Plant Biology

eLife assessment:

This important study convincingly shows that the endopeptidases ECS1 and ECS2 repress the formation of polyspermy-derived triparental offspring and haploid induction by promoting double fertilization. While the underlying mechanisms remain to be further elucidated, the data presented in this study represent a valuable foundation for understanding the regulation of offspring genome size. This study will be of particular interest to the large community of scientists who are interested in plant reproduction and breeding.

eLife assessment

Secondary cell walls support vascular plants and conduct water throughout the plant body, and are crucial resources for lignocellulosic feedstocks. Here the authors present convincing genetic and biochemical evidence that secondary cell wall synthesis, known already to be under complex transcriptional control, is also controlled post-transcriptionally by MUSASHI-like RNA-binding proteins. These important results point to a new mechanism for control of secondary cell wall synthesis, which will be interesting to cell biologists and biochemists studying and attempting to manipulate plant biomass.

eLife assessment

This study presents findings that are important for understanding plant-soil feedbacks in agriculture. The authors use a large-scale agricultural field experiment to demonstrate the role of root-emitted secondary metabolites in enhancing the yield of the next crop. By using a benzoxazinoid-deficient maize genotype, the authors provide compelling evidence that biomass production and grain yield of several wheat varieties can be increased when grown in soil conditioned by maize plants able to release benzoxazinoids.

eLife assessment

This manuscript presents valuable findings on the role of a plant peptide in coordinating developmental and immune responses signaling. The evidence supporting the claims, while mainly descriptive and and somewhat limited due to the main conclusions being drawn from overexpression lines, is mostly solid. The findings are interesting, they align with existing models, and they are of relevance to plant pathologists and developmental biologists.

eLife assessment

This study presents a useful set of experiments to test how a salivary protein might facilitate planthopper-transmitted rice stripe virus infection by interfering with callose deposition. If the conclusions can be confirmed, the study will enhance our understanding of the mechanisms mediating tripartite virus-insect vector-plant interactions and would be of general interest in plant science research. Whereas most experimental data is compelling, the conclusions rely on inadequate evidence for the salivary protein carbonic anhydrase being present two weeks post injection in the plant, which seems unlikely.

eLife assessment

This study is of fundamental importance, addressing the regulation of the carbon concentrating mechanism in cyanobacteria. It is a well-controlled investigation of low affinity regulatory binding of small molecules, processes that are typically difficult to examine. The work provides compelling evidence that the adenylate pool, rather than any single metabolite, regulates a key bicarbonate transporter (SbtA) to provide efficient bicarbonate supply while preventing futile cycling that can result from escape of unfixed CO2.

eLife assessment

This is an important paper that combines methods ranging from agronomy and plant breeding to Arabidopsis functional genetics, to argue that polymorphism in a single gene affects crop yield in pearl millet by affecting root cell elongation and drought stress resilience in a poorly studied crop. The overall argument is plausible but whether the solid evidence generated with Arabidopsis experiments can be extended to pearl millet itself is unclear.

eLife assessment

This valuable study shows that new, virulent genotypes of Xanthomonas oryze pv. oryzae, that are similar to strains present in east Asia, cause outbreaks of bacterial blight of rice in Tanzania. The authors' use of CRISPR-based gene editing on multiple pathogen targets in an elite African rice variety to create lines resistant to both endemic and emerging pathogen strains in Africa makes for a compelling contribution to meet this alarming development. The work describing the new strains of the pathogen is solid but could be stronger if there were genome sequence data for all strains examined and a clearer presentation of recent disease outbreaks and their severity.

eLife assessment

This valuable study links natural variation in steroidal glycoalkaloid production to disease and insect resistance in potato species. The study design is straightforward and thorough, and the evidence supporting the main conclusions is solid. The work will be of interest to plant biologists and breeders.

eLife assessment

The fundamental work represents an important contribution to our understanding of the diversity of photosynthetic mechanisms across the branches of phototrophic life, with the first high-resolution structure (2.9 Å) of a photosynthetic complex from a primitive green alga. This is a valuable resource for understanding function and evolution of light-harvesting antennas. The evidence is convincing in suggesting that the mechanism found here is distinct from the classical antenna state transitions seen in other organisms studied thus far.

eLife assessment

This work is an attempt to establish conditions that accurately and efficiently mimic a drought response in Arabidopsis grown on defined agar-solidified media – an admirable goal as a reliable experimental system is key to conducting successful low water potential experiments and would enable high-throughput genetic screening (and GWAS) to assess the impacts of environmental perturbations on various genetic backgrounds. The authors compare transcriptome patterns of plants subjected to water limitation imposed using different experimental systems. The work is valuable in that it lays out the challenges of such an endeavor and points out shortcomings of previous attempts. However, a lack of water relations measurements, incomplete experimental design, and a lack of critical evaluation of these methods in light of previous results render the proposed new methodology inadequate.

eLife assessment

In this important article, the authors characterize ancient DNA from maize unearthed in archaeological contexts from Paredones and Huaca Prieta in the Chicama river valley of Peru, recovered by painstakingly controlled excavation. The genetic evidence is compelling, albeit from a small sample size, but the dating evidence, despite the excellent archaeological context, is inadequate. Since the age of the samples is so important for the inferences, the individual radiocarbon determinations should be subject to further scrutiny.

eLife assessment

This important paper advances the understanding, in the model plant Arabidopsis thaliana, of the molecular basis of the promotion of flowering in the spring by exposure to winter cold through a process known as vernalization. In Arabidopsis, there are two classes of long non-coding RNAs produced only when plants are in the cold, and this work provides compelling evidence that the cold-induced expression of one of these (COOLAIR) involves C-repeat binding factor proteins that bind to cognate binding elements in the COOLAIR promoter, but also that COOLAIR is not required for the vernalization-mediated promotion of flowering under standard laboratory conditions in which the vernalization response is measured.

eLife assessment

The work of Caspy and coworkers resolves the cryo-EM structures of stacked and unstacked PSII supercomplexes of Dunaliella, revealing unexpected connectivity and conformational flexibility, with intriguing implications for the function and regulation of photosynthesis.

eLife assessment

This boundary-crossing work on dandelion diaspore flight is an excellent demonstration of how to address fundamental questions about wind dispersal of plant seeds from biophysical and ecological perspectives. Both wind-tunnel experiments and models provide compelling evidence that the aerodynamics of dandelion diaspores change with the environment. Addition of local climate data enables the authors to make a convincing case about how the biophysical properties can scale up to affect dispersal across the landscape under different environmental conditions. In addition to the strong data, this is a clear, accessible, and very enjoyable read.

eLife assessment

This is a valuable study of Arabidopsis shoot apical meristem maintenance and organ initiation, defining the expression, interactions and functions of four transcription factors (SHR, SCR, JKD, and SCL23) whose roles were initially described in the root apical meristem. The imaging, genetics and FRET-FLIM evidence supporting the claims of the authors is comprehensive, extensive, and solid, although similar mechanisms, protein interactions, and gene regulatory interactions were previously reported in the root. The work will be of interest and importance for plant developmental biologists.

Evaluation Summary:

The chemical sensing mechanisms of plants, which are largely unknown, are a topic of broad interest. The authors hypothesise that plant chemical receptors may be transporter proteins or odorant binding proteins analogous to those found in animals. The authors have identified a list of plant proteins with possible odorant binding activity and they predict binding constants for relevant odorants. The calculated binding constants are generally very weak in comparison to known animal odorant binding proteins (i.e., would require much higher concentrations of odor for detection). The in silico investigation, while inspiring, leaves many open questions, for example whether or not there is evidence for functional analogy between plant and animal odorant binding proteins.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript.The reviewers remained anonymous to the authors.)

eLife assessment

This manuscript characterizes the localization and function of two proteins promoting division asymmetry in developing stomata of the grass Brachypodium distachyon. The authors demonstrate that the opposing polarity domains of these proteins are linked to cell division orientation. While both proteins have been studied previously in other systems, there was no prior evidence of cooperative functions in a single cell type, as shown here. With further clarification of some of the localization findings, this study will be of strong interest to plant cell biologists and those interested in asymmetric cell division generally.

eLife assessment

This paper, of relevance to a broad range of plant biologists and colleagues in the circandian field, reports important results that demonstrate circadian coordination of characteristic floral development in sunflower. The current manuscript includes convincing observations and possible hypotheses, but the ecological relevance of the temporally-controlled flower development is incompletely shown.

Evaluation Summary:

Engineering NLR proteins to improve disease resistance in crop plants is a major goal of the field. This study applies knowledge from structural and evolutionary studies of the rice NLR protein Pik-1 and cognate effector protein AVR-Pik to engineering of new disease resistance genes. The authors nicely demonstrate that it is indeed possible to engineer resistance proteins with broad recognition specificity for the rice blast fungus. The work is of interest to colleagues in synthetic biology, protein engineering and plant-pathogen interactions.

(This preprint has been reviewed by eLife. We include the public reviews from the reviewers here; the authors also receive private feedback with suggested changes to the manuscript. Reviewer #1 and Reviewer #2 agreed to share their name with the authors.)