Transcriptional changes in litchi (Litchi chinensis Sonn.) inflorescences treated with uniconazole

Abstract

In Arabidopsis, treating shoots with uniconazole can result in enhanced primary root elongation and bolting delay. Uniconazole spraying has become an important cultivation technique in controlling the flowering and improving the fruit-setting of litchi. However, the mechanism by which uniconazole regulates the complicated developmental processes in litchi remains unclear. This study aimed to determine which signal pathways and genes drive the responses of litchi inflorescences to uniconazole treatment. We monitored the transcriptional activity in inflorescences after uniconazole treatment by Illumina sequencing technology. The global expression profiles of uniconazole-treated litchi inflorescences were compared with those of the control, and 4051 differentially expressed genes were isolated. KEGG pathway enrichment analysis indicated that the plant hormone signal transduction pathway served key functions in the flower developmental stage under uniconazole treatment. Basing on the transcriptional analysis of genes involved in flower development, we hypothesized that uniconazole treatment increases the ratio of female flowers by activating the transcription of pistil-related genes. This phenomenon increases opportunities for pollination and fertilization, thereby enhancing the fruit-bearing rate. In addition, uniconazole treatment regulates the expression of unigenes involved in numerous transcription factor families, especially the bHLH and WRKY families. These findings suggest that the uniconazole-induced morphological changes in litchi inflorescences are related to the control of hormone signaling, the regulation of flowering genes, and the expression levels of various transcription factors. This study provides comprehensive inflorescence transcriptome data to elucidate the molecular mechanisms underlying the response of litchi flowers to uniconazole treatment and enumerates possible candidate genes that can be used to guide future research in controlling litchi flowering.

Genome-wide identification and expression analysis of carotenoid cleavage oxygenase genes in Litchi (Litchi chinensis Sonn.)

“…Uniconazole treatment of litchi inflorescences can control flowering and improve fruit-setting in litchi [ 29 ]. LcCCD4 , LcCCD4c2 , LcCCD8a , LcNCED2, and LcNCED3 showed down-regulated expression obviously in the entire inflorescences after uniconazole spraying, decreased by 1.72, 1.53, 15.97, 2.80, and 3.18 times separately.…”

“…(3) Three stages of peel samples of ‘Nuomici’ litchi: green, yellow and red peel stage, accession number is SRP047115 ( https://www.ncbi.nlm.nih.gov/sra/?term=SRP047115 ) [ 28 ]. (4) The entire inflorescences samples on 28 days after the uniconazole treatment, accession number is SRP092890 ( https://www.ncbi.nlm.nih.gov/sra/?term=SRP092890 ) [ 29 ]. (5) The fruit samples on 2d, 4d and 7d after fruit abscission of ‘Wuye’ litchi caused by girdling plus defoliation treatment (GPD), accession number is SRA234477 ( https://www.ncbi.nlm.nih.gov/sra/?term=SRA234477 ) [ 30 ].…”

Genome-Wide Identification and Expression Analysis of MADS-Box Family Genes in Litchi (Litchi chinensis Sonn.) and Their Involvement in Floral Sex Determination

“…According to the phylogenetic relationship analysis ( Figure 3 ), LcMADS95 ( LcAP1 ), LcMADS75 ( LcAP3-1 ), LcMADS45 ( LcAP3-2 ), LcMADS50 ( LcPI ), LcMADS65 ( LcAG ), LcMADS51 ( LcSTK ), LcMADS11 ( LcSHP ), LcMADS100 ( LcSEP1 ), LcMADS94 ( LcSEP2 ), LcMADS91 ( LcSEP3 ), and LcMADS73 ( LcSEP4 ) represented ABCDE genes. A previous study observed the regulation of GA and its inhibitor (uniconazole) in litchi sex determination [ 17 ], and JA has shown an antagonistic role to GA in flower development [ 18 ]. Hence, we tested the response of genes involved in the ABCDE model to these two hormones in this study.…”

Uniconazole Augments Abscisic Acid in Promoting Somatic Embryogenesis in Cotton (Gossypium hirsutum L.)

“…Uniconazole is a member of the triazole family that is known to bind to the active sites of cytochrome P450 enzymes by both coordinating to the heme-iron atom and interacting with neighboring amino acid residues ( Saito et al, 2006 ). Despite the fact that it has the side effect of inhibiting the biosynthesis of gibberellic acid (GA) and brassinosteroid (BR) ( Min et al, 1999 ), uniconazole can protect plants from various stresses, in addition to various other functions, such as enhancing the levels of carotenoid and chlorophyll ( Fletcher and Hofstra, 1990 ), promoting the accumulation of starch ( Liu et al, 2015 ), improving primary root elongation and delay bolting in Arabidopsis , controlling the flowering, enhancing fruit setting ( Wei et al, 2017 ), elevating yield components in crop plants ( Zhou and Ye, 1996 ; Ahmad et al, 2018 ), and changing the content of endogenous hormones ( Zhang et al, 2007 ).…”