Virus-Induced Gene Silencing of the Eggplant Chalcone Synthase Gene during Fruit Ripening Modifies Epidermal Cells and Gravitropism

Zeng

et al. 2020

BMC Genomics

Background: Anthocyanins are common substances with many agro-food industrial applications. However, anthocyanins are generally considered to be found only in natural plants. Our previous study isolated and purified the fungus Aspergillus sydowii H-1, which can produce purple pigments during fermentation. To understand the characteristics of this strain, a transcriptomic and metabolomic comparative analysis was performed with A. sydowii H-1 from the second and eighth days of fermentation, which confer different pigment production. Results: We found five anthocyanins with remarkably different production in A. sydowii H-1 on the eighth day of fermentation compared to the second day of fermentation. LC-MS/MS combined with other characteristics of anthocyanins suggested that the purple pigment contained anthocyanins. A total of 28 transcripts related to the anthocyanin biosynthesis pathway was identified in A. sydowii H-1, and almost all of the identified genes displayed high correlations with the metabolome. Among them, the chalcone synthase gene (CHS) and cinnamate-4hydroxylase gene (C4H) were only found using the de novo assembly method. Interestingly, the best hits of these two genes belonged to plant species. Finally, we also identified 530 lncRNAs in our datasets, and among them, three lncRNAs targeted the genes related to anthocyanin biosynthesis via cis-regulation, which provided clues for understanding the underlying mechanism of anthocyanin production in fungi. Conclusion: We first reported that anthocyanin can be produced in fungus, A. sydowii H-1. Totally, 31 candidate transcripts were identified involved in anthocyanin biosynthesis, in which CHS and C4H, known as the key genes in anthocyanin biosynthesis, were only found in strain H1, which indicated that these two genes may contribute to anthocyanins producing in H-1. This discovery expanded our knowledges of the biosynthesis of anthocyanins and provided a direction for the production of anthocyanin.

Section: Discussionmentioning

confidence: 99%

Identification of a novel anthocyanin synthesis pathway in the fungus Aspergillus sydowii H-1

Zeng

et al. 2020

BMC Genomics

“…VIGS is a reverse-genetics method based on RNA-mediated antiviral plant defense that has been used to rapidly identify gene function in plants [25]. The e ciency of VIGS in inducing endogenous gene silencing is related to multiple factors, such as the correct viral vectors, the characteristics of the target gene, the infection buffer, the activity of Agrobacterium in the bacterial suspension, and the plant growth environment suitable for silencing [26].…”

Section: Discussionmentioning

confidence: 99%

Optimization of a virus-induced gene silencing system and functional elucidation of MaBAM9b in postharvest banana fruits

liu

et al. 2020

Preprint

Abstract Background: The genetic basis of metabolic pathways that operate during fruit ripening needs to be understood before the nutritional value of the banana can be improved. The banana is a typical starch conversion fruit, and β-amylase is a key enzyme that may play an important role in starch degradation during the ripening process. Musa acuminata β-amylase 9b (MaBAM9b) is closely related to starch degradation. However, its exact function in starch degradation has not been demonstrated in banana. Stable genetic transformation to identify gene function is time- and energy-consuming. Thus, an efficient and rapid method is needed for functional identification. Virus-induced gene silencing (VIGS) is a reverse-genetics method based on RNA-mediated antiviral plant defense that has been used to rapidly identify gene functions in plants. The aim of this study is to optimize a VIGS system and functional elucidation of MaBAM9b in postharvest banana fruits. Results: Using 0.5% iodine-potassium-iodide (I2-KI) staining for 150 s, we found that 1:3 TRV1:TRV2-MaBAM9b cultivated at 30 mmHg for 30 s to an optical density (OD) of 0.8 at 600 nm, and kept on Murashige & Skoog (MS) media for 5 days produced the best silencing results. Under these conditions, the total starch content was greatly increased, whereas the β-amylase activity, soluble sugar content, and expression of endogenous MaBAM9b greatly decreased. Conclusions: The system described here is particularly useful for studying genes and networks involved in starch conversion in fruit, which alone would not produce a visual phenotype. This system will provide a platform for functional genomics and fruit quality improvement in the banana.

“…It is thus necessary that an e cient means for rapid functional identi cation is developed. VIGS is a reverse-genetics method based on RNA-mediated antiviral plant defense that has been used to rapidly identify gene function in plants [25]. The e ciency of VIGS in inducing endogenous gene silencing is related to multiple factors, such as the correct viral vectors, the characteristics of the target gene, the infection buffer, the activity of Agrobacterium in the bacterial suspension, and the plant growth environment suitable for silencing [26].…”

Section: Discussionmentioning

confidence: 99%

Optimization of a virus-induced gene silencing system and functional elucidation of MaBAM9b in postharvest banana fruits

liu

et al. 2020

Preprint

Background: Banana is a typical starch conversion fruit, and fruit ripening involves a process of fruit quality formation. To improve the nutritional value of banana, it is necessary to understand the genetic basis of the metabolic pathways that operate during fruit ripening processes. MaBAM9b is a key enzyme gene that might play an important role in starch degradation during the banana fruit ripening process. The identification of gene function by stable genetic transformation is time- and energy-consuming. Thus, developing an efficient and rapid method for functional identification is imperative. Virus-Induced Gene Silencing (VIGS) is a reverse-genetics method based on RNA-mediated antiviral plant defense that has been used to rapidly identify gene function in plants. Results: In this report, 0.5% iodine-potassium-iodide (I2-KI) staining for 150 s determined that a 1:3 ratio of TRV1: TRV2-MaBAM9b cultivated at an optical density of 600 nm (OD600) 0.8 at 30 mmHg for 30 sec and kept on Murashige & Skoog (MS) media for 5 d produced the best silencing results. Under these conditions, the total starch content was greatly increased, while the β-amylase activity, soluble sugar contents, and the expression of endogenous MaBAM9b were greatly decreased. Conclusions: The developed system is particularly useful for studying genes and networks for starch conversion in fruit, which alone would not produce a visual phenotype. This system will provide a platform for banana functional genomics and for banana fruit quality improvement.