Biology subjects

Weinig, C.

Publications and source records attributed to Weinig, C..

8 recordsLinked to original sources

bioRxiv2024

Reduced leaf numbers due to shade avoidance allows sugar beet to maintain biomass under drought stress

The physical environment is complex even in managed agroecosystems, and plants often experience multiple stressors such as light competition and drought simultaneously. Phenotypic responses to multiple stressors may exhibit tradeoffs or constraints, such that harvestable yield is reduced In this study, we investigate how sugar beets respond to combinations of neighbor presence, resource competition, and water stress, and test the hypothesis that shade avoidance cues from neighboring vegetation may cause yield loss similar to, or even greater than, resource depletion by neighboring vegetation. Sugar beets were grown in 19L pails surrounded by Kentucky bluegrass (Poa pratiensis). Competition treatments included "shade avoidance only" where B. vulgaris leaves were exposed to reflected light from neighbors without shading or root competition, "shade avoidance plus root interaction" where crop and competitor roots interacted, and "no competition" as a control. Sugar beets in each competition treatment were subjected to 3 levels of irrigation: 100% of estimated evapotranspiration (ET), 80% ET and 60% ET. When grown without drought stress (100% ET), the shade avoidance treatment had 16% less root biomass compared to the no competition control (P = 0.007); however, under the most severe drought treatment (60% ET) root biomass was similar between the shade avoidance and no competition treatments (P = 0.48). Under 60% ET, plants in the shade avoidance only treatment produced 15% fewer leaves (P < 0.001) but 14% greater leaf area (P = 0.049) compared to the no competition control. The reduced number of leaves produced due to shade avoidance resulted in less structural tissue to be maintained under drought stress, and thus provides a potential benefit to shade avoidance responses that are not directly related to avoiding shade.

plant biology↗

bioRxiv2024

Natural variation in circadian period correlates with diverse phenological measures in Boechera stricta

The circadian clock is a time-keeping mechanism that enables adaptive responses to temporal environmental changes. Circadian period exhibits significant segregating genetic variation within and among populations along an elevational cline, potentially resulting from variable selection across microsites on outputs of the circadian clock. Reproductive timing is an important clock output and selection may favor delayed phenology. We performed a three-year common garden field study with the short-lived perennial Boechera stricta to quantify life history differences among 20 populations from an elevational gradient and among 20 maternal families within one population. We measured days to bolting and later life history transitions such as days to flowering; in the same genotypes, we measured circadian period. The timing of all life history transitions varied among growing seasons, suggesting adaptive life history evolution to local climate conditions. Life history transitions after bolting were also associated with circadian period, such that lengthened period was associated with delayed life history transitions. Structural equation modeling indicated that indirect selection via days to flowering and fruit production favored lengthened clock period in the low elevation common garden site, suggesting that selection on phenology could explain the evolution of variable circadian periods observed among populations from differing environments.

plant biology↗

bioRxiv2019

Whole-genome duplication and host genotype affect rhizosphere microbial communities in Arabidopsis thaliana

The composition of complex microbial communities found in association with plants is influenced in part by host phenotype. Yet, the salient genetic architecture is often unknown. Genome duplication events are common in the evolutionary history of plants, influence many important plant traits, and may affect associated microbial communities. Using experimentally induced whole genome duplication (WGD), we tested the effect of WGD on rhizosphere bacterial communities in Arabidopsis thaliana. Specifically, we performed 16S rRNA amplicon sequencing to characterize differences between microbiomes associated with specific host genotypes (Columbia vs. Landsberg) and ploidy levels (diploid vs. tetraploid). We modeled abundances of individual bacterial taxa by utilizing a hierarchical Bayesian framework, based on the Dirichlet and multinomial distributions. We found that host genotype and host ploidy level affected rhizosphere community composition, for instance, the microbiome of the tetraploid Columbia genotype differed from that of other host genotypes. We then tested to what extent microbiomes derived from a given host genotype or ploidy level affected plant performance by inoculating sterile seedlings of each genotype with microbial communities harvested from a prior generation. We found a negative effect of the tetraploid Columbia microbiome on growth of all four plant genotypes. The findings suggest that while both host genotype and ploidy affect microbial community assembly, bacterial communities found in association with only some host genotypes may affect growth of subsequent plant generations. ImportancePlants influence the composition of their associated microbial communities; yet the underlying host genetic factors are often unknown. Genome duplication events are common in the evolutionary history of plants and affect many plant traits, including the quality and quantity of compounds exuded into the root zone, which can affect root-bound microbes. In Arabidopsis thaliana, we characterized how whole-genome duplication affected the composition of rhizosphere bacterial communities, and how bacterial communities associated with two host plant genotypes and ploidy levels affected subsequent plant growth. We observed an interaction in which ploidy level within one host genotype affected both bacterial community composition and function. This research reveals how genome duplication, a widespread genetic feature of both wild and crop plant species, influences the coexistence of bacterial taxa and affects plant growth.

plant biology↗

bioRxiv2019

Integrating transcriptomic network reconstruction and QTL analyses reveals mechanistic connections between genomic architecture and Brassica rapa development

Plant developmental dynamics can be heritable, genetically correlated with fitness and yield, and undergo selection. Therefore, characterizing the mechanistic connections between the genetic architecture governing plant development and the resulting ontogenetic dynamics of plants in field settings is critically important for agricultural production and evolutionary ecology. We use a hierarchical Bayesian Function-Valued Trait (FVT) approach to estimate Brassica rapa growth curves throughout ontogeny, across two treatments and in two growing seasons. We find that the shape of growth curves is relatively plastic across environments compared to final height, and that there are trade-offs between growth rate and duration. We determined that combining FVT Quantitative Trait Loci (QTL) and genes/eigengene expression identified via transcriptomic co-expression network reconstructions best characterized phenotypic variation. Further, targeted eQTL analyses identified regulatory hotspots that colocalized with FVT QTL and co-expression network identified genes and mechanistically link FVT QTL with structural trait variation throughout development in agroecologically relevant field settings.

genomics↗

bioRxiv2018

A framework for genomics-informed ecophysiological modeling in plants

Dynamic process-based plant models capture complex physiological response across time, carrying the potential to extend simulations out to novel environments and lend mechanistic insight to observed phenotypes. Despite the translational opportunities for varietal crop improvement that could be unlocked by linking natural genetic variation to first-principles based modeling, these models are challenging to apply to large populations of related individuals. Here we use a combination of model development, experimental evaluation, and genomic prediction in Brassica rapa L. to set the stage for future large-scale process-based modeling of intra-specific variation. We develop a new canopy growth sub-model for B. rapa within the process-based model Terrestrial Regional Ecosystem Exchange Simulator (TREES), test input parameters for feasibility of direct estimation with observed phenotypes across cultivated morphotypes and indirect estimation using genomic prediction on a Recombinant Inbred Line population, and explore model performance on an in silico population under non-stressed and mild water stressed conditions. We find evidence that the updated whole plant model has capacity to distill genotype by environment interaction (G x E) into tractable components. The framework presented offers a means to link genetic variation with environment-modulated plant response and serves as a stepping stone towards large-scale prediction of un-phenotyped, genetically-related individuals under un-tested environmental scenarios.

plant biology↗

bioRxiv2018

Rhizosphere microbes influence host circadian clock function

The circadian clock is an important determinant of individual fitness that is entrained by local conditions. In addition to known abiotic inputs that entrain the circadian clock, individual pathogenic soil bacteria affect the circadian period of plant hosts. Yet, in nature, plants interact with diverse microbial communities including hundreds to thousands of microbial taxa, and the effect of these communities on clock function remains unclear. In Arabidopsis thaliana, we used diverse rhizosphere inoculates and both wild-type and clock mutant genotypes to test the effect of complex rhizosphere microbial communities on the host circadian clock. Host plants with an intact rhizosphere microbiome expressed a circadian period that was closer to 24 hrs in duration and significantly shorter (by 60 minutes on average) relative to plants grown with a disrupted microbiome. Wild-type host genotypes differed significantly in clock sensitivity to microbiome treatments, where the effect was most pronounced in the Landsberg erecta genotype and least in the Columbia genotype. Rhizosphere microbes collected from a host genotype with a short-period phenotype (toc1-21) and used as inoculate significantly shortened the long-period phenotype of the ztl-1 clock mutant genotype. The results indicate that complex rhizosphere microbial communities significantly affect host clock function.

plant biology↗

bioRxiv2018

Rhizosphere microbes and host plant genotype influence the plant metabolome and reduce insect herbivory

O_LIRhizosphere microbes affect plant performance, including plant resistance against insect herbivores; yet, the relative influence of rhizosphere microbes vs. plant genotype on herbivory levels and on metabolites related to defense remains unclear.\nC_LIO_LIIn Boechera stricta, we tested the effects of rhizosphere microbes and plant genotype on herbivore resistance, the primary metabolome, and select secondary metabolites.\nC_LIO_LIPlant populations differed significantly in the concentrations of 6 glucosinolates (GLS), secondary metabolites known to provide herbivore resistance in the Brassicaceae, and the population with lower GLS levels experienced ~60% higher levels of aphid (Aphis spp.) attack; no effect was observed of GLS on damage by a second herbivore, flea beetles (Altica spp.). Rhizosphere microbiome (intact vs. disrupted) had no effect on plant GLS concentrations. However, aphid number and flea beetle damage were respectively ~3-fold and 7-fold higher among plants grown in the disrupted rhizosphere microbiome treatment, and distinct (as estimated from 16s rRNA amplicon sequencing) intact native microbiomes also differed in their effects on herbivore damage. These differences may be attributable to shifts in primary metabolic pathways.\nC_LIO_LIThe findings suggest that rhizosphere microbes can play a greater role than plant genotype in defense against insect herbivores, and act through mechanisms independent of plant genotype.\nC_LI

plant biology↗

bioRxiv2017

The plant circadian clock influences rhizosphere community structure and function

Plants alter chemical and physical properties of soil, and thereby influence rhizosphere microbial community structure. The structure of microbial communities may in turn affect plant performance. Yet, outside of simple systems with pairwise interacting partners, the plant genetic pathways that influence microbial community structure remain largely unknown, as are the performance feedbacks of microbial communities selected by the host plant genotype. We investigated the role of the plant circadian clock in shaping rhizosphere community structure and function. We performed 16S rRNA gene sequencing to characterize rhizosphere bacterial communities of Arabidopsis thaliana between day and night time points, and tested for differences in community structure between wild-type (Ws) vs. clock mutant (toc1-21, ztl-30) genotypes. We then characterized microbial community function, by growing wild-type plants in soils with an overstory history of Ws, toc1-21 or ztl-30 and measuring plant performance. We observed that rhizosphere community structure varied between day and night time points, and clock misfunction significantly altered rhizosphere communities. Finally, wild-type plants germinated earlier and were larger when inoculated with soils having an overstory history of wild-type in comparison to clock mutant genotypes. Our findings suggest the circadian clock of the plant host influences rhizosphere community structure and function.

plant biology↗