LOWER TEMPERATURE 1 Enhances ABA Responses and Plant Drought Tolerance by Modulating the Stability and Localization of C2-Domain ABA-Related Proteins in Arabidopsis

Abstract

Plasma membrane-associated abscisic acid (ABA) signal transduction is an integral part of ABA signaling. The C2-domain ABA-related (CAR) proteins play important roles in the recruitment of ABA receptors to the plasma membrane to facilitate ABA signaling. However, how CAR proteins are regulated remains unclear. In this study, we conducted a genetic screen for mutants with altered leaf transpiration and identified an uncharacterized protein, LOWER TEMPERATURE 1 (LOT1), which regulates the dynamic localization and stability of CAR proteins. The lot1 mutant had a lower leaf temperature as compared with the wild type due to higher transpiration. We found that LOT1 physically interacts with CAR9 , and ABA reduces LOT1-CAR9 interaction in the nucleus, likely via Ca 2+ , resulting in increased localization of CAR9 to the plasma membrane. We further found that the stability of CAR9 is affected by LOT1 less CAR9 proteins were accumulated and more were ubiquitinated in lot1. While the lot1, car9 and lot1 car9 mutants were hyposensitive to ABA, the hyposensitive phenotype of lot1 could be rescued by CAR9 overexpression. Collectively, our study reveals that LOT1 regulates plant tolerance to drought stress by affecting ABA signaling through regulating the stability and dynamic localization of CAR9.

The OsERF115/AP2EREBP110 Transcription Factor Is Involved in the Multiple Stress Tolerance to Heat and Drought in Rice Plants

“…DroughtSpotter is an automated irrigation gravitropic system. Recently, this system was used to examine the water loss by transpiration of the lot1 Arabidopsis mutant under drought stress and analyze the WUE of the drought-tolerant osphyb rice mutant [21,74]. When we assessed the whole-plant WUE by the ratio between the plant biomass gain (% of initial area) and water irrigated throughout the experimental period, the OsERF115/AP2EREBP110-OE rice exhibited higher WUE than WT plants (Figure 4f).…”

A nonspecific lipid transfer protein, StLTP10, mediates resistance to Phytophthora infestans in potato

“…Here, we found that StLTP10 physically interacts with ABA receptor PYL4. In Arabidopsis , the C2‐domain ABA‐related (CAR) family of small proteins is involved in recruitment of PYR/PYL/RCAR receptors to the membrane and regulates ABA sensitivity to elicit plant responses to a changing environment (Diaz et al, 2016; Rodriguez et al, 2014; Qin et al, 2019). In this study, the interaction between StLTP10 and PYL4 was detected in the plasma membrane.…”

Seasonal change in response of stomatal conductance to vapor pressure deficit and three phytohormones in three tree species

“…In particular, ABA plays a major role in regulating stomatal function in adaptation to various environmental stresses, such as drought, cold, air pollutants, etc. [24][25][26][27] Inadequate stomatal closure at high vapor pressure deficit may be mediated by abscisic acid. 30 In addition, other phytohormones also contribute to stomatal aperture regulation, such as auxin, cytokinin, ethylene and salicylic acid.…”

“…Increased levels of abscisic acid (ABA) while a plant is under stress promote stomatal closure and/or inhibit stomata opening in order to avoid excessive water loss. [24][25][26][27][28][29] The response of g s to VPD is correlated to the level of ABA. 30 The other phytohormones, including indole-3-acetic acid (IAA) and Gibberellins (GAs), are known to antagonize the effects of ABA on stomatal behavior.…”