A Splice-Variant Imbalance of Reticulon-like Protein 16 (RTNLB16) Disrupts Growth and Decreases Sensitivity to ABA and Dark-Induced Senescence in Arabidopsis.

Authors

Tami Khazma, Dikla Levi, Hiba Waldman Ben-Asher, Tamir Shechtman, Gal Nisan, Gad Miller

Published in

Plants (Basel, Switzerland). Volume 15. Issue 13. Jun 30, 2026. Epub Jun 30, 2026.

Abstract

Reticulon-like proteins shape the endoplasmic reticulum (ER) membrane network, yet the developmental and physiological roles of individual plant reticulon isoforms remain poorly understood. Here, we characterize an Arabidopsis RTNLB16 T-DNA allele, rtnlb16-1, that exhibits severe photoperiod-dependent growth retardation and chlorosis. Molecular analysis revealed that rtnlb16-1 is not a simple loss-of-function mutant: the T-DNA insertion deletes the 5' region required for RTNLB16 splice variant 7, while a CaMV35S enhancer associated with the insertion drives overexpression of the remaining splice variants. This misexpression is enhanced under long-day photoperiods and reduced under continuous low light, paralleling the severity of the mutant phenotype and its partial rescue. RTNLB16.5-GFP localized mainly to the tubular ER network and punctate cell-boundary structures consistent with plasmodesmata-associated ER. Neither overexpression of RTNLB16 isoforms 1-6 nor CRISPR-Cas9 disruption of major RTNLB16 isoforms reproduced the rtnlb16-1 phenotype, supporting a model in which altered splice-variant stoichiometry, rather than simple loss or gain of function, underlies the developmental defects. Transcriptome profiling showed that rtnlb16-1 undergoes extensive photoperiod-dependent transcriptional reprogramming, including changes in defense, hormone-response, senescence, photosynthesis, and iron/redox-associated gene networks. Physiologically, rtnlb16-1 displayed enhanced recovery from dark-induced senescence, while both rtnlb16-1 and rtnlb16-2 showed reduced sensitivity to exogenous abscisic acid during germination. Together, these findings suggest that balanced expression of RTNLB16 splice variants is important for normal growth and for coordinating ER-associated stress, hormone, and senescence responses in Arabidopsis.

PMID:
42452228
Bibliographic data and abstract were imported from PubMed on 13 Sep 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.