Identification and Expression Analysis of Gretchen Hagen 3 (GH3) in Kiwifruit (Actinidia chinensis) During Postharvest Process

Abstract

In plants, the Gretchen GH3 (GH3) protein is involved in free auxin (IAA) and amino acid conjugation, thus controlling auxin homeostasis. To date, many GH3 gene families have been identified from different plant species. However, the GH3 gene family in kiwifruit (Actinidia chinensis) has not been reported. In this study, 12 AcGH3 genes were identified, phylogenetic analysis of AtGH3 (Arabidopsis), SlGH3 (Solanum lycopersicum), and AcGH3 provided insights into various orthologous relationships among these proteins, which were categorized into three groups. Expression analysis of AcGH3 genes at different postharvest stages suggested limited or no role for most of the AcGH3 genes at the initiation of fruit ripening. AcGH3.1 was the only gene exhibiting ripening-associated expression. Further study showed that the expression of AcGH3.1 gene was induced by NAA (1-naphthylacetic acid, auxin analogue) and inhibited by 1-MCP (1-methylcyclopropene, ethylene receptor inhibitor), respectively. AcGH3.1 gene silencing inhibited gene expression and delayed fruit softening in kiwifruit. The results indicate that AcGH3.1 may play an important role in the softening process of fruits. Analysis of the AcGH3.1 promoter revealed the presence of many cis-elements related to hormones, light, and drought. The determination of GUS (β-Galactosidase) enzyme activity revealed that promoter activity increased strikingly upon abscisic acid (ABA), ethylene, or NAA treatment, and significantly decreased with salicylic acid (SA) treatment. The present study could help in the identification of GH3 genes and revelation of AcGH3.1 gene function during postharvest stages, which pave the way for further functional verification of the AcGH3.1 gene.

Maize specialized metabolome networks reveal organ-preferential mixed glycosides

“…The conjugation of aspartate or glutamate to indole-3-acetic acid (IAA), the core structure of the indolics, and to phenylacetic acid (PAA), the core structure of the phenylethanoids, is an important aspect of auxin homeostasis in plants [63] , [64] . Of these four conjugates, only IAA aspartate and PAA aspartate were found in this study.…”

Regulation of Postharvest Tomato Fruit Ripening by Endogenous Salicylic Acid

“…There are plenty of reports showing that preharvest or postharvest application of SA delays the ripening of fruit and vegetables such as banana (Srivastava and Dwivedi, 2000 ), tomato fruit (Ruifen, 2001 ; Mandal et al, 2018 ), kiwi (Zhang et al, 2003 ), peach (Han et al, 2002 ; Tareen et al, 2012 ), strawberry (Lolaei et al, 2012 ), mango (Hong et al, 2014 ), etc. SA probably delays ripening by inhibition of ET biosynthesis at the level of 1-aminocyclopropane-1-carboxylic acid (ACC) (Leslie and Romani, 1988 ).…”

Genome-wide identification of GH3 genes in Brassica oleracea and identification of a promoter region for anther-specific expression of a GH3 gene

“…Over-expression of AtGH3.5 ( WES1 ), which is induced by treatment of abscisic acid and SA, as well as auxin, leads to auxin resistant phenotypes [ 17 ]. In various plants, important roles played by plant GH3 enzymes have also been demonstrated: nodule numbers and sizes in soybean [ 18 ], resistance to Xanthomonas bacteria in citrus [ 19 ], drought and salt tolerance in cotton [ 20 ], and fruit softening in kiwi [ 21 ], were shown to be affected by GH3 gene expressions.…”