Transcriptional control of local auxin distribution by the CsDFB1-CsPHB module regulates floral organogenesis in cucumber

Abstract

Plant cystatins are cysteine proteinase inhibitors that play key roles in defense responses. In this work, we describe an unexpected role for the cystatin-like protein DEFORMED FLORAL BUD1 (CsDFB1) as a transcriptional regulator of local auxin distribution in cucumber (Cucumis sativus L.). CsDFB1 was strongly expressed in the floral meristems, floral primordia, and vasculature. RNA interference (RNAi)-mediated silencing of CsDFB1 led to a significantly increased number of floral organs and vascular bundles, together with a pronounced accumulation of auxin. Conversely, accompanied by a decrease of auxin, overexpression of CsDFB1 resulted in a dramatic reduction in floral organ number and an obvious defect in vascular patterning, as well as organ fusion. CsDFB1 physically interacted with the cucumber ortholog of PHABULOSA (CsPHB), an HD-ZIP III transcription factor whose transcripts exhibit the same pattern as CsDFB1. Overexpression of CsPHB increased auxin accumulation in shoot tips and induced a floral phenotype similar to that of CsDFB1-RNAi lines. Furthermore, genetic and biochemical analyses revealed that CsDFB1 impairs CsPHB-mediated transcriptional regulation of the auxin biosynthetic gene YUCCA2 and the auxin efflux carrier PIN-FORMED1, and thus plays a pivotal role in auxin distribution. In summary, we propose that the CsDFB1-CsPHB module represents a regulatory pathway for local auxin distribution that governs floral organogenesis and vascular differentiation in cucumber.

The fruit glossiness locus, dull fruit (D), encodes a C2H2-type zinc finger transcription factor, CsDULL, in cucumber (Cucumis sativus L.)

“…Subcellular localization of CsDULL followed the procedure described by Nie et al . [ 48 ]. In brief, the full-length coding sequence of CsDULL without the stop codon was cloned from cDNA of 2073-1 and inserted in the 35S::GFP expression vector (owned by our laboratory) to form a CsDULL–GFP fusion construct.…”

Identification of long noncoding RNAs involved in plumule-vernalization of Chinese cabbage

“…The SAM status of many plants and various characteristics have been observed by slices to further determine the growth and development period of plants and the function of genes ( Takagi and Ueguchi, 2012 ; Cheng et al., 2018 ; Nie et al., 2021 ; Olas et al., 2021 ). We used toluidine blue to dye the SAM of Chinese cabbage under different plumule-vernalization treatments combined with different flowering times after plumule-vernalization and selected representative periods NV, V5, V15, V25, and T3 for RNA-seq ( Figure 1 ).…”

Transcriptome Analysis to Identify Genes Related to Flowering Reversion in Tomato

“…Flowering reversion is a phenomenon in which differentiated floral organs and tissues show a reversal of their development trajectories and enter vegetative growth again, which has been found in many species, including both monocotyledons and dicotyledons [ 8 , 44 ]. In the study of the molecular mechanism of floral organogenesis, scientists have found a variety of genes related to flowering reversion by investigating flowering reversion-related mutants and flower development [ 45 , 46 , 47 ]. However, flowering reversion is not simply the reversion of flower development but also may involve other novel biological regulatory processes.…”