Biology subjects

Cauz-Santos, L. A.

Publications and source records attributed to Cauz-Santos, L. A..

6 recordsLinked to original sources

bioRxiv2025

Puzzling parasitic plants: phylogenetics and classification of Santalales revisited

Based on a previously published but realigned matrix for Santalales, we find many relationships that were weakly or unsupported in previous studies are here much better supported, providing a more robust foundation upon which to discuss Santalales classification. In the maximum likelihood analysis, we recovered the same basic relationships as in the previous studies, but with two major differences: i) Balanophoraceae in the broad sense are monophyletic and well supported as embedded in Santalaceae (rather than biphyletic and outside Santalaceae) and ii) most of the former Olacaceae form a moderately supported clade (rather than a weakly supported grade). In the parsimony analysis, the position of Balanophoraceae s.l. is not well supported (although their broader circumscription is). We outline three possible options for a classification of the order and propose a new familial and subfamilial classification for Santalales. This hopefully provides a stable, user- friendly taxonomic framework that is phylogenetically well supported and more consistent with historical usage than some recently proposed systems, and provides taxa that can be more readily diagnosed morphologically. We recommend recognition of nine families (in phylogenetic sequence): Strombosiaceae, Erythropalaceae, Olacaceae, Opiliaceae, Santalaceae, Misodendraceae, Schoepfiaceae and Loranthaceae, plus an unresolved position for Balanophoraceae (including Mystropetalaceae), which we propose to exclude from Santalaceae until more evidence of their relationships to that family is available from nuclear genes. Four new subfamilies, Gaiadendroideae, Comandroideae, Nanodeoideae and Thesioideae, are proposed, and a new combination, Loranthus obtusifolius, is made.

evolutionary biology↗

bioRxiv2024

Recent speciation and adaptation to aridity in the ecologically diverse Pilbara region of Australia enabled the native tobaccos (Nicotiana; Solanaceae) to colonize all Australian deserts

For the last six million years, the arid Australian Eremaean Zone (EZ) has been as dry as today. An accepted hypothesis, applied to arid regions worldwide, suggests that flora and fauna were more broadly distributed before aridification began. In Australia, this aridification process started around 20 million years ago (Mya), leading to gradual speciation processes via vicariance as the climate became increasingly arid. Here, we use genomic data to investigate the biogeography and timing of divergence of native allotetraploid tobaccos, Nicotiana section Suaveolentes (Solanaceae), which putatively entered the EZ 5 Mya. The original allotetraploid migrants from South America were adapted to mesic areas of Australia and putatively radiated recently in the EZ, including sandy dune fields (only 1.2 My old), after developing drought adaptations. Based on coalescent and maximum likelihood analyses designed to corroborate timing of the Australian radiation independently, arrival of Nicotiana section Suaveolentes on the continent occurred approximately 6 Mya, and ancestors of the Pilbara (Western Australian) lineages radiated there at the onset of extreme aridity 5 Mya by locally adapting to these various ancient, highly stable habitats. The Pilbara thus served as both a mesic refugium and cradle for adaptations to harsher conditions. This dual role is due to its high topographical diversity, providing microhabitats with varying moisture levels, and its proximity to the ocean, which buffers against extreme aridity. Consequently, species like Nicotiana have been able to survive in mesic refugia during arid periods and subsequently adapt to more arid conditions. These results demonstrate that initially poorly adapted plant groups can develop novel adaptations in situ, permitting extensive and rapid wide dispersal despite the highly variable and unpredictable extremes of heat and drought in the EZ.

evolutionary biology↗

bioRxiv2023

Short structural variation fuelled CAM evolution within an explosive bromeliad radiation

1.The subgenus Tillandsia (Bromeliaceae) belongs to one of the fastest radiating clades in the plant kingdom and is characterised by the repeated evolution of Crassulacean Acid Metabolism (CAM). Despite its complex genetic basis, this water-conserving trait has evolved independently across many plant families and is regarded as a key innovation trait and driver of ecological diversification in Bromeliaceae. By producing high-quality genome assemblies of a Tillandsia species pair displaying divergent photosynthetic phenotypes, and combining genome-wide investigations of synteny, TE dynamics, sequence evolution, gene family evolution and temporal differential expression, we were able to pinpoint the genomic drivers of CAM evolution in Tillandsia. Several large-scale rearrangements associated with karyotype changes between the two genomes and a highly dynamic TE landscape shaped the genomes of Tillandsia. However, our analyses show that rewiring of photosynthetic metabolism is mainly obtained through regulatory evolution rather than coding sequence evolution, as CAM-related genes are differentially expressed across a 24-hour cycle between the two species, but are no candidates of positive selection. Gene orthology analyses reveal that CAM-related gene families manifesting differential expression underwent accelerated gene family expansion in the constitutive CAM species, further supporting the view of gene family evolution as a driver of CAM evolution.

evolutionary biology↗

bioRxiv2022

Variation of the Rdr1 gene insertion in wild populations of Nicotiana benthamiana (Solanaceae) and insights into recent species divergence

O_LIOne of the most commonly encountered and frequently cited laboratory organisms worldwide is classified taxonomically as Nicotiana benthamiana (Solanaceae), an accession of which, typically referred to as LAB, is renowned for its unique susceptibility to a wide range of plant viruses and hence capacity to be transformed using a variety of methods. However, the origin and age of LAB and the evolution of N. benthamiana across its wide distribution in Australia remains relatively underexplored. C_LIO_LIHere, we have used multispecies coalescent methods on genome-wide single nuclear polymorphisms (SNPs) to assess species limits, phylogenetic relationships and divergence times within N. benthamiana. C_LIO_LIOur results show that the previous taxonomic concept of this species in fact comprises five geographically, morphologically and genetically distinct species, one of which includes LAB. C_LIO_LIRemarkably, we provide clear evidence that LAB is closely related to accessions collected further north in the Northern Territory; this species split much earlier from their common ancestor than the other four in this clade and is morphologically the most distinctive. Furthermore, this long-isolated species typically grows in sheltered sites in subtropical/tropical monsoon areas of northern Australia, contradicting the previously advanced hypothesis that this species is an extremophile that has traded viral resistance for precocious development. C_LI

evolutionary biology↗

bioRxiv2020

Large vs small genomes in Passiflora: the influence of the mobilome and the satellitome

Repetitive sequences are ubiquitous and fast-evolving elements responsible for size variation and large-scale organization of plant genomes. Within Passiflora genus, a ten-fold variation in genome size, not attributed to polyploidy, is known. Here, we applied a combined in silico and cytological approach to study the organization and diversification of repetitive elements in three species of these genera representing its known range in genome size variation. Sequences were classified in terms of type and repetitiveness and the most abundant were mapped to chromosomes. We identified Long Terminal Repeat (LTR) retrotransposons as the most abundant elements in the three genomes, showing a considerable variation among species. Satellite DNAs (satDNAs) were less representative, but highly diverse between subgenera. Our results clearly confirm that the largest genome species (Passiflora quadrangularis) presents a higher accumulation of repetitive DNA sequences, specially Angela and Tekay elements, making up most of its genome. Passiflora cincinnata, with intermediate genome and from the same subgenus, showed similarity with P. quadrangularis regarding the families of repetitive DNA sequences, but in different proportions. On the other hand, Passiflora organensis, the smallest genome, from a different subgenus, presented greater diversity and the highest proportion of satDNA. Altogether, our data indicate that while large genome evolve by an accumulation of retrotransponsons, small genomes most evolved by diversification of different repeat types, particularly satDNAs. MAIN CONCLUSIONSWhile two lineages of retrotransposons were more abundant in larger Passiflora genomes, the satellitome was more diverse and abundant in the smallest genome.

evolutionary biology↗

bioRxiv2019

Improving yield and fruit quality traits in sweet passion fruit: evidence for genotype by environment interaction and cross-compatibility in selected genotypes

Breeding for yield and fruit quality traits in passion fruits is complex due to the polygenic nature of these traits and the existence of genetic correlations among them. Therefore, studies focused on crop management practices and breeding using modern quantitative genetic approaches are still needed, especially for Passiflora alata, an understudied crop, popular known as the sweet passion fruit. It is assumed to be a self-incompatible species and is highly appreciated for its typical aroma and flavor characteristics. With the aim of estimating the genetic and phenotypic parameters related to fruit traits, our group has already investigated a sweet passion fruit progeny consisting of 100 individuals from which 30 genotypes were selected. In this study, we reevaluated these superior genotypes in three environmental conditions. The results of the multi-environment trial analysis indicate that the genotypes do not behave consistently across these environments, and this was taken into account when selecting genotypes. Pairwise genetic correlations among the fruit traits were evaluated, and different genotype rankings obtained depending on the trait and environment, providing further evidence of genotype by environment interaction. Finally, we used a multiplicative selection index to select 20% of genotypes for weight of pulp and against thickness and weight of the fruit skin. The response to selection was positive for all traits except soluble solids, and the superior (six) genotypes were ranked. The consensus is that open-pollinated populations can be used as commercial varieties in crop species that are sensitive to inbreeding depression or within breeding programs that are not well developed. For these reasons, we performed a complete diallel cross for evaluating the capability of the selected genotypes to be fertilized and set fruits. Most of the crosses were compatible, resulting in over 50% fruit set. It is worth noting that all genotypes produce fruits if used as females, which is essential to guarantee yields in commercial orchards.

plant biology↗