Biology subjects

Olmedo, G.

Publications and source records attributed to Olmedo, G..

3 recordsLinked to original sources

bioRxiv2023

A large sensory and multi-omics evaluation unraveled chemical and genetic basis of orange flavor

Sweet orange (Citrus sinensis) exhibits limited genetic diversity and high susceptibility to Huanglongbing (HLB). New HLB-tolerant orange-like hybrids are promising alternatives. However, the genetic control of key flavor compounds in oranges remains unknown. Evaluating 179 juice samples, including oranges, mandarins, Poncirus trifoliata and hybrids, distinct volatile compositions were found. A random forest model predicted untrained samples with 78% accuracy and identified 26 compounds crucial for orange flavor. Notably, seven esters--methyl hexanoate, ethyl hexanoate, ethyl 3-hydroxyhexanoate, ethyl octanoate, methyl butanoate, ethyl butanoate, and ethyl 2-methylbutanoate--differentiated orange from mandarin. Cluster analysis showed six esters with shared genetic control. Differential gene expression analysis identified CsAAT1, an alcohol acyltransferase responsible for ester production in orange. Its activity was validated through overexpression assays. A SNP-based DNA marker in the CDS region accurately predicted phenotypes. This study enhances our understanding of orange flavor compounds, their biosynthetic pathways, and expands breeding options for orange-like cultivars.

genetics↗

bioRxiv2019

Diversity of Archaea Domain in Cuatro Cienegas Basin: Archaean Domes.

Herein we describe the Archaea diversity in a shallow pond in the Cuatro Cienegas Basin (CCB), Northeast Mexico, with fluctuating hypersaline conditions containing elastic microbial mats that can form small domes where their anoxic inside reminds us of the characteristics of the Archaean Eon, rich in methane and sulfur gases; thus, we named this site the Archaean Domes (AD). These domes only form after heavy rains that are rare in the Chihuahuan desert. CCB is a unique oasis with hundreds of ponds, containing endemic species of animals, plants and highly diverse and unique microbial communities, despite its very biased stoichiometry, due mostly to extreme low phosphorus content (soils, water columns and sediments). This extreme oligotrophy has favored survival of ancestral microorganisms. Whole metagenome sequencing approach was performed for this unusual site in three different seasons to assess the extent of the Archaea biodiversity, with a focus on extremophiles, since members of the Archaea had been underrepresented in different study sites within the oasis. We found a highly diverse Archaea community compassing [~]5% of the metagenomes. The archaeal portion in all three metagenomes maintained its abundance and most of the strains showed to form a resilient core during three seasonal samplings (2016-2017), despite environmental fluctuations. However, relative abundances of all 230 archaeal OTUs (defined using a 97% cutoff) were low enough (<0.1%) to be considered part of the rare biosphere. AD finding and their description within CCB confirms that this particular pond is the most diverse for Archaea that we are aware of and opens new paths for understanding the forces that once drove and keep shaping microbial community assemblage.

microbiology↗

bioRxiv2018

The lost world of Cuatro Cienegas Basin, a relictual bacterial niche in a desert oasis.

Barriers to immigration can lead to localized adaptive radiations and increased endemism. We propose that extreme oligotrophy can be a strong barrier to immigration over geological timescales, and facilitate the evolution of diverse and coevolved microbial communities. We show here that the endangered oasis of Cuatro Cienegas Basin can be a model for a lost world, where the ancient niche of extreme oligotrophy favoured survival of ancestral microorganisms that persisted due to environmental stability and low extinction rates, generating a diverse and unique bacteria diversity. Diversification/extinction rates in Bacillus showed several CCB endemic clades that diverged from the rest of Bacillus spp. in different times of the Paleozoic and Mesozoic, in contrast to more recent Bacillus, Clostridium and Bacteroidetes lineages. CCB conservation is vital to the understanding of early evolutionary and ecological processes.

evolutionary biology↗