Biology subjects

Glowacka, K.

Publications and source records attributed to Glowacka, K..

3 recordsLinked to original sources

bioRxiv2023

Genotype-specific nonphotochemical quenching responses to nitrogen deficit are linked to chlorophyll a to b ratios

Non-photochemical quenching (NPQ) protects plants from photodamage caused by excess light energy. The mechanism of NPQ appears to be conserved across flowering plants. However, substantial variation in NPQ has been reported within different genotypes of the same species grown under the environmental conditions. Individual maize genotypes from a diversity panel exhibited a range of responses to low nitrogen with some genotypes exhibiting increased NPQ between control and low nitrogen conditions and others exhibiting no change. These patterns were consistent for the same genotypes across multiple field seasons. NPQ increases under low nitrogen were correlated with shifts in the ratio of chlorophyll a to chlorophyll b consistent with a decrease in reaction centers. Both photosynthetic capacity and dry biomass accumulation decreased more in maize genotypes which were unable to maintain constant NPQ levels between control and low N conditions. Collectively these results suggest that the ability to maintain sufficient numbers of reaction centers under low nitrogen conditions and avoid dissipating a greater proportion of absorbed light energy via the NPQ pathway may play a key role in increasing carbon fixation and productivity in nitrogen-limited environments. HighlightsO_LISubstantial variation in NPQ kinetics exists in maize on both low and control N. C_LIO_LIIn early and late-vegetative stages a similar portion of genotypes increased, no-change or decreased NPQmax in response to low N while in the post-flowering stage substantially more genotypes decreased NPQmax. C_LIO_LIIn low nitrogen conditions, the NPQmax strongly correlates with shifts in Chl a/Chl b ratios. C_LI

plant biology↗

bioRxiv2023

Comparative GWAS identifies a role for Mendel green pea gene in the nonphotochemical quenching kinetics of sorghum, maize, and arabidopsis

Photosynthetic organisms must cope with rapid fluctuations in light intensity. Nonphotochemical quenching (NPQ) enables the dissipation of excess light energy as heat under high light conditions, whereas its relaxation under low light maximizes photosynthetic productivity. We quantified variation in NPQ kinetics across a large sorghum (Sorghum bicolor) association panel in four environments, uncovering significant genetic control for NPQ. A genome-wide association study (GWAS) identified 20 unique regions in the sorghum genome associated with NPQ. We detected strong signals from the sorghum ortholog of Arabidopsis thaliana SUPPRESSOR OF VARIEGATION3 (SVR3) involved in plastid-nucleus signaling and tolerance to cold. By integrating GWAS results for NPQ across maize (Zea mays) and sorghum association panels, we identified a second gene, NON-YELLOWING 1 (NYE1), originally identified by Gregor Mendel in pea (Pisum sativum) and involved in the degradation of photosynthetic pigments in light-harvesting complexes, along with OUTER ENVELOPE PROTEIN 37 (OEP37), that encodes a transporter in chloroplast envelope. Analysis of nye1 insertion alleles in A. thaliana confirmed the effect of this gene on NPQ kinetics across monocots and eudicots. We extended our comparative genomics GWAS framework across the entire maize and sorghum genomes, identifying four additional loci involved in NPQ kinetics. These results provide a baseline for engineering crops with improved NPQ kinetics and increasing the accuracy and speed of candidate gene identification for GWAS in species with high linkage disequilibrium.

plant biology↗

bioRxiv2022

The genomics and physiology of abiotic stressors associated with global elevation gradients in Arabidopsis thaliana

Phenotypic and genetic diversity in Arabidopsis thaliana may be associated with adaptation along its wide elevational range. We took a multi-regional view of elevational adaptation and in a diverse panel of ecotypes measured plant responses to high elevation stressors: low partial CO2 pressure, high light, and night freezing. We conducted genome-wide association studies (GWAS) and found evidence of contrasting locally adaptive clines between regions. Western Mediterranean ecotypes showed low {delta}13C/early flowering at low elevations to high {delta}13C/late flowering at high elevations, while Asian ecotypes showed the opposite pattern. We mapped different candidate genes for each region, and trait-associated SNPs often showed elevational clines likely maintained by selection. Antioxidants and pigmentation showed regional differentiation but rarely elevational clines. GWAS for antioxidants identified an ascorbate transporter PHT4;4 (AT4G00370), which we show alters non-photochemical quenching kinetics under high light and may be involved in local adaptation to Moroccan mountains. The low-antioxidant PHT4;4 GWAS allele was associated with lower PHT4;4 expression and this haplotype was characterized by binding sites of a transcription factor family, DOF, involved in light response. Our results highlight how physiological and genomic elevational clines in different regions can be unique, underlining the complexity of local adaptation in widely distributed species.

evolutionary biology↗