Transcriptome sequencing and endogenous phytohormone analysis reveal new insights in CPPU controlling fruit development in kiwifruit (Actinidia chinensis)

Abstract

Kiwifruit (Actinidia chinensis) is a rich nutritious fruit crop owing to a markedly higher content of vitamin C and minerals. To promote fruit set and to increase the yield of kiwifruit, forchlorfenuron (CPPU) has been widely applied. However, the molecular details regarding CPPU controlling kiwifruit development, especially at the fastest fruit growth stage, remain unknown. In the present study, we measured the effect of CPPU on developmental regulation in red-fleshed kiwifruit (Actinidia chinensis 'Hongyang'). Additionally, a cytological analysis was performed to clarify the precise changes in the cell structure of the CPPU-treated kiwifruits. Moreover, the concentration of endogenous phytohormones, including indoleacetic acid (IAA), zeatin (ZT), gibberellic acid 3 (GA 3), and abscisic acid (ABA), were measured by Enzyme-linked Immunosorbent Assay (ELISA). Furthermore, RNA-Seq was performed to dissect the complicated molecular mechanisms, with a focus on biosynthesis, metabolism, and signaling compounds, such as endogenous hormones, sugars, and L-ascorbic acid. Our results demonstrated that CPPU treatment not only regulates the size and weight of a single fruit but also improves the quality in 'Hongyang' kiwifruit through the accumulation of both soluble sugar and vitamin C. It was also seen that CPPU regulates kiwifruit development by enhancing cell expansion of epidermal cells and parenchyma cells, while, promoting cell division of subepidermal cells. Additionally, CPPU significantly increased the gibberellin and cytokinin biosynthetic pathway and signaling, while repressing auxin and ABA biosynthetic pathway; thus, signaling plays an essential role in CPPU controlling kiwifruit development. Notably, transcriptomic analysis revealed that a total of 2244 genes, including 352 unannotated genes, were differentially expressed in kiwifruits because of CPPU treatment, including 127 transcription factors. These genes are mainly enriched in plant hormone signal transduction, photosynthesis, MAPK signaling pathway, starch and sucrose metabolism, and phenylpropanoid biosynthesis. Overall, our results highlight that CPPU regulation of kiwifruit development is mainly associated with an antagonistic and/or

A One-Step Polyphenol Removal Approach for Detection of Multiple Phytohormones from Grape Berry

“…Researchers have developed a variety of methods for the detection of phytohormones. Enzyme-linked immunosorbent assay (ELISA) and other immune assays are based on the ligand binding of the antibody to detect phytohormones with high sensitivity and specificity [33][34][35][36][37]. However, the specific recognition involved in immunoassays means that it is difficult to measure multiple types of hormones at the same time.…”

Transcriptomic and Metabolomic Studies Reveal Mechanisms of Effects of CPPU-Mediated Fruit-Setting on Attenuating Volatile Attributes of Melon Fruit

“…Plant growth regulators can be used as alternatives to artificial pollination to reduce labor costs. The cytokinin-active compound N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU), which is known to effectively induce parthenocarpic fruit set and enhance fruit enlargement by stimulating cell division and/or cell expansion [8], is applied in many kinds of fruits, including kiwifruit [9,10], blueberry [11], apples [12], pears [13], cherry [14], grape [15], and melon [16]. Although CPPU can promote the growth of fruit during the early stage, fruit quality might be different from the pollinated fruit during the later stage.…”

Metabolome and transcriptome analysis of flavor components and flavonoid biosynthesis in fig female flower tissues (Ficus carica L.) after bagging

“…The levels of auxin (IAA), gibberellin (GA), zeatin (ZR) and abscisic acid (ABA) in fig female flower tissues were determined by enzyme-linked immunoassay (ELISA) [ 47 ]. The enzyme immunoassay kit used for the assay was purchased from Yunnan Agricultural University, and the hormone assay tests were performed according to the described steps, and each sample was repeated three times.…”