Genome of Solanum pimpinellifolium provides insights into structural variants during tomato breeding
Wang et al. present a high-quality chromosome-scale genome sequence of SP LA2093. Genome comparison identifies more than 92,000 structural variants (SVs) between LA2093 and the modern cultivar, Heinz 1706. Genotyping these SVs in ~600 representative tomato accessions identifies alleles under selection during tomato domestication, improvement and modern breeding, and discovers numerous SVs overlapping genes known to regulate important breeding traits such as fruit weight and lycopene content. Expression quantitative trait locus (eQTL) analysis detects hotspots harboring master regulators controlling important fruit quality traits, including cuticular wax accumulation and flavonoid biosynthesis, and SVs contributing to these complex regulatory networks. The LA2093 genome sequence and the identified SVs provide rich resources for future research and biodiversity-based breeding.
Fungi took a unique evolutionary route to multicellularity: Seven key challenges for fungal multicellular life - ScienceDirect
In contrast to animals and plants, how multicellularity evolved in fungi and how it compares to the general principles distilled from the study of more widely studied model systems, has received little attention. This review broadly discusses multicellular functioning and evolution in fungi. Nagy et al. focus on how fungi solved some of the common challenges associated with the evolution of multi-celled organisms and what unique challenges follow from the peculiar, filamentous growth form of fungi. Nagy et al. identify and discuss seven key challenges for fungal multicellular growth: apical growth, compartmentalization, long-distance mass transport, controlling mutational load, cell-to-cell communication, differentiation and adhesion.
Fungal Biology Reviews
The association between early career informal mentorship in academic collaborations and junior author performance
AlShebli et al. study mentorship in scientific collaborations, where a junior scientist is supported by potentially multiple senior collaborators, without them necessarily having formal supervisory roles. However, many commentators say they studied them badly.
A network of transcriptional repressors modulates auxin responses
The hormone auxin is a key signal for plant growth and development that acts through the AUXIN RESPONSE FACTOR (ARF) transcription factors. A subset of these, the conserved class A ARFs, are transcriptional activators of auxin-responsive target genes that are essential for regulating auxin signalling throughout the plant lifecycle. Although class A ARFs have tissue-specific expression patterns, how their expression is regulated is unknown. Truskina et al. show, by investigating chromatin modifications and accessibility, that loci encoding these proteins are constitutively open for transcription.
Coordination between microbiota and root endodermis supports plant mineral nutrient homeostasis
Salas-González et al. demonstrate that genes controlling endodermal function in the model plant Arabidopsis thaliana contribute to the plant microbiome assembly. They characterize a regulatory mechanism of endodermal differentiation driven by the microbiota with profound effects on nutrient homeostasis. Furthermore, they demonstrate that this mechanism is linked to the microbiota’s capacity to repress responses to the phytohormone abscisic acid in the root. Their findings establish the endodermis as a regulatory hub coordinating microbiota assembly and homeostatic mechanisms.
Fire and biodiversity in the Anthropocene
Fire has played a prominent role in the evolution of biodiversity and is a natural factor shaping many ecological communities. However, the incidence of fire has been exacerbated by human activity, and this is now affecting ecosystems and habitats that have never been fire prone or fire adapted. Kelly et al. review how such changes are already threatening species with extinction and transforming terrestrial ecosystems and discuss the trends causing changes in fire regimes. They also consider actions that could be taken by conservationists and policy-makers to help sustain biodiversity in a time of changing fire activity.
Divergence in a stress-associated gene regulatory network underlies differential growth control in the Brassicaceae family
The use of marginal lands in agriculture is increasingly necessary to support the global human population. Elevated salinity frequently occurs in degraded soils and hinders their use due to the negative impact salt stress has on plant growth. While the hormonal networks controlling growth have been extensively characterized in stress-sensitive plants, it is unclear how these pathways are rewired in plants that maintain growth in extreme environments. Sun et al. have compared the physiological and molecular responses of four closely related members of the Brassicaceae family including two salt-tolerant species (Shrenkiella parvula and Eutrema salsugineum) and two salt-sensitive species (Sisymbrium irio and Arabidopsis thaliana) to the salt stress-induced hormone, abscisic acid (ABA). While ABA inhibits root growth in most species, they uncovered substantial growth-promoting effects in Shrenkiella parvula, due to an enhancement in cell elongation.
The End of Botany
Biologists unable to recognize common plants, and a decline in botany students, faculty, courses, university departments, and herbaria, highlight the current erosion of botany. How did we reach this crisis, knowing that plants form the basis for life? What are the causes? What can we do to reverse it?
Trends in Plant Science
Amazon rainforest photosynthesis increases in response to atmospheric dryness
Earth system models predict that increases in atmospheric and soil dryness will reduce photosynthesis in the Amazon rainforest, with large implications for the global carbon cycle. Using in situ observations, solar-induced fluorescence, and nonlinear machine learning techniques, Green et al. show that this is not necessarily the case: In many of the wettest parts of this region, photosynthesis and biomass tend to increase with increased atmospheric dryness, despite the associated reductions in canopy conductance to CO2. These results can be largely explained by changes in canopy properties, specifically, new leaves flushed during the dry season have higher photosynthetic capacity than the leaves they replace, compensating for the negative stomatal response to increased dryness.
Tip‐to‐base xylem conduit widening as an adaptation: causes, consequences, and empirical priorities - Olson
In the stems of terrestrial vascular plants studied to date, the diameter of xylem water‐conducting conduits D widens predictably with distance from the stem tip L approximating D ∝ Lb, with b ≈ 0.2. Because conduit diameter is central for conductance, it is essential to understand the cause of this remarkably pervasive pattern. Olson et al. give reason to suspect that tip‐to‐base conduit widening is an adaptation, favored by natural selection because widening helps minimize the increase in hydraulic resistance that would otherwise occur as an individual stem grows longer and conductive path length increases.