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Biology subjects

de Bernardeaux, G.

Publications and source records attributed to de Bernardeaux, G..

3 recordsLinked to original sources

A simple and efficient CTAB plate-based protocol for genomic DNA extraction from crop plants

Modern plant breeding and molecular genetics rely on genotyping large populations for applications such as genome editing and genomic selection. However, current DNA extraction methods often require expensive equipment or signif-icant manual labor, which limits their scalability. The objective of this study was to develop a scalable, cost-effective DNA extraction method. A bead-beating protocol was used to homogenize small amounts of leaf tissue from Arabidopsis, camelina, maize, sorghum, soybean, tobacco, and wheat, as well as developing soybean seeds. Samples were processed in 96-well plates using a standard CTAB (cetyltrimethylammonium bromide)-based extraction solution. DNA concentration was measured, and DNA quality was estimated using the A260/A280 and A260/A230 ratios and gel electrophoresis. The extracted DNA was then used for PCR assays to amplify targeted endogenous sequences, detect Cas9-edited sequences, and estimate gene copy numbers. This workflow enabled a single worker to process up to 960 samples per day. The total DNA yield was 2-3 {micro}g for leaf and 0.5-1 {micro}g for soybean seeds with good quality, which was sufficient for multiple PCR reactions. The DNA was successfully used for the intended PCR assays. The extracted DNA was suitable for reliable, downstream PCR-based genotyping. This method supports diverse analyses, including routine amplification, identification of genome edits, and copy number analysis.

plant biology↗

Nonphotochemical quenching changes with abiotic stressor and developmental stages

Nonphotochemical quenching (NPQ) is a critical photoprotective mechanism in plants, safeguarding photosystem II (PSII) and PSI from photodamage under abiotic stress. However, it is unclear if different stressors lead to similar NPQ phenotypes, and the magnitude of natural variation (between and within plant species) in NPQ response to abiotic stress is unknown. Testing a semi-high-throughput leaf-disc approach for examining the NPQ kinetics parameters, we investigated NPQ under chilling, drought and low nitrogen stress across multiple species and/or genotypes. Our results show substantial variation in NPQ phenotypes across species, genotypes and treatments. In C3 crops, tobacco and soybean, multiple NPQ parameters generally increased under chilling and drought, while in C4 crops, maize and sorghum, NPQ traits were more variable including a decrease of multiple NPQ parameters. Low-N stress revealed genotype- and developmental stage-specific effects on NPQ, potentially reflecting distinct adaptive strategies and regulatory changes in NPQ stress response. A significant effect of ecotype and stress treatment was detected on most NPQ kinetics traits in Arabidopsis thaliana, however, the interaction between ecotype and treatment was stronger in drought than in chilling. Differential regulation of NPQ could be associated with a combination of changes in proton motive, ATPase synthase activity, and PSI redox state. Our findings highlight that interpreting relative changes in NPQ under abiotic stress is inherently complex and demands a broader integration of physiological data across multiple regulatory layers.

physiology↗

Quantitative genetics of photosynthetic trait variation in maize

Natural genetic variation in photosynthesis-related traits can aid both in identifying genes involved in regulating photosynthetic processes and developing crops with improved productivity and photosynthetic efficiency. However, rapidly fluctuating environmental parameters create challenges for measuring photosynthetic parameters in large populations under field conditions. We measured chlorophyll fluorescence and absorbance-based photosynthetic traits in a maize diversity panel in the field using an experimental design that allowed us to estimate and control multiple confounding factors. Controlling the impact of day of measurement and light intensity as well as patterns of two-dimensional spatial variation in the field substantially increased heritability with the heritability of 7 out of 14 traits measured exceeding 0.4. We were able to identify high confidence GWAS signals associated with variation in four spatially corrected traits (the quantum yield of photosystem II, non-photochemical quenching, redox state of QA, and relative chlorophyll content). Insertion alleles for Arabidopsis orthologs of three candidate genes exhibited phenotypes consistent with our GWAS results. Collectively these results illustrate the potential of applying best practices from quantitative genetics research to address outstanding questions in plant physiology and understand the mechanisms underlying natural variation in photosynthesis. Highlights[bullet] Controlling spatial and environmental confounding factors increased heritability of photosynthetic traits. [bullet]GWAS identified high confidence signals associated with variation in relative chlorophyll, {Phi}PSII, {Phi}NPQ, and qL. [bullet]Insertion alleles of the Arabidopsis orthologs of maize candidate genes exhibited photosynthesis related phenotypes consistent with the GWAS results.

plant biology↗