The Role of EjSPL3, EjSPL4, EjSPL5, and EjSPL9 in Regulating Flowering in Loquat (Eriobotrya japonica Lindl.)

Abstract

The age pathway is important for regulating flower bud initiation in flowering plants. The major regulators in this pathway are miR156 and SPL transcription factors. To date, SPL genes have been identified in many species of plants. Loquat, as a woody fruit tree of Rosaceae, is unique in flowering time as it blooms in winter. However, the study of its SPL homologous genes on the regulation mechanism of flowering time is still limited. In this study, four SPL homologs—EjSPL3, EjSPL4, EjSPL5, and EjSPL9—are cloned from loquat, and phylogenetic analysis showed that they share a high sequence similarity with the homologues from other plants, including a highly conserved SQUAMOSA promoter binding protein (SBP)-box domain. EjSPL3, EjSPL4, EjSPL5 are localized in the cytoplasm and nucleus, and EjSPL9 is localized only in the nucleus. EjSPL4, EjSPL5, and EjSPL9 can significantly activate the promoters of EjSOC1-1, EjLFY-1, and EjAP1-1; overexpression of EjSPL3, EjSPL4, EjSPL5, and EjSPL9 in wild-type Arabidopsis thaliana can promote flowering obviously, and downstream flowering genes expression were upregulated. Our work indicated that the EjSPL3, EjSPL4, EjSPL5, and EjSPL9 transcription factors are speculated to likely participate in flower bud differentiation and other developmental processes in loquat. These findings are helpful to analyze the flowering regulation mechanism of loquat and provide reference for the study of the flowering mechanism of other woody fruit trees.

An Integrative Analysis of Transcriptome, Proteome and Hormones Reveals Key Differentially Expressed Genes and Metabolic Pathways Involved in Flower Development in Loquat

“…Furthermore, AP2 is regulated by LFY, and plays a central role in promoting floral meristem determinacy [32][33][34]. Previously, it was also reported that FT, SOC1, SPL4, SPL5, and SPL9 orthologs are upregulated in flower bud differentiation in loquat [2,35,36]. These similar results indicate that the RNA-Seq data and expression changes of the DEGs involved in floral transition are reliable in our study.…”

Heterotrimeric G-protein α subunit (RGA1) regulates tiller development, yield, cell wall, nitrogen response and biotic stress in rice

“…4 ). These results were observed throughout the life cycles of wild type and rga1 mutants, which is in line with the earlier reports 29 , 30 . To understand the role of RGA1 in the tiller development, we developed protein–protein interaction networks using experimentally validated interactors reported in tillering phenotypes in rice.…”

“…At the physiological level, the processes regulated by Gα include ABA mediated stomatal opening 21 , stomatal density regulation 22 , sphingolipid signaling 23 , sugar signaling 24 , light-stimulation of nitrate reductase gene expression 25 and phenylalanine and ABA production 26 , 27 . In rice, the reported roles of Gα include abiotic stresses 28 including salt stress 29 , drought 30 , photo-oxidation 31 , plant immunity 32 , plant growth 33 , grain size 34 , nitrate response 35 and brassinosteroid signaling 13 , 36 .…”

“…However, there are no comprehensive studies on the genome-wide role of G-proteins in any crop plant, despite their suggested roles in agronomically important traits. The availability of a natural mutant of the Gα subunit in rice 41 provided such an opportunity for a long time and yet, the only large scale studies that attempted on it have been limited to photoprotection and photoavoidance 31 and abiotic stresses 28 , 29 . The present study was aimed at a comprehensive genomewide analysis of the rga1 mutant in comparison to its corresponding wild type to reveal many hitherto unknown roles of rga1 , including regulation of many agronomically important traits and to identify their underlying processes.…”

Hierarchical Action of Mulberry miR156 in the Vegetative Phase Transition

“…Researchers also found that the expression of SPLs decreased under heavy fruit load in Citrus clementina , and Citrus SPL was able to promote flowering independent of photoperiod in Arabidopsis [ 13 ]. EjSPL4, EjSPL5, and EjSPL9 could significantly activate the promoters of EjSOC1-1 , EjLFY-1 , and EjAP1-1 in loquat and the over-expression of EjSPL3 , EjSPL4 , EjSPL5 , and EjSPL9 in A. thaliana could promote obvious flowering [ 14 ]. However, the hierarchical action of miR156 in vegetative phase growth in perennial woody plants is still unknown.…”