GIGANTEA regulates PAD4 transcription to promote pathogen defense against Hyaloperonospora arabidopsidis in Arabidopsis thaliana

Abstract

Plants have evolved a network of complex signaling pathways that allow them to cope with the fluctuations of internal and external environmental cues. GIGANTEA (GI), a well-known, highly conserved plant nuclear protein, has been shown to regulate multiple biological functions in plants such as circadian rhythm, light signaling, cold tolerance, hormone signaling, and photoperiodic flowering. Recently, the role of GI in disease tolerance against different pathogens has come to light; however, a detailed mechanism to understand the role of GI in pathogen defense remains largely unexplained. Here, we report that GIGANTEA is upregulated upon infection with a virulent oomycete pathogen, Hyaloperonospora arabidopsidis ( Hpa ), in Arabidopsis thaliana accession Col-0. To investigate the role of GI in Arabidopsis defense, we examined the pathogen infection phenotype of gi mutant plants and found that gi-100 mutant was highly susceptible to Hpa Noco2 infection. Notably, the quantitative real-time PCR showed that PHYTOALEXIN DEFICIENT4 ( PAD4 ) and several PAD4-regulated downstream genes were downregulated upon Noco2 infection in gi-100 mutant as compared to Col-0 plants. Furthermore, the chromatin immunoprecipitation results show that GI can directly bind to the intronic region of the PAD4 gene, which might explain the mechanism of GI function in regulating disease resistance in plants. Taken together, our results suggest that GI expression is induced upon Hpa pathogen infection and GI can regulate the expression of PAD4 to promote resistance against the oomycete pathogen Hyaloperonospora arabidopsidis in Arabidopsis thaliana .

GIGANTEA supresses wilt disease resistance by down-regulating the jasmonate signaling in Arabidopsis thaliana

“…Therefore, in gi mutants, the SA content as well as the ICS1 transcript levels are high under uninfected conditions. After the plant was attacked by the pathogen, there was an increased transcript expression of PAD4, which corroborated with the fact that GI binds with the PAD4 intronic region upon pathogen infection (Singh, 2022). The level of ICS1 transcript increased, as a result of which the amount of SA metabolites also increased in the plant.…”

“…Late-flowering mutants, such as gi-1 , mediator 8 ( med8 ), phytochrome and flowering time1 ( pft1 ), auxin response factor 2 ( arf2 ), and myc2 , have also been found to promote resistance to F. oxysporum in plants ( Kidd et al., 2009 ; Gangappa and Chattopadhyay, 2010 ; Lyons et al., 2015a ; Lyons et al., 2015b ), implying a role of flowering genes in modulating the defense pathways in plants. Despite plenty of studies that describe possible functions of GI in abiotic stress response, little is known about its involvement in biotic stress tolerance ( Lyons et al., 2015a ; Kundu and Sahu, 2021 ; Singh, 2022 ).…”

Re-engineering a lost trait:IPD3, a master regulator of arbuscular mycorrhizal symbiosis, affects genes for immunity and metabolism of non-host Arabidopsis when restored long after its evolutionary loss

“…AM symbiosis affects flowering time in host plants, and the circadian clock is implicated in maintenance of the symbiosis itself as well as AM-mediated abiotic stress resistance (Hernandez and Allen, 2013; Lee et al, 2019; Bennett and Meek, 2020; Liu et al, 2022). In Arabidopsis , circadian rhythm genes are also known to act in microbiome construction, pathogen defense, development, and abiotic stress (Lee et al, 2005; Nakamichi et al, 2016; Newman et al, 2022; Xu et al, 2022; Singh, 2022a; Singh, 2022b). Remarkably, in mosses, the sole group of nonAM plants that retain CSP genes, IPD3 specifically has been shown to mediate a stress-responsive reproductive transition (Kleist et al, 2022).…”

GIGANTEA regulates lateral root formation by modulating auxin signaling in Arabidopsis thaliana

“…The qRT-PCR was performed as published previously with minor modifications. 23 For RNA isolation, ~50 mg of At seedlings after were harvested with liquid nitrogen in the same light condition. Total RNA was isolated using Qiagen Plant RNeasy mini kit followed by cDNA preparation from 1 μg of RNA of each sample using Bio-Rad iScriptTM Reverse Transcription Super-mix.…”

“…The PCR mix and thermocycler program for the qPCR were similar to those done by Singh, 2022. 23 Transcripts level were normalized with ACTIN . Each qRT-PCR reaction was performed in three biological replicates and all data were presented as mean ± SEM.…”