Search

Fatty acids in avocado fruit are crucial components influencing taste as well as fruit quality and nutritional value. Changes to fatty acid contents and concentrations in avocado fruit are important because of the associated effects on sensory properties. Hence, plant physiologists and molecular biologists interested in elucidating the influence of transcription factors on fatty acid accumulation in avocado fruit. In this study, APETALA2/ethylene-responsive factor (AP2/ERF) family members in avocado (Persea americana Mill.) were systematically and comprehensively analyze to identify potential PaAP2/ERF genes related to fatty acid accumulation. The results of bioinformatics analysis and the expression profiles of the AP2/ERF members suggested that 10 highly expressed PaAP2/ERF genes may encode transcription factors with functions related to the fatty acid accumulation in the avocado mesocarp. Furthermore, PaWRI1 and PaWRI2 , two AP2/ERF transcription factor genes in avocado, were functionally characterized regarding their effects on fatty acid accumulation. The transcriptome and biochemical analyses of PaWRI1-2 -overexpressing transgenic tomato plants revealed the up-regulated expression of 17 unigenes related to fatty acid synthesis and triacylglycerol assembly as well as increased fatty acid contents relative to the corresponding levels in the wild-type plants. In contrast, the overexpression of PaWRI2 in transgenic tomato plants up-regulated the expression of only six unigenes associated with fatty acid synthesis and triacylglycerol assembly and negligibly affected fatty acid accumulation when compared with wild-type plants. This systematic analysis provides a foundation for future studies regarding AP2/ERF functions associated with fatty acid accumulation. • Excavating ten potential AP2/ERF gene candidates related to fatty acid accumulation. • AP2/ERF genes PaWRI2 do not enhance fatty acid accumulation in transgenic tomato. [ABSTRACT FROM AUTHOR]

Mango is an important tropical fruit in the world. Mango anthracnose is one of the most severe postharvest diseases caused by Colletotrichum gloeosporioides. Biocontrol by actinomycetes is considered as a promising strategy. Here, 67 actinomycetes were isolated from mangrove forest soils. A strain labelled with HSL-9B showed 63.21% of the inhibition ratio against C. gloeosporioides and broad-spectrum antifungal activities against the selected seven postharvest pathogens. The strain was assigned to Streptomyces malaysiensis based on the phenotypic, biochemical and whole-genomic profiles. Strain HSL-9B extracts significantly reduced the disease severity of mango anthracnose in vivo. 8 × EC 50 of extracts completely inhibited the infection of pathogen during the entire storage process. Total soluble sugar contents on harvested mangoes were effectively kept. 4 × EC 50 of extracts obviously inhibited spore germination and mycelial growth of C. gloeosporioides , resulting in mycelial rupture and cell ultrastructure destroying. The biosynthesis gene clusters (BGC) of secondary metabolites involved in antagonism were identified by compared with the whole-genome sequencing of strain HSL-9B. Fifteen compounds in strain HSL-9B extracts were obtained using the gas chromatography-mass spectrometry (GC-MS). 12-methyl-tridecanoic acid was one of dominant compounds identified in extracts. Hence, S. malaysiensis HSL-9B is an important bioresource for exploring novel natural products to manage postharvest disease. • Streptomyces strain with strong antifungal activities was isolated and identified. • Strain HSL-9B inhibited mango decay and maintained its quality during postharvest. • Extracts damaged the cell integrity and inhibited spore germination of pathogen. • Biosynthetic gene clusters were found in the sequencing genome of strain HSL-9B. • Several secondary metabolites were identified in strain HSL-9B extracts. [ABSTRACT FROM AUTHOR]

• A new isolated marine Streptomyces sp. H4 with strong antifungal ability against C. fragariae. • Strain H4 extracts obviously inhibiting expansion of C. fragariae on strawberry fruit. • Strain H4 extracts significantly maintaining better fruit quality of strawberry. • Strain H4 extracts inhibiting spore germination and causing cell collapse of pathogen. • Strain H4 exhibiting a broad-spectrum antifungal activity. Anthracnose is a fungal disease caused by Colletotrichum species, which is detrimental to numerous fruits, including strawberry. Use of fungicides to maintain fruit quality leads to potential environmental pollution and health risk. Biocontrol using beneficial microorganisms such as Streptomyces has been applied successfully for controlling postharvest diseases of fruit. In this study, strain H4 with a high antifungal activity against C. fragariae was isolated from Dichotella gemmacea in Xisha islands of South China Sea. Combining the morphological and biochemical characteristics with the 16S rRNA sequence analysis, this strain was assigned as Streptomyces sp. A preventive treatment using strain H4 extracts significantly reduced severity and incidence of anthracnose disease and maintained fruit hardness and color on harvested strawberry fruits. A minimum inhibitory concentration (MIC) and a minimum fungicidal concentration (MFC) were 1.563 × 10−3 g L-1 and 3.125 × 10−3 g L-1, respectively. Extracts could effectively inhibit mycelial growth and spore germination of C. fragariae in vitro. The mycelial structure of pathogenic fungi showed deformation, shrinkage, collapse and tortuosity. A significant decrease in sugar and protein contents was also observed in treated C. fragariae mycelia. Fourteen chemical compounds were identified by gas chromatography-mass spectrometer (GC–MS). Dibutyl phthalate was the major constituent. Notably, strain H4 and its extracts exhibited a broad-spectrum antifungal activity against seven selected plant pathogenic fungi. Hence, Streptomyces sp. H4 and its metabolites have a high efficiency of antagonistic roles against phytopathogenic fungi diseases. It provides a promising biological agent to control anthracnose of strawberry fruit. [ABSTRACT FROM AUTHOR]

• A cellulolytic Acetobacter orientalis XJC-C was identified from a soft coral. • Strain XJC-C has a strong resistance to high salt and temperature. • Strain XJC-C enhances the composting efficiency of banana residues. • Strain XJC-C improves functional diversity of microbial community during composting. • Strain YS-26 enhances metabolism capacity of carboxylic acids and carbohydrates. Banana residues are an important energy resource after fruit harvesting. The optionally dumping and burning causes severely environmental problems. Traditional compost efficiency was limited by lignocellulosic composition of banana residues. Inoculation with cellulase-producing microbes provides an efficient strategy for improving degradation of lignocellulosic materials. In our study, a newly isolated cellulolytic bacterium Acetobacter orientalis XJC-C with a salt and high temperature resistance was identified from a marine soft coral. By contrast, the strain can biodegrade different lignocellulosic agricultural residues, especially banana straw. The highest cellulolytic and ligninolytic enzyme activities were detected during composting at 40 days. Compared with the negative and positive control groups, the lignin degradation rate reached 76.24% in the A. orientalis XJC-C group, increased by 47.08% and 21.85%, respectively. Moreover, the strain improved significantly the metabolic activity and functional diversity of bacterial community. Hence, A. orientalis XJC-C will be a promising candidate for degrading lignocellulosic agricultural residues. [ABSTRACT FROM AUTHOR]

• A cellulolytic bacterium Fictibacillus sp. was identified from a soft coral. • Strain YS-26 degrades various agro-residues by producing different cellulases. • Strain YS-26 enhances carboxylic acids and polymers metabolism capacity. • Strain YS-26 improves the functional diversity of soil microbial community. A new isolated cellulolytic bacterium from a soft coral was named as Fictibacillus sp YS-26 based on the morphologic and molecular characteristics. It can degrade different lignocellulosic agricultural residues by producing cellulolytic enzymes, α -amylase, protease, pectinase and xylanase. Especially, Fictibacillus sp. YS-26 exhibited the highest cellulolytic activities in the soybean meal medium. By contrast, the fermentation broth of Fictibacillus sp. YS-26 significantly enhanced utilization efficiency of carboxylic acids and polymers by soil microorganisms as well as the microbial metabolism function and community diversity in rhizosphere soil of banana plantlets. The fermentation broth also improved soil characters and increased the growth of banana plantlets. We found that soil total nitrogen and electrical conductivity had a positive relationship with the increase of microbial diversity. Hence, Fictibacillus sp. YS-26 will be a promising candidate for biodegradating lignocellulosic biomass and improving the soil microbial diversity. [ABSTRACT FROM AUTHOR]