Articles in 2022

It’s time once more for the announcement of the winners of the Nobel Prizes, which again fail to include any researchers who work on plants. However, that does not mean to say that the prizes have no relevance to plant biologists.

Extant asterids comprise over 80,000 species of flowering plants. A fossil fruit from western North America shows that the lamiid clade of asterids diverged over 80 million years ago.

SnRK1 is a key metabolic sensor that controls plant development and stress responses. This study integrates phosphoproteomics, affinity purification coupled to mass spectrometry, proximity labelling and crosslinking mass spectrometry to obtain more insight into its upstream regulation and downstream target processes.

Sweet potato weevils (SPWs) pose one of the most significant challenges to sweet potato production. This study identifies two major SPW-resistant genes, SPWR1/2, and provides new insights into the mechanism of sweet potato defence against SPWs.

Plant cell wall pectin has a homogalacturonan or rhamnogalacturonan backbone. Incomplete knowledge of RG-I biosynthetic enzymes has impeded in vitro pectin synthesis and pectin structure and function studies. Here, RGGAT1 is identified as a GT116 RG-I backbone biosynthetic galacturonosyltransferase that produces polymeric RG-I backbone when expressed with GT106 RG-I rhamnosyltransferases.

The glycosyltransferase enzyme RGGAT1 is shown to catalyse the addition of galacturonic acid into rhamnogalacturonan I, the backbone of the plant cell wall, with implications for in vitro pectin synthesis.

Nitrate is a nutrient and a signal. Membrane protein NRT1.1 reflects this duality as both a nitrate transporter and sensor. A new perception mechanism has just been discovered: transcription factor NLP7 is also a nitrate sensor. Thus, two distinct but interacting systems perceive nitrate. Are there others?

Duplication of KCBP, which encodes a plant-specific microtubule-based kinesin motor, occurs solely in legumes of the clade that form symbiosomes. The nodule-enriched KCBP (nKCBP) is co-opted by rhizobia to control central vacuole morphogenesis in symbiotic cells, thus achieving symbiosome development and nitrogen fixation.

Root hairs have long been considered to elongate exclusively by so-called tip growth, in which the new building material is deposited at the root hair apex. Using a set of newly developed imaging experiments, we revealed that root hair shank expansion can substantially contribute to total root hair growth.

This study uncovered a gene duplication in legumes that produces a nodule-enriched nKCBP protein, a plant-specific kinesin motor, and found that rhizobia co-opts nKCBP to control vacuole morphogenesis in symbiotic cells, thus achieving successful endosymbiosis.

Guard cell outward rectifying potassium (GORK) channel activity is associated with channel clustering at the guard cell membrane. We show that clustering and gating both depend on an extended ‘antenna’ of bound channel voltage sensors. Uncoupling clustering and gating facilitates K⁺ flux, accelerating stomatal movements in environments typical for plants in the field.

Using trait-based optimality theory that unifies stomatal responses and acclimation of plants to changing environments, this study builds a model of the coupling of CO₂ and water vapour exchanges through the leaves. This successfully predicts the simultaneous decline in carbon assimilation, stomatal conductance and photosynthetic capacity during progressive droughts.

For a long time, root hairs were believed to expand via tip growth only. This study shows that the root hair shank undergoes considerable expansion too, which coincides with the deposition of new cell wall material in the shank.

Stomatal guard cells regulate CO₂ entry to the leaf for photosynthesis but respond slowly to fluctuating light, thus reducing carbon assimilation and water use efficiencies. Substantial efficiency gains are realized by engineering the gating of a K⁺ channel native to the guard cells.

Intracellular H₂O₂ has emerged as a central player in signalling and stress acclimation, but how specificity is achieved remains elusive. Cytosolic peroxiredoxins play a decisive role as they sense H₂O₂ and transmit the oxidation signal through the formation of disulfide bridges, leading to stomatal closure that reduces pathogen entry.

Pathogen perception in plants is mediated by immune receptors that detect specific pathogen molecules. Members of one diverse receptor family that occurs in all land plants form a structurally conserved activation complex with a shared signalling mechanism.