Dehydroabietinal promotes flowering time and plant defense in Arabidopsis via the autonomous pathway genes FLOWERING LOCUS D, FVE, and RELATIVE OF EARLY FLOWERING 6

Abstract

Abietane diterpenoids are tricyclic diterpenes whose biological functions in angiosperms are largely unknown. Here, we show that dehydroabietinal (DA) fosters transition from the vegetative phase to reproductive development in Arabidopsis thaliana by promoting flowering time. DA’s promotion of flowering time was mediated through up-regulation of the autonomous pathway genes FLOWERING LOCUS D (FLD), RELATIVE OF EARLY FLOWERING 6 (REF6), and FVE, which repress expression of FLOWERING LOCUS C (FLC), a negative regulator of the key floral integrator FLOWERING LOCUS T (FT). Our results further indicate that FLD, REF6, and FVE are also required for systemic acquired resistance (SAR), an inducible defense mechanism that is also activated by DA. However, unlike flowering time, FT was not required for DA-induced SAR. Conversely, salicylic acid, which is essential for the manifestation of SAR, was not required for the DA-promoted flowering time. Thus, although the autonomous pathway genes FLD, REF6, and FVE are involved in SAR and flowering time, these biological processes are not interdependent. We suggest that SAR and flowering time signaling pathways bifurcate at a step downstream of FLD, REF6, and FVE, with an FLC-dependent arm controlling flowering time, and an FLC-independent pathway controlling SAR.

Salicylic Acid Treatment and Its Effect on Seed Yield and Seed Molecular Composition of Pisum sativum under Abiotic Stress

“…Differentially abundant proteins of interest that showed an increase in abundance in response to salicylic acid included trehalose 6-phosphate synthase that may promote seed filling [ 17 ], a lysine biosynthetic enzyme diaminopimelate epimerase with a putative role in salicylic acid-induced systemic acquired resistance [ 18 ], polyamine biosynthetic enzyme spermidine synthase and agmatine deiminase, an ortholog of protein phosphatase P2C78 which is a negative regulator of abscisic acid signaling and response to drought [ 19 ], MFT protein (regulates germination, mutant is hypersensitive to abscisic acid; [ 20 ]), two histone deacetylases and core histone-binding subunit MSI4 (AT2G19520) which ortholog promotes plant defense and flowering time in Arabidopsis [ 21 ], an ortholog of serine/arginine-rich splicing factor AT5G52040 mutation of which increases sensitivity to salt stress and abscisic acid [ 22 ], asparaginyl endopeptidase involved in processing of seed storage proteins, and an ortholog of glycine-rich RNA-binding protein RZ1A (overexpressors displayed earlier germination and better seedling growth under cold stress; [ 23 ]). Proteins that showed a decrease in abundance in response to salicylic acid included an ortholog of WD repeat-containing protein VIP3 (mutant shows early flowering; [ 24 ]), auxin activating enzyme that hydrolyzes IAA-amino acid conjugates, and an ortholog of a key enzyme in myo-inositol biosynthesis pathway AT2G22240 (inositol-3-phosphate synthase, mutant plants are compromised in resistance to pathogens; [ 25 ]).…”

RSI1/FLD and its epigenetic target RRTF1 are essential for the retention of infection memory in Arabidopsis thaliana

“…Our work identified a possible infection memory module in plants comprised of RSI1 and RRTF1. SAR is compromised in RSI1 loss‐of‐function mutants while local resistance is not impacted (Chowdhury et al., 2020; Singh et al., 2013; Singh, Banday, & Nandi, 2014; Singh, Roy, et al., 2014). Infiltration of petiole exudates obtained from pathogen‐inoculated leaves of WT and rsi1 mutant plants to activate SAR demonstrated that RSI1 functions at the distal tissue downstream of the perception of mobile signals (Singh et al., 2013).…”

“…The rsi1 mutant bears a lesion in the FLOWERING LOCUS D ( FLD ) gene. In the rsi1 mutant, the generation of SAR mobile signals is not defective, but the process of SAR development subsequent to the perception of these signals in the systemic tissue is perturbed (Chowdhury et al., 2020; Singh et al., 2013). RSI1 codes for a putative histone demethylase and limits the expression of the flowering suppression gene FLOWERING LOCUS C ( FLC ) (He et al., 2003).…”

Floral induction pathways: Decision making and determination in plants to flower-A comprehensive review

“…DBP1 (DNA-binding protein phosphatase 1) acts in autonomous and photoperiod pathways of flowering by modifying transcript levels of many critical integrators such as CO, LFY, SOC1, FLC, and FT [66]. Dehydroabietinal mediates upregulation of the autonomous pathway involved genes such as FLD, FVE, and REF6 resulting in FLC repression [67]. Furthermore, two KH domain proteins KHZ1 and KHZ2 are supposed to act as heterodimers, leading to the repression of FLC pre-mRNA splicing efficiency [68].…”