KHZ1 and KHZ2, novel members of the autonomous pathway, repress the splicing efficiency of FLC pre-mRNA in Arabidopsis

Abstract

As one of the most important events during the life cycle of flowering plants, the floral transition is of crucial importance for plant propagation and requires the precise coordination of multiple endogenous and external signals. There have been at least four flowering pathways (i.e. photoperiod, vernalization, gibberellin, and autonomous) identified in Arabidopsis. We previously reported that two Arabidopsis RNA-binding proteins, KHZ1 and KHZ2, redundantly promote flowering. However, the underlying mechanism was unclear. Here, we found that the double mutant khz1 khz2 flowered late under both long-day and short-day conditions, but responded to vernalization and gibberellin treatments. The late-flowering phenotype was almost completely rescued by mutating FLOWERING LOCUS C (FLC) and fully rescued by overexpressing FLOWERING LOCUS T (FT). Additional experiments demonstrated that the KHZs could form homodimers or interact to form heterodimers, localized to nuclear dots, and repressed the splicing efficiency of FLC pre-mRNA. Together, these data indicate that the KHZs could promote flowering via the autonomous pathway by repressing the splicing efficiency of FLC pre-mRNA.

BcMF30a and BcMF30c, Two Novel Non-Tandem CCCH Zinc-Finger Proteins, Function in Pollen Development and Pollen Germination in Brassica campestris ssp. chinensis

“…AtC3H17 plays multiple roles in plant development and stress response [ 37 , 38 ]. KHZ1 and KHZ2 could mediate flowering and senescence in Arabidopsis [ 39 , 40 ]. DCM1 is a five CCCH motif-containing protein in rice that is involved in male meiotic cytokinesis [ 26 ].…”

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

“…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]. Thus, FLC functions as a floral induction node in Arabidopsis as multiple mechanisms act in FLC levels' autonomous regulation.…”

Widespread premature transcription termination ofArabidopsis thalianaNLR genes by the spen protein FPA

“…Additional RNA binding proteins of the autonomous pathway, such as FLK (Mockler et al, 2004), KHZ1/KHZ2 (Yan et al, 2019), FLY (Dai et al, 2020) and GRP7/8 (Streitner et al, 2008) were also detected. Not all members of the autonomous pathway are RNA binding proteins, and we detected FVE co-purifying with FPA.…”

“…The benefit of NLR function to hosts is disease resistance. However, there are costs to increased NLR gene number or activity that can lead to detrimental autoimmunity (or hyperimmunity) (Rodriguez et al, 2016), restriction of association with beneficial microbes (Yang et al, 2010), and a general reduction in fitness (Tian et al, 2003). In some cases, epistatic interactions involving NLRs can result in autoimmunity that is detected as hybrid weakness or necrosis (Li et al, 2020).…”