A molecular network for functional versatility of HECATE transcription factors

Abstract

During the plant life cycle, diverse signaling inputs are continuously integrated and engage specific genetic programs depending on the cellular or developmental context. Consistent with an important role in this process, HECATE (HEC) basic helix-loop-helix transcription factors display diverse functions, from photomorphogenesis to the control of shoot meristem dynamics and gynoecium patterning. However, the molecular mechanisms underlying their functional versatility and the deployment of specific HEC subprograms remain elusive. To address this issue, we systematically identified proteins with the capacity to interact with HEC1, the best-characterized member of the family, and integrated this information with our data set of direct HEC1 target genes. The resulting core genetic modules were consistent with specific developmental functions of HEC1, including its described activities in light signaling, gynoecium development and auxin homeostasis. Importantly, we found that HEC genes also play a role in the modulation of flowering time, and uncovered that their role in gynoecium development may involve the direct transcriptional regulation of NGATHA1 (NGA1) and NGA2 genes. NGA factors were previously shown to contribute to fruit development, but our data now show that they also modulate stem cell homeostasis in the shoot apical meristem. Taken together, our results delineate a molecular network underlying the functional versatility of HEC transcription factors. Our analyses have not only allowed us to identify relevant target genes controlling shoot stem cell activity and a so far undescribed biological function of HEC1, but also provide a rich resource for the mechanistic elucidation of further context-dependent HEC activities.

How plants grow up

“…Normal single central subapical localization of WUS begins in the embryo and is stably maintained through cytokinin signaling (Leibfried et al ; Gordon and Chickarmane ; Chickarmane et al ; Adibi et al ; Meng et al ; Snipes et al ). WUS induction of HECATE transcription factor genes, the activity of which reduces auxin signaling, is critical for meristem integrity (Schuster et al ; Gaillochet et al ), consistent with reports that both auxin treatment and inhibition of auxin transport cause fasciation (Gorter ; Fambrini et al ). Taken together, cell division orientation regulated by a centrally defined WUS expression domain and corresponding hormonal balance, appears essential for cylindrical axis integrity and stem growth.…”

Genome-wide analyses of the bHLH gene family reveals structural and functional characteristics in the aquatic plantNelumbo nucifera

“…Other members of subgroup 10 and subgroup 13 have also showed regulatory abilities (Leivar et al, 2008; Zumajo-Cardona, Ambrose & Pabón-Mora, 2017; Cifuentes-Esquivel et al, 2014). Members of subgroups 15b and 16 have been predicted to be involved in diverse processes (Mai et al, 2015; Ferguson et al, 2017; Gaillochet et al, 2018; Zhu et al, 2016). NnbHLHs in subgroup 21 should negatively control thermospermine biosynthesis and xylem differentiation (Cai et al, 2016; Yamamoto & Takahashi, 2017), while members of subgroup 24 may play an essential role in establishing vascular cells (Ohashi-Ito, Matsukawa & Fukuda, 2013).…”

Gene co-expression analysis of tomato seed maturation reveals tissue-specific regulatory networks and hubs associated with the acquisition of desiccation tolerance and seed vigour

“…A closer look at the gene list revealed seven genes encoding helicases and topoisomerases associated with DNA repair and the stability of repetitive sequences within the genome. The small ME17 characterizing late embryo maturation from 72 DAF onwards did not exhibit revealing GO terms (Additional le 3: Table S2) but we noted the presence of four orthologs of HECATE genes, a transcription factor with versatile functions throughout development [47] and ABA2, involved in ABA synthesis. ME13, containing genes that were highly expressed between 15 and 42 DAF, re ecting a transcriptional program related to embryogenesis (Fig.…”