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The ripening process of Chinese bayberries (Myrica rubra) is intricate, involving a multitude of molecular interactions. Here, we integrated transcriptomic and metabolomic analysis across three developmental stages of the Myrica rubra (M. rubra) to elucidate these processes. A differential gene expression analysis categorized the genes into four distinct groups based on their expression patterns. Gene ontology and pathway analyses highlighted processes such as cellular and metabolic processes, including protein and sucrose metabolism. A metabolomic analysis revealed significant variations in metabolite profiles, underscoring the dynamic interplay between genes and metabolites during ripening. Flavonoid biosynthesis and starch and sucrose metabolism were identified as key pathways, with specific genes and metabolites playing crucial roles. Our findings provide insights into the molecular mechanisms governing fruit ripening in M. rubra and offer potential targets for breeding strategies aimed at enhancing fruit quality. [ABSTRACT FROM AUTHOR]

Fruit development and softening play pivotal roles in determining fruit quality and post-harvest shelf life in Chinese bayberry (Myrica rubra). However, the specific role of beta (β)-galactosidase, particularly β-galactosidase of M. rubra (MrBGAL), in facilitating fruit softening remains unclear. In this study, we aimed to address this gap by investigating the involvement of MrBGALs genes in fruit softening. We identified all 15 MrBGALs and conducted a comprehensive analysis, including phylogenetic relationships, gene structure, protein motifs, co-linearity, and expression patterns. Using phylogenetic analysis, we classified all MrBGALs into five distinct groups. Additionally, cis-element prediction and comparative genome analysis provided insightful clues about the functionality of MrBGALs. Transcriptome data revealed unique expression patterns of MrBGALs throughout various fruit development stages. These findings introduce valuable candidate genes that can contribute to unraveling the functions and molecular mechanisms governing fruit development and softening in Chinese bayberry. [ABSTRACT FROM AUTHOR]

Twig blight disease is the primary disease that affects the production of Myrica rubra in China. It was reported that exogenous brassinolide (BL) can improve disease resistance in plants. Here, we examined the effects of exogenous BL on disease resistance, chlorophyll contents, antioxidant enzyme activity, ROS accumulation, and key gene expression of M. rubra to analyze the mechanism of BR-induced resistance of twig blight disease in M. rubra. The results demonstrated that 2.0 mg·L−1 of BL could significantly lessen the severity of twig blight disease in M. rubra. Exogenous BL increased the contents of chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll. Moreover, exogenous BL also significantly enhanced the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and decreased malondialdehyde (MDA) content and reactive oxygen species (ROS) accumulation in leaves, such as H2O2 and O2·−. Additionally, exogenous BL dramatically up-regulated the expression of pathogenesis-related (PR) genes such as MrPR1, MrPR2, and MrPR10, as well as important genes such as MrBAK1, MrBRI1, and MrBZR1 involved in brassinosteroid (BR) signaling pathway. The transcriptome analysis revealed that a total of 730 common differentially expressed genes (DEGs) under BL treatment were found, and these DEGs were primarily enriched in four Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Based on these findings, nine important candidate genes related to the resistance of twig blight disease under BL treatment were further identified. In this study, we elucidated the effects of exogenous BL on enhancing the resistance of M. rubra to twig blight disease and preliminary analyzed the potential mechanism of resistance induction, which will provide a crucial foundation for the management and prevention of twig blight disease in M. rubra. [ABSTRACT FROM AUTHOR]

As a subtropical and tropical tree, bayberry (Myrica rubra) is an important fruit tree grown commercially in southern China. Interestingly, our studies found that the fruit quality of bayberry with accompanying ryegrass was significantly improved, but its mechanism remains unclear. The aim of this study was to explore the mechanism of accompanying ryegrass on the beneficial effect of the fruit quality of bayberry by measuring the vegetative growth parameters, fruit parameters with economic impact, physical and chemical properties of rhizosphere soil, microbial community structure, and metabolites of the bayberry with/without ryegrass. Notably, the results revealed a significant difference between bayberry trees with and without accompanying ryegrass in fruit quality parameters, soil physical and chemical properties, microbial community structure, and metabolites. Compared with the control without accompanying ryegrass, the planting of ryegrass increased the titratable sugar, vitamin C, and titratable flavonoid contents of bayberry fruits by 2.26%, 28.45%, and 25.00%, respectively, and decreased the titratable acid contents by 9.04%. Furthermore, based on 16S and ITS amplicon sequencing of soil microflora, the accompanying ryegrass caused a 12.47% increment in Acidobacteriota while a 30.04% reduction in Actinobacteria was recorded, respectively, when compared with the bayberry trees without ryegrass. Redundancy discriminant analysis of microbial communities and soil properties indicated that the main variables of the bacterial community included available nitrogen, available phosphorus, exchangeable aluminum, and available kalium, while the main variables of the fungal community included exchangeable aluminum, available phosphorus, available kalium, and pH. In addition, the change in microbial community structure was justified by the high correlation analysis between microorganisms and secondary metabolites. Indeed, GC-MS metabolomics analysis showed that planting ryegrass caused a 3.83%–144.36% increase in 19 metabolites such as 1,3-Dipentyl-heptabarbital and carbonic acid 1, respectively, and a 23.78%–51.79% reduction of 5 metabolites compared to the bayberry trees without the accompanying ryegrass. Overall, the results revealed the significant change caused by the planting of ryegrass in the physical and chemical properties, microbiota, and secondary metabolites of the bayberry rhizosphere soils, which provides a new insight for the ecological improvement of bayberry. [ABSTRACT FROM AUTHOR]

Microbial compost plays a crucial role in improving soil health, soil fertility, and plant biomass. These biofertilizers, based on microorganisms, offer numerous benefits such as enhanced nutrient acquisition (N, P, and K), production of hydrogen cyanide (HCN), and control of pathogens through induced systematic resistance. Additionally, they promote the production of phytohormones, siderophore, vitamins, protective enzymes, and antibiotics, further contributing to soil sustainability and optimal agricultural productivity. The escalating generation of organic waste from farm operations poses significant threats to the environment and soil fertility. Simultaneously, the excessive utilization of chemical fertilizers to achieve high crop yields results in detrimental impacts on soil structure and fertility. To address these challenges, a sustainable agriculture system that ensures enhanced soil fertility and minimal ecological impact is imperative. Microbial composts, developed by incorporating characterized plant-growth-promoting bacteria or fungal strains into compost derived from agricultural waste, offer a promising solution. These biofertilizers, with selected microbial strains capable of thriving in compost, offer an eco-friendly, cost-effective, and sustainable alternative for agricultural practices. In this review article, we explore the potential of microbial composts as a viable strategy for improving plant growth and environmental safety. By harnessing the benefits of microorganisms in compost, we can pave the way for sustainable agriculture and foster a healthier relationship between soil, plants, and the environment. [ABSTRACT FROM AUTHOR]

Bayberry twig blight caused by the ascomycete fungus Pestalotiopsis versicolor is a devastating disease threatening worldwide bayberry production. However, the molecular basis underlying the pathogenesis of P. versicolor is largely unknown. Here, we identified and functionally characterized the MAP kinase PvMk1 in P. versicolor through genetic and cellular biochemical approaches. Our analysis reveals a central role of PvMk1 in regulating P. versicolor virulence on bayberry. We demonstrate that PvMk1 is involved in hyphal development, conidiation, melanin biosynthesis, and cell wall stress responses. Notably, PvMk1 regulates P. versicolor autophagy and is essential for hyphal growth under nitrogen-depleting conditions. These findings suggest the multifaceted role of PvMk1 in regulating P. versicolor development and virulence. More remarkably, this evidence of virulence-involved cellular processes regulated by PvMk1 has paved a fundamental way for further understanding the impact of P. versicolor pathogenesis on bayberry. [ABSTRACT FROM AUTHOR]

In recent years, bayberry decline disease has caused significant damage to the bayberry industry. In order to evaluate whether humic acid can be used to effectively control the disease, this research examined the nutritional growth and fruit quality of bayberry, soil physical and chemical properties, soil microbial community structure, and metabolites. Results indicated that the application of humic acid not only improved the vigor and fruit quality of diseased trees, but also increased the diversity of microbial communities in the rhizosphere soil. A great increase was observed in the relative abundance of bacterial genus Mycobacterium and Crossiella; fungal genus Fusarium and Coniosporium. In contrast, a significant decrease was observed in the relative abundance of bacterial genus Acidothermus, Bryobacter, Acidibacter, fungal genus of Geminibasidium and Mycena. Analysis of redundancies (RDA) for microbial communities and soil characteristics showed that the main four variables, including available nitrogen, phosphorus, potassium, and calcium, had a great effect on the composition of bacterial and fungal communities in bayberry rhizosphere soil at the genus level. The main four variables had a greater effect on bacterial communities than on fungal communities. In addition, ABC transporter, arginine and proline metabolism, galactose metabolism, and glutathione metabolism were significantly affected by humic acid, which changed the content of 81 metabolites including 58 significantly down-regulated metabolites such as isohexonic acid and carinitine, and 23 significantly up-regulated metabolites such as acidic acid, guaninosuccinate, lyxose, 2-monoolein, epicatechin, and pentonolactone. These metabolites also significantly correlated with rhizosphere soil microbiota at the phylum, order, and genus levels. In conclusion, the results demonstrated the role of humic acid on plant growth and fruit quality, as well as rhizosphere soil characteristics, microbiota, and secondary metabolites, which provides novel insights into the control of bayberry decline disease. [ABSTRACT FROM AUTHOR]

Sponge gourd belongs to the Cucurbitaceae family and Luffa genus. It is an economically valuable vegetable crop with medicinal properties. The fruit size of sponge gourd presents distinct diversity; however, the molecular insights of fruit size regulation remain uncharacterized. Therefore, two sponge gourd materials with distinct fruit sizes were selected for a comparative transcriptome analysis. A total of 1390 genes were detected as differentially expressed between long sponge gourd (LSG) and short sponge gourd (SSG) samples, with 885 downregulated and 505 upregulated in SSG compared with LSG. KEGG pathway enrichment analysis revealed that the MAPK signaling pathway, biosynthesis of secondary metabolites, and plant hormone signal transduction were significantly enriched. The DEGs involved in the cell cycle and cell division, plant hormone metabolism, and MAPK signal transduction were crucial for sponge gourd fruit size regulation. Additionally, the transcription factor families of ERF, NAC, bHLH, MYB, WRKY, and MADS-box were associated with fruit size regulation. The qRT-PCR validation for selected DEGs were generally consistent with the RNA-Seq results. These results obtained the candidate genes and pathways associated with fruit size and lay the foundation for revealing the molecular mechanisms of fruit size regulation in sponge gourd. [ABSTRACT FROM AUTHOR]

Decline disease causes serious damage to bayberry, but the reasons behind this disease are not completely understood, although fungal pathogenicity factors have been proposed. Our past studies have identified that the adversity of this disease is linked to the application of soil fungicide. The objective of this study is to explore the mechanism and alleviation effect of the use of the fungicide prochloraz in this disease by investigating the plant and soil parameters. The results of the current study reveal that the application of prochloraz could improve the tree vigor and fruit quality of decline-diseased bayberry. The beneficial effect of prochloraz on plant growth and fruit quality may be associated with its influence on the rhizosphere soil properties and soil microbiota. Indeed, the application of prochloraz was shown to significantly affect the relative abundance and diversity of the rhizosphere soil microbiota, with it having a greater effect on bacteria than on fungi. Furthermore, the community composition of rhizosphere soil bacteria and fungi at the genus level was found to be significantly affected by the pH, available phosphorus, alkali-hydrolyzable nitrogen, and exchangeable magnesium, which exhibited a greater effect on bacteria than on fungi. In addition, prochloraz significantly affected the metabolic pathways of pyrimidine, galactose, butanoate, arginine, and proline and changed the contents of 58 metabolites, with an 18.59–149.48% increase seen in 51 metabolites and a 31.52–95.21% reduction seen in 7 metabolites. Interestingly, these metabolites were found to be significantly correlated with the rhizosphere soil microbiota at the levels of phylum, order, and genus. Overall, the results of this study provide an alternative choice for protecting bayberry from the damage caused by decline disease. [ABSTRACT FROM AUTHOR]

Decline disease causes severe damage to bayberry. However, the cause of this disease remains unclear. Interestingly, our previous studies found that the disease severity is related with the level of soil fertilizer. This study aims to explore the effect and mechanism of compound fertilizer (CF) and bio-organic fertilizer (OF) in this disease by investigating the vegetative growth, fruit characters, soil property, rhizosphere microflora and metabolites. Results indicated that compared with the disease control, CF and OF exhibited differential effect in plant healthy and soil quality, together with the increase in relative abundance of Burkholderia and Mortierella, and the reduction in that of Rhizomicrobium and Acidibacter, Trichoderma, and Cladophialophora reduced. The relative abundance of Geminibasidium were increased by CF (251.79%) but reduced by OF (13.99%). In general, the composition of bacterial and fungal communities in rhizosphere soil was affected significantly at genus level by exchangeable calcium, available phosphorus, and exchangeable magnesium, while the former two variables had a greater influence in bacterial communities than fungal communities. Analysis of GC-MS metabonomics indicated that compared to the disease control, CF and OF significantly changed the contents of 31 and 45 metabolites, respectively, while both fertilizers changed C5-branched dibasic acid, galactose, and pyrimidine metabolic pathway. Furthermore, a significant correlation was observed at the phylum, order and genus levels between microbial groups and secondary metabolites of bayberry rhizosphere soil. In summary, the results provide a new way for rejuvenation of this diseased bayberry trees. [ABSTRACT FROM AUTHOR]

Decline disease causes serious damage and rapid death in bayberry, an important fruit tree in south China, but the cause of this disease remains unclear. The aim of this study was to investigate soil quality, microbial community structure and metabolites of rhizosphere soil samples from healthy and diseased trees. The results revealed a significant difference between healthy and diseased bayberry in soil properties, microbial community structure and metabolites. Indeed, the decline disease caused a 78.24% and 78.98% increase in Rhizomicrobium and Cladophialophora, but a 28.60%, 57.18%, 38.84% and 68.25% reduction in Acidothermus, Mortierella, Trichoderma and Geminibasidium, respectively, compared with healthy trees, based on 16S and ITS amplicon sequencing of soil microflora. Furthermore, redundancy discriminant analysis of microbial communities and soil properties indicated that the main variables of bacterial and fungal communities included pH, organic matter, magnesium, available phosphorus, nitrogen and calcium, which exhibited a greater influence in bacterial communities than in fungal communities. In addition, there was a high correlation between the changes in microbial community structure and secondary metabolites. Indeed, GC–MS metabolomics analysis showed that the healthy and diseased samples differed over six metabolic pathways, including thiamine metabolism, phenylalanine–tyrosine–tryptophan biosynthesis, valine–leucine–isoleucine biosynthesis, phenylalanine metabolism, fatty acid biosynthesis and fatty acid metabolism, where the diseased samples showed a 234.67% and 1007.80% increase in palatinitol and cytidine, respectively, and a 17.37–8.74% reduction in the other 40 metabolites compared to the healthy samples. Overall, these results revealed significant changes caused by decline disease in the chemical properties, microbiota and secondary metabolites of the rhizosphere soils, which provide new insights for understanding the cause of this bayberry disease. [ABSTRACT FROM AUTHOR]

Bayberry is an important fruit tree native to the subtropical regions of China. However, a systematic twig blight disease caused by Pestalotiopsis versicolor and P. microspora, resulted in the death of the whole tree of bayberry. The main variety Dongkui is highly sensitive to the twig blight disease, but the variety Zaojia is very highly resistant to the disease. Therefore, it is very necessary to clear the difference between resistant and susceptible varieties in response to the fungal infection. In this paper, we investigated the response of resistant and susceptible bayberry cultivars to infection of twig blight pathogen by histological observation and gibberellin signaling pathway-related genes expression. Microscopic observation revealed the difference in the infection process between resistant and susceptible varieties. The results of frozen scanning electron microscopy showed that the Pestalotiopsis conidia were shrunk, the mycelium was shriveled and did not extend into the cells of resistant cultivars, while the conidia were full and the top was extended, the mycelia was normal and continued to extend to the cells of a susceptible cultivar. Indeed, the medulla cells were almost intact in resistant cultivar, but obviously damaged in susceptible cultivar after inoculation of the main fungal pathogen P. versicolor conidia, which is earlier germinated on sterile glass slide than that of a hard plastic slide. The quantitative real-time PCR results showed a significant difference between resistant and susceptible cultivars in the expression of gibberellin signaling pathway-related genes in leaves and stems of bayberry, which is closely related to infection time, the type of genes and varieties. Overall, this study provides a clue for our understanding of the resistance mechanism of bayberry against the twig blight disease. [ABSTRACT FROM AUTHOR]

Bayberry is an attractive, nutritious, and popular fruit in China. The plant fungal pathogen Pestalotiopsis versicolor XJ27 is the causative agent of bayberry twig blight disease, which severely affects bayberry production. Traditional control techniques, such as chemical fungicides, are being used to control this disease; however, these techniques cause environmental and health hazards. In this study, we screened sweet potato rhizospheric bacteria with biocontrol potentials against P. versicolor XJ27, the bayberry twig blight pathogen. Ten isolates showed inhibition; Bacillus siamensis S3 and Bacillus tequilensis S5 showed the highest fungal growth inhibition. The antagonistic bacterial culture suspensions of S3 and S5 inhibited the mycelial growth by 82.9% and 76.2%, respectively. Their extracellular culture filtrates had mycelial growth inhibition of 86.8% and 82.2%, respectively. In detached leaf assay, the extracellular culture filtrates of S3 and S5 inhibited the size of the leaf lesion by 82.3% and 76.2%, respectively. SEM and TEM imaging showed a severe hyphal-damaged structure caused by the antagonistic bacteria. The fungal inhibition mechanisms might employ the hydrolytic enzymes and lipopeptides produced by the bacteria. Both the S3 and S5 have chitinase and protease activity; they produce a series of lipopeptides such as surfactin, iturin, and mycosubtilin. Therefore, we can suggest these bacteria as biocontrol agents for bayberry twig blight disease as an alternative to fungicides based upon their attributes of antifungal activity. [ABSTRACT FROM AUTHOR]