion of hybrid samples showing rhytidome-type and cork-type barks is valuable to approach to cork and rhytidome development, allowing an accurate identification of candidate genes and processes. The present study underscores that biotic stress and cell death signalling are enhanced in rhytidome-type barks whereas lipid metabolism and cell cycle are enriched in cork-type barks. Development-related DEGs, showing the highest expression, highlight cell division, cell expansion, and cell differentiation as key processes leading to cork or rhytidome-type barks.

cell biology↗

bioRxiv2021

Induced ligno-suberin vascular coating and tyramine-derived hydroxycinnamic acid amides restrict Ralstonia solanacearum colonization in resistant tomato roots

The soil borne pathogen Ralstonia solanacearum is the causing agent of bacterial wilt, a devastating disease affecting major agricultural crops. R. solanacearum enters plants through the roots and reaches the vasculature, causing rapid wilting. We recently showed that tomato varieties resistant to bacterial wilt restrict bacterial movement in the plant. In the present work we go a step forward by identifying the physico-chemical nature of the barriers induced in resistant tomato roots in response to R. solanacearum. We describe that resistant tomato specifically responds to infection by assembling de novo a structural barrier at the vasculature formed by a ligno-suberin coating and tyramine-derived hydroxycinnamic acid amides (HCAAs). On the contrary, susceptible tomato does not form these reinforcements in response to the pathogen but instead displays lignin structural changes compatible with its degradation. Further, we show that overexpressing genes of the ligno-suberin pathway in a commercial susceptible variety of tomato restricts R. solanacearum movement inside the plant and slows disease progression, enhancing resistance to the pathogen. We thus propose that the induced barrier in resistant plants does not only restrict the movement of the pathogen, but may also prevent cell wall degradation by the pathogen and confer anti-microbial properties.

plant biology↗