Новости науки и практики // Октябрь 2020

Ammonium triggers formation of lateral roots

Meier et al. show that local ammonium supply stimulates the accumulation of shoot-derived auxin in the root vasculature and promotes lateral root emergence to build a highly branched root system. Activities of pH and auxin reporters indicate that ammonium uptake mediated by ammonium transporters acidifies the root apoplast, which increases pH-dependent import of protonated auxin into cortical and epidermal cells overlaying lateral root primordia, and subsequently promotes their emergence from the parental root. Thereby, ammonium-induced and H+-ATPase-mediated acidification of the apoplast allows auxin to bypass the auxin importers AUX1 and LAX3. In nitrogen-deficient plants, auxin also accumulates in the root vasculature but a more alkaline apoplast leads to retention of auxin in these tissues and prevents lateral root formation.

https://www.eurekalert.org/pub_releases/2020-09/liop-atf091120.php

Cellular compass' guides stem cell division in plants

Biologists observing the formation of leaves noticed the nuclei moved in bewildering ways. Further investigation uncovered proteins that act as compasses and motors, guiding the divisions of individual cells to create the overall pattern of the leaf.

https://www.sciencedaily.com/releases/2020/09/200917180403.htm

The regulation of ethylene biosynthesis: a complex multilevel control circuitry
In this review, Pattyn et al. bring together historical reports and the latest findings on the complex regulation of the ethylene biosynthesis pathway in plants.

https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.16873

When phosphorus levels are low, mycorrhizae outcompete root hairs in maize

The two adaptations both aid in nutrient uptake, but may work against each other.

https://www.botany.one/2020/09/when-phosphorus-levels-are-low-mycorrhizae-outcompete-root-hairs-in-maize/

The morphogenesis of fast growth in plants 
Wade et al. conducted a phylogenetic comparative experiment with 74 grass species, conceptualising morphogenesis as the branching and growth of repeating modules. They aimed to establish whether faster growth in C4 and annual grasses, compared to C3 and perennial grasses, came from the faster growth of individual modules or higher rates of module initiation.

https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.16892

Pluripotent Pericycle Cells Trigger Different Growth Outputs by Integrating Developmental Cues into Distinct Regulatory Modules
During post-embryonic development, the pericycle specifies the stem cells that give rise to both lateral roots (LRs) and the periderm, a suberized barrier that protects the plant against biotic and abiotic stresses. Comparable auxin-mediated signaling hubs regulate meristem establishment in many developmental contexts; however, it is unknown how specific outputs are achieved. Using the Arabidopsis root as a model, Xiao et al. show that while LR formation is the main auxin-induced program after de-etiolation, plants with age become competent to form a periderm in response to auxin. The establishment of the vascular cambium acts as the developmental switch required to trigger auxin-mediated periderm initiation.

https://www.cell.com/current-biology/fulltext/S0960-9822(20)31243-4

Direct fluorescence imaging of cell walls in plant roots and stems

Microscopy methods developed in the 1960s are still commonly used in plant science today but new low-cost techniques offer big advantages.

https://academic.oup.com/aobpla/article/12/4/plaa032/5864598

Photosynthesis: basics, history and modelling

Here some of the discoveries related to photosynthesis, such as the existence of two light reactions and two photosystems connected by an electron transport ‘chain’ (the Z-scheme), chemiosmotic hypothesis for ATP synthesis, water oxidation clock for oxygen evolution, steps for carbon fixation, and finally the diverse mechanisms of regulatory processes, such as ‘state transitions’ and ‘non-photochemical quenching’ of the excited state of chlorophyll a.

https://academic.oup.com/aob/article/126/4/511/5602694

Thicker leaves, thicker cell walls, low mesophyll conductance
Do differences in structure and anatomy impact mesophyll conductance and photosynthesis of rice leaves?

https://academic.oup.com/aobpla/article/12/4/plaa028/5860164

Когда появился фагоцитоз?

Фагоцитоз — очень важный тип клеточной активности, позволяющий клеткам целиком поглощать друг друга. Когда же именно он появился? Появление фагоцитоза, безусловно, стало для земных экосистем революционным событием.

https://elementy.ru/novosti_nauki/433693/Kogda_poyavilsya_fagotsitoz

Single-Cell Resolution of Lineage Trajectories in the Arabidopsis Stomatal Lineage and Developing Leaf
Scientists uncovered distinct models of cell state differentiation within Arabidopsis leaf tissue by leveraging single-cell transcriptomics and molecular genetics. Their findings resolved underlying heterogeneity within cell states of the flexible epidermal stomatal lineage, which appear to exist along a continuum, with progressive cell specification. Beyond the early stages of the lineage, we discovered that the core transcriptional regulator SPEECHLESS is required for cell fate commitment to yield stomatal guard cells.

https://www.biorxiv.org/content/10.1101/2020.09.08.288498v1

New rules for algae species classification

A team of evolutionary biologists and ecologists has a new idea for how scientists should classify algae species.

https://www.sciencedaily.com/releases/2020/09/200914165541.htm

How plants ensure regular seed spacing

Biologists have examined how seed formation is coordinated with fruit growth. They explain the genetic control mechanisms underlying the process.

https://www.sciencedaily.com/releases/2020/09/200911110756.htm

Scientists find a new chemical to induce plant defences

ssODNs (single-stranded DNA oligodeoxynucleotides ) are capable of inducing protection against pathogens through the activation of defence genes and promotion of stomatal closure.

https://www.botany.one/2020/09/scientists-find-a-new-chemical-to-induce-plant-defences/

Genome duplications as evolutionary adaptation strategy

Researchers study relationship of morphological variation and biological diversity in plants.

https://www.eurekalert.org/pub_releases/2020-09/uoh-gda092320.php

Melatonin metabolism, signaling, and possible roles in plants

Melatonin is a multifunctional biomolecule found in both animals and plants. In this
review, the biosynthesis, levels, signaling, and possible roles of melatonin and its
metabolites in plants is summarized.

https://onlinelibrary.wiley.com/doi/full/10.1111/tpj.14915

High-Temperature Tolerance of Flowers

The reasons for high-temperature caused disorders are not necessarily clear, but high temperature influences part of gene expressions involved in flowering time (FT, Flowering Locus T) and pigment synthesis (such as CHS, chalcone synthase).

https://link.springer.com/chapter/10.1007/978-981-15-2156-0_12