CsSPL functions as an adaptor between HD‐ZIP III and CsWUS transcription factors regulating anther and ovule development in Cucumis sativus (cucumber)

Abstract

Anther and ovule genesis preconditions crop fertilization and fruit production; however, coordinative regulation of anther and ovule development and underlying molecular pathways remain largely elusive. Here, we found that SPOROCYTELESS (SPL)/NOZZLE (NZZ) expression was nearly abolished in a Cucumis sativus (cucumber) mutant with severely defective anther and ovule development. CsSPL was expressed specifically in the developing anthers and ovules. Knock-down of CsSPL reduced male and female fertility with malformed pollen and suppressed ovule development. Importantly, CsSPL directly interacted with CsWUS (WUSCHEL) in the nucellus and YABBY family genes in integuments, and positively regulated CsWUS expression, meanwhile the HD-ZIP III gene CsPHB (PHABULOSA), expressed specifically in the nucellus, promoted CsSPL expression by binding to the CsSPL promoter. Thus, CsSPL acts as an adaptor to link CsPHB and CsWUS functioning, underpinning a previously unidentified regulatory pathway orchestrating sex organ development in planta. In addition, auxin accumulation was reduced in the reproductive organs of CsSPL knock-down plants. Biochemical analyses further showed that CsSPL stimulated the expression of AUXIN RESPONSE FACTOR 3 (CsARF3), and was positively regulated by CsARF13 during reproductive organ development, indicating sequential interactions of CsSPL with auxin signaling components in orchestrating anther and ovule development.

Identification of lncRNAs involved in rice ovule development and female gametophyte abortion by genome-wide screening and functional analysis

“…The differentially expressed lncRNAs may affect the female gametophyte by affecting the auxin response. As important transcriptional regulatory elements, transcription factors play crucial roles in the reproductive process of female plants [44–46]. In our data, LTCONS_00004164, LTCONS_00070807, LTCONS_00011471, and LTCONS_00042441 were significantly downregulated; LTCONS_00004164 and LTCONS_00070807 targeted two MYB transcription factor genes, Osmyb4 (LOC_Os01g50110) and Osmyb55 (LOC_Os05g48010), respectively, and LTCONS_00011471 and LTCONS_00042441 targeted the two bZIP transcription factor genes OsbZIP09 (LOC_Os01g59760) and OsbZIP24 (LOC_Os02g58670), respectively.…”

Differential Gene Expression Caused by the F and M Loci Provides Insight Into Ethylene-Mediated Female Flower Differentiation in Cucumber

“…Notably, the aforementioned genes, CsIAA29 , CsCRC , and CsFUL , displayed similar expression trends in a previous study investigating the fruit length in cucumbers ( Jiang et al, 2015 ), thus suggesting that these genes may play pivotal roles in early fruit development. Interestingly, CsSPL , which encodes a protein that directly interacts with CsWUS (WUSCHEL) and positively regulates CsWUS and CsARF3 ( AUXIN RESPONSE FACTOR 3) expression ( Liu et al, 2018 ), showed a 4.4-fold higher expression in M12 and H34. Thus, CsSPL not only regulates sex organ development by interacting with auxin signaling, as recently reported, but may also participate in the process of sex differentiation in cucumbers.…”

YABBY Genes in the Development and Evolution of Land Plants

“…Bioinformatic methods have enabled the identification of homologues of "vegetative" YABBYs in the genomes of tomato (Solanum lycopersicum L., nine YABBY genes; [54]), apple (Malus pumila Mill., 13 YABBY genes; [66]), Chinese cabbage (Brassica rapa L. ssp. pekinensis; [67]), cucumber (Cucumis sativus L.; [68]), snapdragon (Antirrhinum majus L.; [69,70]), and grape (Vitis pseudoreticulata, two YABBY genes; [71]).…”