reSeArcH Article
GIPCs, osmosensing OSCA1 and components yet to be defined may
work together to integrate both ionic and osmotic aspects of salt into
the salt Ca^2 + signalling pathway in plants.
Much progress has been made over the last three decades in under-
standing the phenomenon of [Ca^2 +]i elevation in response to abiotic
and biotic stimuli in plants^5 ,^7 ,^41 ,^42. Ca^2 +-imaging-based genetic screens
have led to the identification of only a few receptors or sensors, includ-
ing DORN1 for external ATP, OSCA1 for osmotic stress, and LORE
for lipopolysaccharides^17 ,^43 ,^44. These Ca^2 +-related receptors could
be classified into three groups: (1) receptor-like kinases, including
NFR1, NFP (also known as NFR5) and DMI2 (also known as SYMRK)
for Nod factors, FLS2 for flg22, EFR for elf18 and elf26, PEPR1 for
AtPep1, and FER for rapid alkalinization factor, as well as DORN1
and LORE; (2) the receptor channel OSCA1; and (3) transmembrane
receptors^8 ,^41. Ca^2 + channels that are not receptors or sensors but are
responsible for Ca^2 + increases have also been found, such as DMI1,
Pollux and Castor and CNGC15 for Nod factors, CNGC14 for auxin
and CNGC18 for the pollen tube^41 ,^45 ,^46 , and GLRs for wounding and
sperm chemotaxis^47 ,^48. It is plausible to speculate that GIPC-associated
Ca^2 + channels belong to this category. In animals, Ca^2 +-related recep-
tors comprise G-protein coupled receptors, receptor tyrosine kinases,
and receptor channels^12 ,^49 , and animal salt sensors are receptor chan-
nels^13 –^16. Therefore, GIPC-mediated salt sensing in plants differs from
all these receptors found in animals and plants. Note that GIPCs are
receptors for pathogenic necrosis and ethylene-inducing peptide 1-like
proteins in eudicot but not monocot plants^50 , and gangliosides are
receptors for axon–myelin interactions in animals^32.
In conclusion, our results shed light on salt sensing in plants, high-
light the importance of GIPCs—as a specific class of sphingolipids—for
the regulation (and modulation) of signalling processes at the plasma
membrane, and underscore the functional versatility of various lipids in
different evolutionary branches of life. Our findings could also provide
potential molecular genetic targets for engineering salt-resistant crops.
Online content
Any methods, additional references, Nature Research reporting summaries, source
data, extended data, supplementary information, acknowledgements, peer review
information; details of author contributions and competing interests; and state-
ments of data and code availability are available at https://doi.org/10.1038/s41586-
019-1449-z.
Received: 25 April 2018; Accepted: 3 July 2019;
Published online 31 July 2019.
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