Nano-selenium strengthens potato resistance to potato scab induced by Streptomyces spp., increases yield, and elevates tuber quality by influencing rhizosphere microbiomes

IntroductionThe application of selenium could directly or indirectly modulate the activity of antioxidant enzymes in crops, thereby mitigating the detrimental effects of abiotic and biotic stresses on crop health. However, there are few studies on the effects of nano-selenium fertilizer on potato scab caused by Streptomyces spp., potato yield and tuber quality.MethodsWe aimed to elucidate the impact of nano-selenium fertilizer on potato disease resistance, yield, tuber quality, antioxidant enzyme activity and rhizosphere soil bacterial communities, and to determine the optimal frequency and growth stages of nano-selenium fertilizer spraying.Results and discussionThe application of nano-selenium fertilizer twice during the seedling stage significantly reduced the disease index of potato scab, enhanced potato yield, tuber quality (dry matter, Vitamin C, crude protein, and selenium content), and antioxidant enzyme activity (glutathione peroxidase, peroxidase, polyphenol oxidase, superoxide dismutase, and phenylalanine ammonia lyase). The diversity of the rhizosphere bacterial community of potatoes subjected to selenium fertilizer spraying at the seedling stage increased significantly, and concurrently, the symbiotic network of rhizosphere bacterial microbiome grew more complex. Beneficial microorganisms such as bacteria of the genus Bacillus were enriched in the rhizosphere soil. The current study provided theoretical support for the exploration of a potato selenium-enriched technology system and supplies scientific guidance for the utilization of nano-selenium

Application of isotope ratio mass spectrometry (IRMS) in the geographical determination of selected herbs: a review

Herbs have been consumed for their health benefits for centuries and are still attracting increasingly more attention. Their quality is prone to changes in climatic and geo−chemical conditions. Local cultivation patterns also impact the quality of herbs. Therefore, geographical origin is often regarded as an indicator of quality. However, profit−motivated fraud and adulterations degraded the quality of relevant products, and also destroyed the consumers’ health and trust. Isotope ratio mass spectrometry (IRMS) is particularly useful in verifying the origin of herbs as the isotopic composition of several light elements (C, H, O, N and S) contain information about the geographical locations. Changes in the isotopic composition cannot be identified by other techniques but may be detected using IRMS. In this review, current applications of IRMS in tracing ginseng, saffron, chrysanthemum flos and goji berries were discussed and future development was envisage

Root rot in medicinal plants: a review of extensive research progress

Root rot is a general term for soil-borne diseases that cause the necrosis and decay of underground plant parts. It has a wide host range and occurs in various types of plants, including crops, horticultural crops and medicinal plants. Due to the fact that medicinal plants generally have a long growth cycle and are primarily the root and rhizome herbs. This results in root rot causing more serious damage in medicinal plant cultivation than in other plants. Infected medicinal plants have shrivel or yellowed leaves, rotting rhizomes, and even death of the entire plant, resulting in a sharp decline in yield or even total crop failure, but also seriously reduce the commercial specifications and effective ingredient content of medicinal plants. The pathogens of root rot are complex and diverse, and Fusarium fungi have been reported as the most widespread pathogen. With the expansion of medicinal plant cultivation, root rot has occurred frequently in many medicinal plants such as Araliaceae, Fabaceae, Ranunculaceae, and Solanaceae and other medicinal plants. This article reviews recent research progress on root rot in medicinal plants, covering various aspects such as disease characteristics, occurrence, pathogen species, damage to medicinal plants, disease mechanisms, control measures, and genetic factors. The aim is to provide reference for better control of root rot of medicinal plants

Traditional Chinese medicine residues promote the growth and quality of Salvia miltiorrhiza Bunge by improving soil health under continuous monoculture

Continuous monoculture of crops has resulted in reduced yields and quality, as well as soil deterioration. Although traditional Chinese medicine residues (TCMRs) are known to promote plant growth and soil health, few studies have investigated their effectiveness in continuous monoculture soils. Here, we studied the impact of chemical fertilizers (CF) and four TCMRs with antibacterial activities on the growth of S. miltiorrhiza (a widely used medicinal plant in China), accumulation of active ingredients in plants, and soil health under continuous monoculture conditions. Compared with no fertilizer (CK) and CF, fermented Sophora flavescens radix residue (SFRf) and fermented and unfermented Moutan cortex residue (MCRf and MCRu, respectively) resulted in a reduction of the disease index of root rot, while CF did not. The CF and four TCMR treatments increased the accumulation of nitrogen (N) (42.8-124.6% and 17.0-101.7%), phosphorous (P) (19.8-74.7% and 8.3-27.4%), and potassium (K) (104.1-212.0% and 9.3-51.8%) in shoots and roots compared to CK. The differences in nutrient accumulation between the CF and TCMR treatments were statistically insignificant, excepted for the N accumulation in the roots. All fertilization treatments increased plant biomass compared to CK, with increases of 25.57-89.86% and 2.62-35.28% in shoots and roots, respectively. The SFRf treatment exhibited the most significant enhancement in both shoot and root biomass. CF significantly reduced the accumulation of seven active ingredients in roots by 23.90-78.95% compared to CK, whereas each TCMR increased accumulation of certain active ingredients. The TCMR treatments effectively improved the health of deteriorated soil by enhancing soil physicochemical properties, restoring the balance of the microbial community, recruiting beneficial bacteria, and reducing the relative abundance of the pathogen Fusarium. The SFRf treatment exhibited superior performance in improving soil health than other treatments. Overall, the TCMRs outperformed CF in restoring soil health and promoting the yield and quality of S. miltiorrhiza. These findings offer guidance for improving the health of continuous cropping soil and recycling TCMRs

From Lab to Field: Biofertilizers in the 21st Century

This article belongs to the special issue Horticultural Plant Nutrition, Fertilization, Soil Management[EN] Nowadays, legal regulations and social environmental concerns are converging towards the promotion of more sustainable agriculture based on organic compounds and soil preservation. These trends are fuelling the growth of the biofertilizers, which are beneficial preparations containing microorganisms able to enhance a plant’s ability to uptake essential nutrients. Their production and commercialization encompass a multitude of critical steps deeply reviewed in this manuscript through an exhaustive overview of the key stages, such as microorganism selection, new environmental sources, upscaling to field trials, encapsulation, current application systems and regulatory considerations. However, although the economical expectations are promising, several methodological, environmental, and legal concerns are undermining their advancement. The redefinition of international legal frameworks, their enhancement based on trending technologies, and the fostering of multidisciplinary collaboration across sectors are key players to promote biofertilizers as eco-friendly and cost-effective alternatives to chemical fertilizersSIAna Ibáñez (A.I.) is funded by a “Margarita Salas” modality postdoctoral grant (Reference no.: UP2021-025) through the University of León awarded by the Spanish Ministry of Universities within the Recovery, Transformation and Resilience Plan (Modernization and digitalization of the Educational System), with funding from the European Recovery Instrument European Union-NextGenerationEU

Evaluating tissue localization and pathogenicity determinants of Serratia marcescens in cucurbits, and optimizing mesotunnel systems for organic cucurbit production

Insect-vectored vascular pathogens are among the most notorious bacterial pathogens to cause diseases on cucurbits across the world, collectively causing crop losses worth millions of U.S. dollars. These diseases include bacterial wilt of cucurbits, which is caused by Erwinia tracheiphila (E. F. Smith) Holland and transmitted by striped cucumber beetles (Acalymma vittatum F.) and spotted cucumber beetles (Diabrotica undecimpunctata howardi Barber), and cucurbit yellow vine disease (CYVD), which is caused by Serratia marcescens and vectored by squash bugs (Anasa tritis DeGeer). Management of these diseases is particularly important in organic production systems due to the limited availability and efficacy of organic insecticides and alternative control methods for these insect-bacterial pathogen complexes. Here we evaluated mesotunnels as an alternative control method for insect-vectored bacterial diseases in organic cucurbit production systems. Our study focused on evaluating pollination strategies under mesotunnels in commercial-scale plots, assessing the effectiveness of living mulches as an alternative weed control strategy in mesotunnels, and comparing the economic efficiency of the strategies. In the pollination experiment, we showed that keeping mesotunnels closed for the entire growing season and utilizing purchased bumble bees (Bombus impatiens) for pollination resulted in higher net revenue than either opening the tunnel ends or uncovering the tunnels during bloom. Through our weed control trial, however, we showed that teff (Eragrostis tef) can suppress weeds effectively in the furrows between muskmelon beds under mesotunnels, but that mowing it 3 weeks after transplanting the crop is essential to avoid a yield drag associated with competition between this vigorous living mulch and muskmelon. Although landscape fabric effectively eliminated weeds in the furrows and resulted in the highest net returns, it required considerable labor to install and remove. Further, in this work we developed and validated a robust bioassay for S. marcescens that yielded consistent and quantifiable CYVD symptoms on squash in the lab. Here we highlight that mimicking the natural process of S. marcescens transmission by squash bug feeding through injection produced robust and quantifiable CYVD symptoms and that this was not achieved using a mechanical wounding method. We investigated the localization of S. marcescens in cucurbit tissue using microscopy and demonstrated that, as a pathogen causing CYVD on cucurbit crops, S. marcescens localizes to the intercellular spaces in the phloem tissue but does not accumulate in the sieve tubes. Our work has shown that fimbriae contribute to virulence in S. marcescens but are not required for pathogenicity, and that fimbriae play a negative role in biofilm formation in S. marcescens CYVD strains in vitro, suggesting they may do the same in planta. Finally, we demonstrated that both striped and spotted cucumber beetles can harbor and transmit S. marcescens in cucurbits. To our knowledge, this is the first report of cucumber beetles vectoring S. marcescens. Our results show the versatility of S. marcescens in adapting to colonizing different hosts, making it one of only a few pathogens with such attributes. These studies have highlighted the distinct etiology of S. marcescens CYVD strains, illustrating how much we do not yet know of this pathogen

National Program 306: Product Quality and New Uses -- Accomplishment Report, 2018-2022

To ensure the economic viability and competitiveness of U.S. agriculture, it is important that the quality and utilization of harvested agricultural commodities be maintained or enhanced. The U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS) recognizes this and established the National Program (NP 306) Product Quality and New Uses, including biorefining, as the research link between farmers' fields and use by the consumer. The goal of NP 306 is to enhance economic viability and competitiveness of U.S. agriculture by improving quality and marketability of harvested agricultural commodities to meet consumer needs, develop environmentally friendly, efficient processing concepts, and expand domestic and global market opportunities by developing value-added food and non-food technologies and products, as well as expanding biorefining technologies, byproducts, and green fuels