Biology subjects

Silva, C. J.

Publications and source records attributed to Silva, C. J..

3 recordsLinked to original sources

bioRxiv2020

Synchronization and interaction of proline, ascorbate and oxidative stress pathways under abiotic stress combination in tomato plants

ABSTRACTAdverse environmental conditions have a devastating impact on plant productivity. In nature, multiple abiotic stresses occur simultaneously, and plants have evolved unique responses to cope against this combination of stresses. Here, we coupled genome-wide transcriptional profiling and untargeted metabolomics with physiological and biochemical analyses to characterize the effect of salinity and heat applied in combination on the metabolism of tomato plants. Our results demonstrate that this combination of stresses causes a unique reprogramming of metabolic pathways, including changes in the expression of 1,388 genes and the accumulation of 568 molecular features. Pathway enrichment analysis of transcript and metabolite data indicated that the proline and ascorbate pathways act synchronously to maintain cellular redox homeostasis, which was supported by measurements of enzymatic activity and oxidative stress markers. We also identified key transcription factors from the basic Leucine Zipper Domain (bZIP), Zinc Finger Cysteine-2/Histidine-2 (C2H2) and Trihelix families that are likely regulators of the identified up-regulated genes under salinity+heat combination. Our results expand the current understanding of how plants acclimate to environmental stresses in combination and unveils the synergy between key cellular metabolic pathways for effective ROS detoxification. Our study opens the door to elucidating the different signaling mechanisms for stress tolerance.HIGHLIGHTSThe combination of salinity and heat causes a unique reprogramming of tomato metabolic pathways by changing the expression of specific genes and metabolic features.Proline and ascorbate pathways act synchronously to maintain cellular redox homeostasisKey transcription factors from the basic Leucine Zipper Domain (bZIP), Zinc Finger Cysteine-2/Histidine-2 (C2H2) and Trihelix families were identified as putative regulators of the identified up-regulated genes under salinity and heat combination.View Full Text

plant biology↗

bioRxiv2020

Tomato fruit susceptibility to fungal disease can be uncoupled from ripening by suppressing susceptibility factors

The increased susceptibility of ripe fruit to fungal pathogens poses a substantial threat to crop production and marketability. Here, we coupled transcriptomic analyses with mutant studies to uncover critical processes associated with defenses and susceptibility in tomato (Solanum lycopersicum) fruit. Using unripe and ripe fruit inoculated with three fungal pathogens, we identified common pathogen responses reliant on chitinases, WRKY transcription factors, and reactive oxygen species detoxification. We established that the magnitude and diversity of defense responses do not significantly impact the interaction outcome, as susceptible ripe fruit mounted a strong defense response to pathogen infection. Then, to distinguish features of ripening that may be responsible for susceptibility, we utilized non-ripening tomato mutants that displayed different susceptibility patterns to fungal infection. Based on transcriptional and hormone profiling, susceptible tomato genotypes had losses in the maintenance of cellular redox homeostasis, while jasmonic acid accumulation and signaling coincided with defense activation in resistant fruit. We identified and validated a susceptibility factor, pectate lyase (PL). CRISPR-based knockouts of PL, but not polygalacturonase (PG2a), reduced susceptibility of ripe fruit by >50%. This study suggests that targeting specific genes that drive susceptibility is a viable strategy to improve the resistance of tomato fruit against fungal disease. HighlightIncreased susceptibility to fungal disease during tomato ripening is driven by the accumulation of susceptibility factors and not the lack of defense responses.

plant biology↗

bioRxiv2017

Firefly genomes illuminate the origin and evolution of bioluminescence

Fireflies are among the best-studied of the bioluminescent organisms. Despite longterm interest in the biochemistry, neurobiology, and evolution of firefly flash signals and the widespread biotechnological applications of firefly luciferase, only a limited set of genes related to this complex trait have been described. To investigate the genetic basis of firefly bioluminescence, we generated a high-quality reference genome for the Big Dipper firefly Photinus pyralis, from which the first laboratory luciferase was cloned, using long-read (PacBio), short-read (Illumina), and Hi-C sequencing technologies. To facilitate comparative genomics, we also generated short-read genome assemblies for a Japanese firefly Aquatica lateralis and a bioluminescent click beetle, Ignelater luminosus. Analyses of these genomic datasets supports at least two independent gains of luminescence in beetles, and provides new insights into the evolution of beetle bioluminescence and chemical defenses that likely co-evolved over their 100 million years of evolution.

genomics↗