Microbiome manipulation by a soil-borne fungal plant pathogen using effector proteins
Snelders et al. show that the previously identified virulence effector VdAve1, secreted by the fungal plant pathogen Verticillium dahliae, displays antimicrobial activity and facilitates colonization of tomato and cotton through the manipulation of their microbiomes by suppressing antagonistic bacteria. Moreover, they show that VdAve1, and also the newly identified antimicrobial effector VdAMP2, are exploited for microbiome manipulation in the soil environment, where the fungus resides in absence of a host.
The rise of angiosperms pushed conifers to decline during global cooling
Condamine et al. show that the decline of conifers is strongly and directly linked to the increasing diversity of flowering plants. Both the fossil record and molecular data converge in clarifying the effects of abiotic or biotic factors on the speciation and extinction rates of conifers. These results imply that long-term biological interactions through clade competition can play a more important role in the rise and demise of major organism groups than mass extinctions.
Forest and woodland replacement patterns following drought-related mortality
Batllori et al. provide an emerging picture of postdrought ecological trajectories based on field indicators of forest dynamics. Replacement patterns following mortality indicate limited short-term persistence of predrought dominant tree species, highlighting the potential for major ecosystem reorganization in the coming decades. The great variability of the observed dynamics within and among species reinforces the primary influence of drought characteristics and ecosystem legacies, modulated by land use, management, and past disturbances, on ongoing drought-related species turnover and their potential implications for future forest biodiversity and ecosystem services.
Optical topometry and machine learning to rapidly phenotype stomatal patterning traits for QTL mapping in maize
Stomata are adjustable pores on leaf surfaces that regulate the trade-off of CO2 uptake with water vapor loss, thus having critical roles in controlling photosynthetic carbon gain and plant water use. The lack of easy, rapid methods for phenotyping epidermal cell traits have limited the use of quantitative, forward and reverse genetics to discover the genetic basis of stomatal patterning. A new high-throughput epidermal cell phenotyping pipeline is presented here and used for quantitative trait loci (QTL) mapping in field-grown maize. The locations and sizes of stomatal complexes and pavement cells on images acquired by an optical topometer from mature leaves were automatically determined.
Agricultural diversification promotes multiple ecosystem services without compromising yield
Enhancing biodiversity in cropping systems is suggested to promote ecosystem services, thereby reducing dependency on agronomic inputs while maintaining high crop yields. Tamburini et al. assess the impact of several diversification practices in cropping systems on above- and belowground biodiversity and ecosystem services by reviewing 98 meta-analyses and performing a second-order meta-analysis based on 5160 original studies comprising 41,946 comparisons between diversified and simplified practices. Overall, diversification enhances biodiversity, pollination, pest control, nutrient cycling, soil fertility, and water regulation without compromising crop yields.
A meta-analysis of biological impacts of artificial light at night
Using a new database of published studies, Sanders et al. show that exposure to artificial light at night induces strong responses for physiological measures, daily activity patterns and life history traits. We found particularly strong responses with regards to hormone levels, the onset of daily activity in diurnal species and life history traits, such as the number of offspring, predation, cognition and seafinding (in turtles). So far, few studies have focused on the impact of artificial light at night on ecosystem functions. The breadth and often strength of biological impacts we reveal highlight the need for outdoor artificial night-time lighting to be limited to the places and forms—such as timing, intensity and spectrum—where it is genuinely required by the people using it to minimize ecological impacts.
Nature Ecology & Evolution
Global food system emissions could preclude achieving the 1.5° and 2°C climate change targets
To have any hope of meeting the central goal of the Paris Agreement, which is to limit global warming to 2°C or less, our carbon emissions must be reduced considerably, including those coming from agriculture. Clark et al. show that even if fossil fuel emissions were eliminated immediately, emissions from the global food system alone would make it impossible to limit warming to 1.5°C and difficult even to realize the 2°C target. Thus, major changes in how food is produced are needed if we want to meet the goals of the Paris Agreement.
CLAVATA Signaling Ensures Reproductive Development in Plants across Thermal Environments
Jones et al. show that reproductive development under different thermal conditions requires the integration of multiple pathways regulating auxin-dependent flower production. In colder/ambient temperatures, the receptor complex CLAVATA2/CORYNE (CLV2/CRN) is necessary for continuous flower outgrowth during inflorescence development. CLV2/CRN signaling is independent of CLAVATA1 (CLV1)-related receptor signaling but involves the CLAVATA3 INSENSITIVE RECEPTOR KINASE (CIK) family co-receptors, with higher order cik mutant combinations phenocopying clv2/crn flower outgrowth defects. Developing crn inflorescences display reduced auxin signaling, and restoration of auxin biosynthesis is sufficient to restore flower outgrowth in colder and ambient temperatures. In contrast, at higher temperatures, both clv2/crn signaling and heat-induced auxin biosynthesis via YUCCA family genes are synergistically required to maintain flower development.
A reporter for noninvasively monitoring gene expression and plant transformation
He et al. construct a new reporter RUBY that converts tyrosine to vividly red betalain, which is clearly visible to naked eyes without the need of using special equipment or chemical treatments. They show that RUBY can be used to noninvasively monitor gene expression in plants. Furthermore, they show that RUBY is an effective selection marker for transformation events in both rice and Arabidopsis. The new reporter will be especially useful for monitoring cellular activities in large crop plants such as a fruit tree under field conditions and for observing transformation and gene expression in tissue culture under sterile conditions.
The host exocyst complex is targeted by a conserved bacterial type III effector protein that promotes virulence
Michalopoulou et al. show that Xanthomonas campestris, the causal agent of black rot disease, delivers the highly conserved effector XopP that interacts with host's EXO70 protein. EXO70 is an essential component of the exocyst complex with a role in plant immunity. The XopP/EXO70 interaction is specific and inhibits exocyst-dependent exocytosis without activating a specific plant NLR receptor that guards EXO70. In this way, Xanthomonas efficiently inhibits the host's PAMP-triggered immunity (PTI) by blocking exocytosis of PR1, callose deposition and the FLS2 immunity-receptor translocation to the plasma membrane, promoting successful infection.