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Phylogenetic tree of the auxin response factors. The DNA binding domains of the auxin response factors (ARF) from apple (green), strawberry (lilac), Arabidopsis (black) and tomato (red) were aligned using MUSCLE and phylogenetic trees were built using neighbour joining. Bootstraps of 1000 iterations are given. At: Arabidopsis thaliana, Fv: Fragaria vesca, Md: Malus x domestica, Pp: Physcomitrella patens, Sl: Solanum lycopersicum
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Auxin is an important phytohormone for fleshy fruit development, having been shown to be involved in the initial signal for fertilisation, fruit size through the control of cell division and cell expansion, and ripening related events. There is considerable knowledge of auxin-related genes, mostly from work in model species. With the apple genome n...
Citations
... It is now widely acknowledged that seeds contain a variety of hormones, such as cytokinin, GA, and auxins, which regulate fruit size and encourage the growth of surrounding tissues (Ozga et al.,14). During the stages of fruit development, when cell division is followed by a phase of cell expansion, auxin and cytokinin levels increase in the developing seed (Devoghalaere et al.,5). ...
... Significant work has also been performed to explore the mechanisms underlying fruit development in other crops. In apple, a strong QTL for fruit weight was linked to Auxin Response Factor 106 (MdARF106) (Devoghalaere et al., 2012). Silencing of SlIAA7 in tomato resulted in thicker pericarp tissue, and thus, larger fruits (Su et al., 2014). ...
The cultivated strawberry, Fragaria ×ananassa, is a recently domesticated fruit species of economic interest worldwide. As such, there is significant interest in continuous varietal improvement. Genomics-assisted improvement, including the use of DNA markers and genomic selection have facilitated significant improvements of numerous key traits during strawberry breeding. CRISPR/Cas-mediated genome editing allows targeted mutations and precision nucleotide substitutions in the target genome, revolutionizing functional genomics and crop improvement. Genome editing is beginning to gain traction in the more challenging polyploid crops, including allo-octoploid strawberry. The release of high-quality reference genomes and comprehensive subgenome-specific genotyping and gene expression profiling data in octoploid strawberry will lead to a surge in trait discovery and modification by using CRISPR/Cas. Genome editing has already been successfully applied for modification of several strawberry genes, including anthocyanin content, fruit firmness and tolerance to post-harvest disease. However, reports on many other important breeding characteristics associated with fruit quality and production are still lacking, indicating a need for streamlined genome editing approaches and tools in Fragaria ×ananassa. In this review, we present an overview of the latest advancements in knowledge and breeding efforts involving CRISPR/Cas genome editing for the enhancement of strawberry varieties. Furthermore, we explore potential applications of this technology for improving other Rosaceous plant species.
... During early fruit development, gibberellins and auxins promote cell division and expansion, determining fruit size (Devoghalaere et al. 2012;El-Sharkawy et al. 2017;He and Yamamuro 2022). Other hormones, such as cytokinins, brassinosteroids, jasmonic acids and strigolactones are also involved (Kumar et al. 2014). ...
Reproductive development of fruiting trees, including mango (Mangifera indica L.), is limited by non-structural carbohydrates. Competition for sugars increases with cropping, and consequently, vegetative growth and replenishment of starch reserves may reduce with high yields, resulting in interannual production variability. While the effect of crop load on photosynthesis and the distribution of starch within the mango tree has been studied, the contribution of starch and sugars to different phases of reproductive development requires attention. This review focuses on mango and examines the roles of non-structural carbohydrates in fruiting trees to clarify the repercussions of crop load on reproductive development. Starch buffers the plant’s carbon availability to regulate supply with demand, while sugars provide a direct resource for carbon translocation. Sugar signalling and interactions with phytohormones play a crucial role in flowering, fruit set, growth, ripening and retention, as well as regulating starch, sugar and secondary metabolites in fruit. The balance between the leaf and fruit biomass affects the availability and contributions of starch and sugars to fruiting. Crop load impacts photosynthesis and interactions between sources and sinks. As a result, the onset and rate of reproductive processes are affected, with repercussions for fruit size, composition, and the inter-annual bearing pattern.
... It is now widely acknowledged that seeds contain a variety of hormones, such as cytokinin, GA, and auxins, which regulate fruit size and encourage the growth of surrounding tissues (Ozga et al.,14). During the stages of fruit development, when cell division is followed by a phase of cell expansion, auxin and cytokinin levels increase in the developing seed (Devoghalaere et al.,5). ...
The present study was carried out in two successive years to evaluate the comparative efficacy of CPPU and NAA combination in improving the yield attributes of Langra mango. Higher fruit drop and low fruit retention are the most critical constraints for mango production under north Indian conditions. Fruit drop starts occurring just after fruit set and continues till harvest, leading to substantial economic loss to the growers. The foliar application of CPPU 10 ppm + NAA 20 ppm and CPPU 20 ppm + NAA 30 ppm immediately after the fruit set resulted in a significant reduction in fruit drop in comparison to the control (water spray). Various physical attributes like endocarp size (5.16 cm), pedicel length (1.20 cm), pedicel thickness (4.02 mm), fruit weight (248.12 g), fruit size (7.46 cm width and 9.83 cm length), fruit volume (243.52 cc), and specific gravity (1.02) got improved with CPPU 10 ppm + NAA 20 ppm followed by CPPU 20 ppm + NAA 30 ppm than the control. In conclusion, the spray of CPPU 10 ppm + NAA 20 ppm proved to be an effective treatment for managing fruit drop and improving yield attributes in Langra mango.
... Fruit set and development processes depend on auxin, gibberellin, and cytokinin. The application of these substances in the fruit set process will have the effect of thinning flowers and fruits [17] . The application of these plant hormones also has a regulatory effect on fruit size, fruit shape, and nutrient content. ...
... The application of transcriptome is important to reveal the effects of the exogenous hormone on fruit development and the ripening processes. Previous studies have focused on the exogenous NAA in the development of the ovary and fruit set by transcriptome analysis [17,20] , however, the application of exogenous NAA throughout the fruit development period has rarely been investigated. ...
... Plant hormone-based thinners, auxin, gibberellin, and cytokinin affect the fruit setting and development process, and their application during fruit setting will play a role in chemical thinning agents. The application of these plant hormones also has a regulatory effect on fruit size, fruit shape, and nutrient content [17] . In our study, we found that NAA significantly inhibited the fruit development process. ...
The optimal load capacity provides sustainable production and high quality in 'Fuji' apple production. Determining optimal crop loads with simple and affordable thinning methods is critical for apple. We set different load capacities on different apple tree rootstocks and evaluated their effects on tree development, fruit yield and quality. The optimal load capacity for vigorous stock, dwarfing rootstock, and dwarfing interstock were 240, 90, and 100 for apples above 80 mm in diameter, respectively. To explore the optimal strategies of diverse fruit thinning agents (carbaryl, 6-BA, NAA, and Metamitron) used in the 'Fuji' apple tree, we assess from thinning agents' types, varying spraying concentrations, and application time in the most widely used dwarfing interstock. The results showed that the best use of fruit thinning agents is 2,000 mg/L carbaryl at 10 d after flowering could significantly reduce fruit set rate and improve the fruit quality in the dwarfing interstock. During the research, only the fruit thinner NAA treatment suppresses fruit development. Thus, we performed the transcriptome analysis on the NAA-treated and control fruits at 60 (FS1), 90 (FS2), 120 (FS3), and 150 (FS4) days after flowering stages to investigate the potential transcriptional regulations of NAA on fruit development and ripening. Transcriptome results showed that genes related to fruit expansion (expansin A15, expansin B3), phytohormone-related genes (HVA22C, PRE1, AHP1, etc.), fruit coloring-related genes (PAL), and many ripening-related transcription factors (EIN3, ERF, ARF, etc.) might be regulated by exogenous NAA. Our results provide an important reference for the sustainable production and optimal use of fruit thinning agents.
... Fruit size is a particularly important factor in determining fruit quality and is known to be regulated by several genes or locus. According to several QTL studies, significantly associated regions have been found in almost all LGs, which means that fruit size is determined by complex regulatory pathway (Liebhard et al., 2003;Kenis et al., 2008;Devoghalaere et al., 2012). In addition to the QTL study, genetic factors involved in fruit size were investigated through comparative analysis using sports that showed a difference in fruit size from the original variety. ...
... Auxin biosynthesis-related genes MdTAR1 and MdYUCCA6 were proposed as candidate genes underlying the fruit size difference (Bu et al., 2020). Interestingly, the effect of auxin on apple fruit size has been previously reported (Devoghalaere et al., 2012). When exogenous auxin was injected into developing apple fruit, cell expansion was initiated, which led to an increase in cell size. ...
... In strawberry, gibberellins regulate the physiological processes during cell expansion and crosstalk with auxin, playing an important role in cell division and expansion (Csukasi et al., 2011). In apple, auxin level within fruit cortex increased during the cell division phase and decreased until the late cell expansion phase (Devoghalaere et al., 2012). Furthermore, ethylene, abscisic acid, auxin, and gibberellins proteins are up-regulated during the maturation phase (Li et al., 2016a). ...
... GO and WGCNA revealed that genes involving cell division, phytohormone metabolism, and cell wall catabolism were differentially expressed during early fruit Figure S2). Auxin has been shown to be involved in the initial signal for fertilization, cell division, and cell expansion in fruit development (Devoghalaere et al. 2012). Two auxin signaling-related genes, MdSAUR36 and MdILL2, were predicted as candidate genes controlling fruit size in this study. ...
Final fruit size of apple (Malus domestica) cultivars is related to both mesocarp cell division and cell expansion during fruit growth, but it is unclear whether the cell division and/or cell enlargement determine most of the differences in fruit size between Malus species. In this study, by using an interspecific hybrid population between Malus asiatica “Zisai Pearl” and Malus domestica cultivar “Red Fuji,” we found that the mesocarp cell number was the main causal factor of diversity in fruit size between Malus species. Rapid increase in mesocarp cell number occurred prior to 28 days after anthesis (DAA), while cell size increased gradually after 28 DAA until fruit ripening. Six candidate genes related to auxin signaling or cell cycle were predicted by combining the RNA-seq data and previous QTL data for fruit weight. Two InDels and 10 SNPs in the promoter of a small auxin upregulated RNA gene MdSAUR36 in Zisai Pearl led to a lower promoter activity than that of Red Fuji. One non-synonymous SNP G/T at 379 bp downstream of the ATG codon of MdSAUR36, which was heterozygous in Zisai Pearl, exerted significant genotype effects on fruit weight, length, and width. Transgenic apple calli by over-expressing or RNAi MdSAUR36 confirmed that MdSAUR36 participated in the negative regulation of mesocarp cell division and thus apple fruit size. These results could provide new insights in the molecular mechanism of small fruit size in Malus accession and be potentially used in molecular assisted breeding via interspecific hybridization.
... Similarly to Callan and Lombard (1978), we found that pear fruit diameter increased with the presence of seeds ( Figure A.7). This is perhaps due to the release of auxins which in turn cause the cells in pomme fruits to grow larger (Devoghalaere et al., 2012). An increase in fruit size, even if modest, could potentially lead to a greater yield per acre, bolstering the profitability of pear operations. ...
Broadcast spraying of antibiotics in crops is widely used for controlling bacterial plant pathogens. The effects of antibiotics on non-target (and especially beneficial) organisms in cropping systems, however, are not well studied. Pollinators are of particular concern because in pear and apple crops, antibiotics for controlling fire blight (Erwinia amylovora) are sprayed during bloom, likely exposing pollinators. This is especially relevant as laboratory evidence suggests that antibiotics could have sublethal effects on bee foraging behavior and colony health. But to our knowledge these potential impacts have not been studied in field settings. Here, we compared the effects of two fire blight control methods, a single spray of an antibiotic (oxytetracycline) and a biological antagonist (Aureobasidium pullulans), on honey bee (Apis mellifera) foraging, pollination, and fruit set in pear orchards. Complementing these field assessments, we conducted laboratory experiments to examine the effects of these treatments on locomotion and foraging behavior of a bumble bee species, Bombus vosnesenskii. We found that honey bees visited fewer flowers and foraged longer on each flower in orchards sprayed with antibiotics than with a biological product, but there were no differences in crop pollination and seed set. The pear cultivars we worked in, however, can self-pollinate. In the lab, we found that feeding on high doses of either the antibiotic or the biological antagonist reduced bumble bee foraging relative to controls. The limited impact of antibiotics on pear pollination observed in this study suggest that antibiotics pose a low economic risk to pear growers, especially for self-compatible cultivars. Still, crops with higher pollinator dependence may be affected by reductions in bee visitation. Future studies should examine the impacts of multiple antibiotic sprays within a season, which are common during warm springs, and their long-term health impacts on both individual bees and colonies.
... In Brassica napus L., the BnARF18 mutant restricted cell expansion in the cell wall, resulting in a decrease in seed size [21]. Arf106 is expressed during cell division and cell expansion, which is an indirect factor controlling apple fruit size [22]. Ethylene regulation of fruit ripening involves multiple ethylene receptor proteins, transcription factors, and downstream target genes, forming a complex network [23]. ...
Gibberellin (GA) is an important plant hormone that is involved in various physiological processes during plant development. Sweet cherries planted in southern China have always encountered difficulty in bearing fruit. In recent years, gibberellin has successfully solved this problem, but there has also been an increase in malformed fruits. This study mainly explores the mechanism of malformed fruit formation in sweet cherries. By analyzing the synthesis pathway of gibberellin using metabolomics and transcriptomics, the relationship between gibberellin and the formation mechanism of deformed fruit was preliminarily determined. The results showed that the content of GA3 in malformed fruits was significantly higher than in normal fruits. The differentially expressed genes in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were mainly enriched in pathways such as “plant hormone signal transduction”, “diterpenoid biosynthesis”, and “carotenoid biosynthesis”. Using Quantitative Real-Time Reverse Transcription PCR (qRT-PCR) analysis, the gibberellin hydrolase gene GA2ox and gibberellin synthase genes GA20ox and GA3ox were found to be significantly up-regulated. Therefore, we speculate that the formation of malformed fruits in sweet cherries may be related to the accumulation of GA3. This lays the foundation for further research on the mechanism of malformed sweet cherry fruits.
... Since GH3 was reported to catalyze the synthesis of indole-3acetic acid (IAA)-amino acid conjugates, the reduction in GH3 indicated a high level of free IAA concentration [35]. During the early periods of fruit expansion, the transcript of GH3 was at a lower level, according to the high auxin concentration at the same development stage in apples [36]. Hence, GAs may play a role in increasing auxin signaling to regulate the fruit development of R. roxburghii. ...
Gibberellins (GAs) play indispensable roles in the fruit development of horticultural plants. Unfortunately, the molecular basis behind GAs regulating fruit development in R. roxburghii remains obscure. Here, GA3 spraying to R. roxburghii ‘Guinong 5’ at full-bloom promoted fruit size and weight, prickle development, seed abortion, ascorbic acid accumulation, and reduction in total soluble sugar. RNA-Seq analysis was conducted to generate 45.75 Gb clean reads from GA3- and non-treated fruits at 120 days after pollination. We obtained 4275 unigenes belonging to differently expressed genes (DEGs). Gene ontology and the Kyoto Encyclopedia of Genes and Genomes displayed that carbon metabolism and oxidative phosphorylation were highly enriched. The increased critical genes of DEGs related to pentose phosphate, glycolysis/gluconeogenesis, and citrate cycle pathways might be essential for soluble sugar degradation. Analysis of DEGs implicated in ascorbate revealed the myoinositol pathway required to accumulate ascorbic acid. Finally, DEGs involved in endogenous phytohormones and transcription factors, including R2R3 MYB, bHLH, and WRKY, were determined. These findings indicated that GA3-trigged morphological alterations might be related to the primary metabolites, hormone signaling, and transcription factors, providing potential candidate genes that could be guided to enhance the fruit development of R. roxburghii in practical approaches.
