Pepper Novel Pseudo Response Regulator Protein CaPRR2 Modulates Drought and High Salt Tolerance

Abstract

Plants modify their internal states to adapt to environmental stresses. Under environmental stress conditions, plants restrict their growth and development and activate defense responses. Abscisic acid (ABA) is a major phytohormone that plays a crucial role in the osmotic stress response. In osmotic stress adaptation, plants regulate stomatal closure, osmoprotectant production, and gene expression. Here, we isolated CaPRR2 – encoding a pseudo response regulator protein – from the leaves of pepper plants (Capsicum annuum). After exposure to ABA and environmental stresses, such as drought and salt stresses, CaPRR2 expression in pepper leaves was significantly altered. Under drought and salt stress conditions, CaPRR2-silenced pepper plants exhibited enhanced osmotic stress tolerance, characterized by an enhanced ABA-induced stomatal closing and high MDA and proline contents, compared to the control pepper plants. Taken together, our data indicate that CaPRR2 negatively regulates osmotic stress tolerance.

Pepper stress‐associated protein 14 is a substrate of CaSnRK2.6 that positively modulates abscisic acid‐dependent osmotic stress responses

“…However, no ubiquitination activity was detected in the present study (Figure S8). On the other hand, we could observe the transcriptional activity in the anterior AN1‐like zinc finger domain (Figure 3d) and that CaSAP14 could activate the expression of stress‐responsive genes, including CaOSR1 and CaRAB18 , which are also induced by ABA or osmotic stress (Lim et al., 2022; Lim, Lim, & Lee, 2021; Park et al., 2016). These findings indicate that CaSAP14 can function as a transcription factor, not an E3 ligase, in pepper plants.…”

“…For physiological assays, namely, those for electrolyte leakage and the contents of proline and MDA, the roots of 4‐week‐old pepper plants were soaked in 200 m m NaCl for 16 h, and 2‐week‐old Arabidopsis plants were subjected to 250 m m NaCl solution for the same time. Thereafter, the leaves of pepper and Arabidopsis plants were collected for the respective assays, as previously described (Bae et al., 2021; Lim, Lim, & Lee, 2021; Luo et al., 2019).…”

Tomato salt‐responsive pseudo‐response regulator 1, SlSRP1, negatively regulates the high‐salt and dehydration stress responses

“…Our previous studies have identified CaPRR2 in pepper plants as the PRR2 homolog gene and characterized its negative role in osmotic stress tolerance (Lim et al, 2021). The expression levels of CaPRR2…”

“…In plants, the precise biological functions of the PRR genes in responses and Arabidopsis APRR5/APRR7 are involved in ABA signaling (Lim et al, 2021, Yang et al, 2021. Here, we investigated the role of pseudo-response regulator SlSRP1 in tomato plants using the VIGS system and elucidated that SlSRP1 has a negative effect on ABA-mediated osmotic stress responses.…”

“…In circadian clock‐mediated ABA signaling, PRR5 and PRR7 interact with ABI5, a core transcription factor in ABA signaling, resulting in the modulation of ABI5 transcriptional activity (Yang et al, 2021). Although PRRs are expected to play a key role in the crosstalk between the circadian rhythm system and ABA signaling in the context of abiotic stress responses, little information has been reported regarding PRRs (Nakamichi et al, 2009; Lim et al, 2021).…”