An ICln homolog contributes to osmotic and low‐nitrate tolerance by enhancing nitrate accumulation in Arabidopsis

Abstract

Nitrate (NO 3 −) is a source of plant nutrients and osmolytes, but its delivery machineries under osmotic and low-nutrient stress remain largely unknown. Here, we report that AtICln, an Arabidopsis homolog of the nucleotide-sensitive chloride-conductance regulatory protein family (ICln), is involved in response to osmotic and low-NO 3 − stress. The gene AtICln, encoding plasma membrane-anchored proteins, was upregulated by various osmotic stresses, and its disruption impaired plant tolerance to osmotic stress. Compared with the wild type, the aticln mutant retained lower anions, particularly NO 3 − , and its growth retardation was not rescued by NO 3 − supply under osmotic stress. Interestingly, this mutant also displayed growth defects under low-NO 3 stress, which were accompanied by decreases in NO 3 − accumulation, suggesting that AtICln may facilitate the NO 3 − accumulation under NO 3 − deficiency. Moreover, the low-NO 3 − hypersensitive phenotype of aticln mutant was overridden by the overexpression of NRT1.1, an important NO 3 − transporter in Arabidopsis low-NO 3 − responses. Further genetic analysis in the plants with altered activity of AtICln and NRT1.1 indicated that AtICln and NRT1.1 play a compensatory role in maintaining NO 3 − homeostasis under low-NO 3 − environments.These results suggest that AtICln is involved in cellular NO 3 − accumulation and thus determines osmotic adjustment and low-NO 3 − tolerance in plants.

Insights into the role of alternative splicing in plant temperature response

“…Furthermore, a more recent study has shown that AtICln is important for plant tolerance to osmotic stress, in addition to also being central to nitrate ion accumulation (Chu et al, 2021). According to the observations of both studies, AtICln subcellular localization and the molecular function seem to diverge depending on the environmental conditions (S. Chu et al, 2021); however, further research and experimental data are required to further clarify the function of AtICln with the hopes of confirming its role in the plant methylosome.…”

A secreted fungal effector suppresses rice immunity through host histone hypoacetylation

“…The coding sequences of UvSec1171 and OsHDA701 were cloned into the BiFC vectors pSPYCE(MR) and pSPYNE(R) 173, respectively. The resulting constructs encoding the UvSec117-cYFP and OsHDA701-nYFP fusion proteins were coinfiltrated into N. benthamiana leaves following Chu et al (2021) (YFP, yellow fluorescent protein). A Zeiss LSM 510 Meta confocal microscope (Carl Zeiss) was used to examine the YFP fluorescence signals.…”

Vacuolar nitrate efflux requires multiple functional redundant nitrate transporter in Arabidopsis thaliana

“…Nitrate serves not only as a nitrogen nutrient but also as a signaling molecule (Wang et al, 2018;Hu et al, 2019). Other studies also showed that nitrate acts as an osmotic solute (Smirnoff and Stewart, 1985;Song et al, 2006;Ozfidan-Konakci et al, 2020;Chu et al, 2021;Ozturk et al, 2021). To maintain a stable cytoplasmic nitrate concentration, plants store the excess nitrate in vacuoles.…”