Broccoli Seedlings Research Articles

Organic Nitrogen Nutrition Does Not Increase Glucosinolate Concentrations in Broccoli (Brassica oleracea L. var. italica)

Concentrations of specific secondary metabolites can be higher in organically grown crops. This may be linked to organic nitrogen (N) nutrition that provides a gradual supply of N to crops over the growing season. This study examined whether organic N nutrition influenced the concentration of glucosinolates in broccoli crops. Nitrogen release patterns were determined from three synthetic (Rustica, 12% N; calcium nitrate, 15.5% N; urea, 46% N) and two organic fertilizers in an incubation experiment. Broccoli seedlings were then grown in two N dose response pot trials with different N source or application timing treatments to investigate growth and glucosinolate responses. Synthetic fertilizers released 84 to 89% of total N after 28 days, while chicken manure pellets and composted cow manure had only released 52% and 13% of total N, respectively, after 91 days. Broccoli yield and N content were generally higher in synthetic fertilizer treatments. Glucosinolate concentrations were generally higher in the synthetic fertilizer treatments, and only sinigrin and glucoiberin concentrations in the 800 kg ha−1 N application rate of organic fertilizer matched those in the corresponding synthetic fertilizer treatment. Broccoli head weight was reduced when N was applied fortnightly compared to basal and weekly N applications, but glucosinolate concentrations were not significantly different. Overall, there was no evidence that organic (chicken manure) N nutrition, or the rate of N supply to broccoli plants, affect glucosinolate concentrations.

First Report of Xanthomonas campestris pv. raphani Causing Leaf Spot Disease on Broccoli in China.

Broccoli (Brassica oleracea L. var. italica) is one of the important cruciferous vegetables in China, known for its considerable economic and nutritional value (Li et al. 2021). In September 2023, leaf spot disease was observed on broccoli seedlings in the commercial fields in Weifang City, Shandong Province, China (119°15'E, 36°70'N). Further investigation revealed that the disease incidence was approximately 60% in 4.5 square hectometers (hm2) broccoli field, resulting in substantial economic losses. This disease primarily affects the leaves, manifesting distinct symptoms such as circular, dark necrotic spots that gradually lighten and are encircled by a chlorotic halo. Some lesions further develop a black or purplish border, exhibit concentric zonation, and eventually fall off, leaving behind holes, as shown in Figure S1B and C. In severe cases, decay originates from the central perforation and spreads outwards, as shown in Figure S1A. To identify the causal agent of this disease, infected leaf tissues were collected and surface disinfected by immersing in 75% ethanol for 30 seconds, followed by three rinses with sterile water. The samples were grinded in sterile deionized water, and the extract was plated on NA. After incubation at 28°C for 48 h, individual colonies were transferred to fresh NA plates. A total of 12 strains with the similar morphological characteristics were isolated from diseased samples collected from the three plots. After 48 hours of growth on NA medium at 28℃, each colony attained a diameter ranging from 3 to 5 mm. These colonies appeared yellow, slightly elevated, nearly circular in shape, with a smooth and moist edge. Three representative strains were selected for further investigation. All strains were Gram-negative, aerobic, and rod-shaped. The analysis of BIOLOG GENIII microplate system revealed the capability of three isolates using cellobiose, trehalose, glucose, mannose, galactose, and sucrose. Furthermore, the isolates were unable to hydrolyze arginine and utilize rhamnose and inositol. The 16S rRNA gene was amplified and sequenced to confirm that three isolated bacteria belong to the genus Xanthomonas (OR772321-OR772323), followed by PCR amplification for 4 housekeeping genes atpD, dnaK, gyrB, and rpoD (Young et al. 2008; Saux et al. 2015). The obtained sequences were submitted to the GenBank under accessions OR789628-OR789630, OR785471-OR785473, OR789631-OR789633, and OR785468-OR785470. Gene sequences were aligned, concatenated, and used to generate a phylogenetic tree using the neighbor-joining method in MEGA11 (Tamura et al. 2021). The phylogenetic analysis revealed that all the three isolates were clustered with Xanthomonas campestris pv. raphani strains 5055 and 576, respectively (Figure S2). (Dubrow et al. 2022). These results were consistent with those of the reported X. campestris pv. raphanin (Cruz et al. 2015). To verify the pathogenicity of these strains, we used a spray inoculation method. In detail, bacterial suspensions (30 mL per treatment) containing approximately 108 CFU/ml were sprayed onto healthy, four-week-old broccoli plants and incubated in a phytotron at 28°C and above 90% RH. Negative controls were performed using sterile distilled water. Each isolate underwent three trials and each treatment included 12 broccoli seedlings. Leaf spot symptoms were observed on 5 days post inoculation, as shown in Figure S1E, F and G. Negative control plants showed no symptoms (Figure S1D). We further re-isolated the bacterium from the symptomatic plants and verifying the bacteria as X. campestris pv. raphanin with the aforementioned sequence analysis, thereby fulfilling Koch's postulates. To our knowledge, this is the first report of X. campestris pv. raphani causing leaf spot disease on broccoli in China. This study enhances our understanding of the pathogenic bacterium on broccoli and lays the groundwork for developing targeted management strategies.

Enrichment of broccoli seedlings with iron and its impact on germination, antioxidant activity, and the level of phenolic compounds

Enrichment of broccoli seedlings with iron and its impact on germination, antioxidant activity, and the level of phenolic compounds

Involvement of glucosinolates and phenolics in the promotion of broccoli seedling growth through the modulation of primary and secondary metabolism

Secondary metabolites play an essential role in plant defense. However, the role of glucosinolates and phenols in brassica crop yield in the context of environmentally friendly agricultural practices has not been established. Our study investigated the effects of a Brassica extract, rich in these metabolites, on the physiology and metabolism of broccoli (Brassica oleracea L. var. italica) seedlings and the subsequent development of the plants in adult stages. The results showed an increase in growth in the extract-treated seedlings, which was associated with an alteration of primary and secondary metabolism. In particular, there was an increase in the levels of amino acids, phenolic compounds and hormones, while the levels of glucosinolates decreased. Lipid peroxidation diminished in treated plants, indicating improved membrane integrity. Treated plants subsequently grown in hydroponically showed increased water use efficiency, transpiration, and internal carbon, which contributed to the improved growth of these plants. Overall, our findings underscore the potential of the glucosinolates and phenols ratio as essential to improve crop growth and stress tolerance, as well as revealed the interest of studying the mechanisms involved in the possible uptake and integration of GSLs by broccoli seedlings after external application.

First Report of Pectobacterium polaris Causing Soft Rot on Broccoli in China.

In April 2023, soft rot symptoms were observed in broccoli (Brassica oleracea L. var. italica) commercial fields in Songming County, Yunnan province, China (103°12'E, 25°31'N). The disease incidence in these fields (6 ha in size) was high, exceeding 50%, and it caused significant yield loss. The affected plants displayed characteristic symptoms, with the roots and stems of broccoli becoming soft, yellowish-brown, rotten, and emitting a foul odor. To identify the causal agent, soft rot symptomatic stems were surface sterilized by dipping them in 75% ethanol for 30 seconds, followed by three successive rinses with sterile distilled water. Tissue specimens were then plated onto nutrient agar (NA) plates and incubated at 28°C for 24 hours. (Wang et al. 2022). Three representative bacterial isolates HYC22041801-HYC22041803 from broccoli were selected for further analysis. The colonies on NA plates appeared as white, small, round, and translucent with smooth edges. Physiological and biochemical tests were performed, along with 96 phenotypic screenings using the BIOLOG GENIII microplate system (Biolog, Hayward, CA, USA). Three isolates were negative for D-arabitol, maltose, and sorbitol, but were positive for cellobiose, α-D-glucose, sucrose, glycerol and gentiobiose tests, which are consistent with the reported type strain P. polaris NIBIO1006T (Chen et al. 2021). Total genomic DNA was extracted from three bacterial isolates using the QIAamp DNA Mini Kit (QIAGEN, USA). The 16S rRNA region and nine housekeeping genes (gapA, icdA, mdh, mtlD, pel, pgi, pmrA, proA and rpoS) were amplified with universal primers 27F/1492R (Monciardini et al., 2006) and designed specific primers (Xie et al., 2018), respectively. All amplicons were sequenced and deposited in GenBank with accession numbers ON723841-ON723843 and ON723846-ON723872. The BLASTn analysis of the 16S rRNA amplicons confirmed that the isolates HYC22041801-HYC22041803 belonged to the genus Pectobacterium. Phylogenetic trees based on 16S rRNA gene sequences and multilocus sequence analysis of other nine housekeeping genes of the three isolates were constructed and the results revealed that three isolates clustered with P. polaris type strain NIBIO1006T, which was previously isolated from potato (Dees et al., 2017). To confirm the pathogenicity, nine broccoli seedlings were stab inoculated with a bacterial suspension (108 CFU·ml-1), while sterile distilled liquid LB medium was used as a negative control. The seedlings were kept at 80% relative humidity and 28°C in a growth chamber. Three trials were conducted per isolate (HYC22041801-HYC22041803). After 3 days, the inoculated petioles showed soft rot symptoms similar to those observed initially in the field, while control plants remained asymptomatic. All three isolates were re-isolated successfully from symptomatic tissues to complete Koch's postulates. P. polaris has been previously reported as the causative agent of blackleg in potato in several countries, including Norway, Poland, Russia, and China (Handique et al. 2022; Wang et al. 2022). Additionally, it was reported to cause soft rot in Chinese cabbage in China (Chen et al. 2021). However, this is the first report of P. polaris causing soft rot disease in broccoli in China. This discovery is of great importance for vegetable growers because this bacterium is well established on Cruciferous vegetables in the local area, and effective measures are needed to manage this disease.

Identification and genomic insights into a strain of Bacillus velezensis with phytopathogen-inhibiting and plant growth-promoting properties

The use of biological agents offers a sustainable alternative to chemical control in managing plant diseases. In this study, Bacillus velezensis IFST-221 was isolated from the rhizosphere of a healthy maize plant amidst a population showing severe disease symptoms. The investigation demonstrated a broad-spectrum antagonistic activity of IFST-221 against eight species of pathogenic ascomycetes and oomycetes, suggesting its potential utility in combating plant diseases like maize ear rot and cotton Verticillium wilt. Additionally, our study unveiled that IFST-221 has demonstrated significant plant growth-promoting properties, particularly in maize, cotton, tomato, and broccoli seedlings. This growth promotion was linked to its ability to produce indole-3-acetic acid, nitrogen fixation, phosphate and potassium solubilization, and biofilm formation in laboratory conditions. A complete genome sequencing of IFST-221 yielded a genome size of 3.858 M bp and a GC content of 46.71%. The genome analysis identified 3659 protein-coding genes, among which were nine secondary metabolite clusters with known antimicrobial properties. Additionally, three unknown compounds with potentially novel properties were also predicted from the genomic data. Genome mining also identified several key genes associated with plant growth regulation, colonization, and biofilm formation. These findings provide a compelling case for the application of B. velezensis IFST-221 in agricultural practices. The isolate’s combined capabilities of plant growth promotion and antagonistic activity against common plant pathogens suggest its promise as an integrated biological agent in disease management and plant productivity enhancement.

Seedling-YOLO: High-Efficiency Target Detection Algorithm for Field Broccoli Seedling Transplanting Quality Based on YOLOv7-Tiny

The rapid and accurate detection of broccoli seedling planting quality is crucial for the implementation of robotic intelligent field management. However, existing algorithms often face issues of false detections and missed detections when identifying the categories of broccoli planting quality. For instance, the similarity between the features of broccoli root balls and soil, along with the potential for being obscured by leaves, leads to false detections of “exposed seedlings”. Additionally, features left by the end effector resemble the background, making the detection of the “missed hills” category challenging. Moreover, existing algorithms require substantial computational resources and memory. To address these challenges, we developed Seedling-YOLO, a deep-learning model dedicated to the visual detection of broccoli planting quality. Initially, we designed a new module, the Efficient Layer Aggregation Networks-Pconv (ELAN_P), utilizing partial convolution (Pconv). This module serves as the backbone feature extraction network, effectively reducing redundant calculations. Furthermore, the model incorporates the Content-aware ReAssembly of Features (CARAFE) and Coordinate Attention (CA), enhancing its focus on the long-range spatial information of challenging-to-detect samples. Experimental results demonstrate that our Seedling-YOLO model outperforms YOLOv4-tiny, YOLOv5s, YOLOv7-tiny, and YOLOv7 in terms of speed and precision, particularly in detecting ‘exposed seedlings’ and ‘missed hills’-key categories impacting yield, with Average Precision (AP) values of 94.2% and 92.2%, respectively. The model achieved a mean Average Precision of 0.5 (mAP@0.5) of 94.3% and a frame rate of 29.7 frames per second (FPS). In field tests conducted with double-row vegetable ridges at a plant spacing of 0.4 m and robot speed of 0.6 m/s, Seedling-YOLO exhibited optimal efficiency and precision. It achieved an actual detection precision of 93% and a detection efficiency of 180 plants/min, meeting the requirements for real-time and precise detection. This model can be deployed on seedling replenishment robots, providing a visual solution for robots, thereby enhancing vegetable yield.

Magneto-Priming of Seeds Decreases the Saline Effect of Wastewater Irrigation on Broccoli Germination and Seedling Growth

Crop plant varieties exhibit diverse reactions when subjected to wastewater irrigation in terms of seed germination, seedling development, and overall productivity. Magneto-priming, which involves treating seeds with an appropriate magnetic field, is gaining popularity as the preferred technique due to its effectiveness and environmentally friendly characteristics for improving seed vigour, growth, and plant yield. In this study, magneto-primed and non-primed broccoli seeds were irrigated with distilled or wastewater and kept under observation for a 10-day period to record seedling growth. A laboratory study was conducted to evaluate the impact of magneto-priming on broccoli seeds with a homogeneous stationary magnetic-field strength of 5.9 mT for 1 h. They were irrigated with two types of water: distilled and wastewater. Another test was performed to evaluate the effect of 1-h and 2-h magneto-priming on seed germination when seeds were irrigated with wastewater. From the results, the broccoli seedlings irrigated with distilled water grew higher and heavier than the ones irrigated with wastewater, probably due to the significant amounts of salts in organic wastewater. Nonetheless, the saline effect of wastewater was ameliorated when seeds were previously magneto-primed. All the germination parameters of broccoli seeds irrigated with wastewater were significantly reduced when seeds were magneto-primed for both periods.

Application of Tryptophan and Methionine in Broccoli Seedlings Enhances Formation of Anticancer Compounds Sulforaphane and Indole-3-Carbinol and Promotes Growth.

Broccoli is a popular cruciferous vegetable that is well known for its abundant health-promoting biochemicals. The most important of these beneficial biochemicals are glucosinolates, including glucoraphanin and glucobrassicin. Glucoraphanin and glucobrassicin can be broken down by myrosinases into sulforaphane and indole-3-carbinol, which have been demonstrated to have potent cancer-preventive properties. Efforts to increase glucoraphanin in broccoli seedlings have long been a focus; however, increasing glucoraphanin and glucobrassicin simultaneously, as well as enhancing myrosinase activity to release more sulforaphane and indole-3-carbinol, have yet to be investigated. This study aims to investigate the impact of the combined application of tryptophan and methionine on the accumulation of sulforaphane and indole-3-carbinol, as well as their precursors. Furthermore, we also examined whether this application has any effects on seedling growth and the presence of other beneficial compounds. We found that the application of methionine and tryptophan not only increased the glucoraphanin content by 2.37 times and the glucobrassicin content by 3.01 times, but that it also caused a higher myrosinase activity, resulting in a1.99 times increase in sulforaphane and a 3.05 times increase in indole-3-carbinol. In addition, better plant growth and an increase in amino acids and flavonoids were observed in broccoli seedlings with this application. In conclusion, the simultaneous application of tryptophan and methionine to broccoli seedlings can effectively enhance their health-promoting value and growth. Our study provides a cost-effective and multi-benefit strategy for improving the health value and yield of broccoli seedlings, benefiting both consumers and farmers.

Construction and Identification of Cold Tolerance in Different Broccoli Cultivars at the Seedling Stage

This study aimed to develop a systematic method for assessing the cold tolerance of broccoli seedlings, which is helpful to evaluating the cold tolerance of broccoli cultivars. We selected 14 classical broccoli cultivars and evaluated their cold tolerance by examining physiological indicators including the levels of cold resistance, electrical conductivity, malondialdehyde (MDA), soluble sugar, and hydrogen peroxide (H2O2). The results showed that there were significant differences in detected characteristics in all cultivars after cold stress during the seedling stage (p < 0.05). Among them, Meiqing had the strongest cold tolerance, followed by King 11, Zhongqing 15, Meiao 7172, Zhongqing 318, Zheqing 80, Zhongqing 16, Zhongqing 319, and Lvxiong 90. However, Zhongqing 11, Yanxiu, Qianghan, and Feicui 5, showed the worst cold tolerance (all died). Pearson correlation analysis indicated that there was a significantly negative correlation between the cold tolerance and the electrical conductivity during broccoli seedling stage, with a correlation coefficient of −0.586 (p < 0.05). At the same time, we found that the electrical conductivity of all broccoli cultivars showed a positive correlation with the MDA and soluble sugar levels, with the correlation coefficients 0.650 and 0.573, respectively (p < 0.05). This study not only firstly provides a fundamental method for evaluating the cold tolerance in different broccoli genotypes and the other cruciferous vegetables, but also offers a scientific evidence explaining the cold tolerance of the Meiqing, King 11, and Zhongqing 15 cultivars widely cultivated in China.

Glucoraphanin Accumulation via Glucoraphanin Synthesis Promotion during Broccoli Germination.

Glucoraphanin is an important glucosinolate which is widely distributed in Brassica vegetables and poses an anticancer effect to humans. Although researchers have paid a lot of attention to the changes in glucoraphanin concentration in seedlings of broccoli over 1-2 weeks, there has been little research focusing on the total whole-sprout glucoraphanin content within broccoli seedlings over 1-5 weeks. However, it is necessary to clarify the changes in total glucoraphanin content during the broccoli sprouting stage as broccoli seedlings are novel plant foods. This research explored glucoraphanin absolute accumulation and the biosynthesis mechanism in broccoli seedlings during a 5-week growth period. The results showed that glucoraphanin accumulation content was higher at week 4 than in the seeds. Moreover, the relative DL-methionine contents increased significantly after 3 weeks. Glucoraphanin synthetic gene expression levels were increased after 3 weeks, but the gene expressions of AOP3 (encoding 2-oxoglutarate-dependent dioxygenases) and MYR (encoding myrosinase) were significantly decreased. Furthermore, the 20 essential DEGs obtained can provide new insight into understanding the developmental regulation of broccoli seedlings. In addition, the results can also provide information on how to obtain higher glucoraphanin contents in broccoli sprouts.

The Effect of the Type of Tillage and Soil Mulching on some Physical Soil and the Sustainability of its Aggregate on Broccoli

An experiment was conducted in sandy clay loam soil at the research station of the College of Agriculture - Anbar University to study the effect of the type of tillage and soil mulching on some physical soil characteristics and the aggregates sustainable and broccoli yield, this experiment was designed according to the design of splinter panels with three repeaters consisting of two factors: the first tillage with three levels (zero tillage, minimum tillage and conventional tillage) and the second mulching with three levels (without mulching, polyethylene and reed). Broccoli seedlings were planted on 14/10/2022, and service operations were conducted for the crop, and the experiment continued until the plant extraction on 1/3/2023, the change in the soil bulk density, mean weight diameter, slaking value and infiltration, green plant yield and flower yield were measured, and it was noted that the soil bulk density increased at the end of the season compared to its beginning, as the soil bulk density increased by tillage and linear mulching with the progress of the season. The results showed that soil tillage significantly affected the mean weight diameter, as it increased by 8.69 and 73.91% for minimum tillage and conventional tillage respectively, while soil mulching did not affect the mean weight diameter by fast and slow wetting methods, and both tillage and soil mulching did not show any significant effect of the slaking value, but in the overlap it gave the highest value when tillage at the minimum with all types of mulching, as it reached a fixed value of 0.30 mm, and the results showed that the varieties of Aggregates Sustainable, The soil depending on the mean weight diameter by rapid wetting was within unsustainable, either slow wetting it ranged between sustainable and sustainable with another use, and sustainability was classified depending on the slaking value, as unsustainable for all treatments, and gave the highest cumulative infiltration when treating the second level of mulching and tillage, as its value was 30.6 cm min-1, and conventional tillage gave the highest moisture weight to the plant, with a value of 278.2 g plant-1, while the mulching was the highest value in polyethylene, as it reached 2207.8 g plant-1 and conventional tillage also affected significantly the flower yield as its value reached 1159 g plant-1, and the mulching affected significantly in the flower yield with a value of 1392, 1156 g plant-1 when mulched with reed and polyethylene.

Role of green synthesized nano iron oxide in alleviating the cadmium toxicity in Brassica oleracea var. italica seedlings

This work accounts for the green synthesis of iron oxide nanoparticles using Moringa oleifera leaf extract as a stabilizing and reducing agent. The preliminary confirmation of synthesized Fe3O4NPs was done by UV–visible spectroscopy in the wavelength range of 190–900 nm. The crystalline nature of Fe3O4 NPs was established via X-ray diffraction analysis. FT-IR studies reveal the bioactive phytochemicals present in the Moringa leaf extract based Fe3O4 NPs. A DLS particle size analyser was used to determine the size of green synthesized Fe3O4 NPs and its spherical morphology was determined by using SEM and TEM techniques. The growth of Brassica oleracea var. italica seedlings was measured by analysing biophysical and biochemical parameters in two concentrations of Fe3O4 NPs i.e. 15 mg/L and 30 mg/L alone and in combination with cadmium. Treatments were designated as control C, NP1, NP2, Cd+NP1, Cd+NP2, and Cd. Fe3O4 NPs treated broccoli seedlings showed noteworthy improvement in shoot length, root length, plant biomass, total chlorophyll content, carotenoid content, total soluble sugars, protein content, and nitrate reductase activity, while decline in electrolyte leakage, lipid peroxidation, proline content, superoxide dismutase activity and catalase activity was reported as compared to control. Exposure of iron oxide nano-treatments was found efficacious in reducing cadmium accumulation at a concentration of 30 mg/L. The seedlings exposed to NP2 (30 mg/L) concentration of green synthesized nano iron oxide increased nutrient uptake and thus stimulating plant growth, and also improved morphological and physiological characteristics of Brassica oleracea seedlings. Therefore, the present study reported that bio-based iron oxide nanoparticles were significantly useful for plant growth, by enhancing the plant defense mechanism in response to cadmium induced toxicity.

First Report of Exserohilum rostratum Causing Leaf Blight on Broccoli (Brassica oleracea var. italica) in China.

Broccoli (Brassica oleracea var. italica) is not only an important crop worldwide with a large amount of production and consumption annually, but also rich in biologically active compounds (Surh et al., 2021). In November 2022, an unknown leaf blight was observed in the Broccoli planting area, Wenzhou City of Zhejiang Province (28.05 °N, 120.31 °E). Symptoms initially occurred at the leaf margin with yellow to gray lesions that were irregular and wilting. Approximately 10% of the surveyed plants were affected. To determine the pathogen, leaves with blight were collected randomly from five B. oleracea plants. Tissue blocks (3×3 mm) from diseased leaf portions were disinfected with 75% ethanol, rinsed three times with sterilized water, placed aseptically onto potato dextrose agar (PDA) medium, and incubated for 5 days at 28℃ in darkness. Seven fungal isolates with the same morphology were obtained using the spore method. The observed colonies were circular, taupe, pewter in color with light gray edging and many cottony aerial mycelia. Conidia were straight, curved or slightly bent, ellipsoidal to fusiform, and septate (typically 4-8 septa per conidium), with the size of 50.0-90.0 μm × 10.0-20.0 μm (n=30). The conidia had a slightly protruding and truncate hilum. These morphological characteristics were consistent with Exserohilum rostratum (Sharma et al., 2014). To further identify the pathogen, isolate WZU-XLH1 was chosen as a representative and the internal transcribed spacer (ITS) and glyceraldehyde-3-phosphate dehydrogenase-like (GAPDH) gene were amplified and sequenced using primer pairs ITS1/ITS4 (White et al., 1990) and Gpd1/Gpd2 (Berbee et al., 1999), respectively. The ITS and gpd gene sequences of isolate WZU-XLH1 were deposited in the GenBank database with accession numbers OQ750113 and OQ714500, respectively. BLASTn analysis showed matches of 568/571 (MH859108) and 547/547 (LT882549) with Exserohilum rostratum CBS 188.68. A neighbor-joining phylogenetic tree was constructed by combining the two sequenced loci, this isolate in the E. rostratum species complex clade at 71% bootstrap support.To verify the pathogenicity of the isolate, ten healthy Broccoli (cultivar 'You Xiu') seedlings with at least five leaves were divided into two groups: one group was inoculated with the isolate, while the other group served as a control. After surface disinfection with 75% ethanol and wiping with sterile water, tiny wounds were made on two leaves (two wounds in one leaf) using an inoculation needle. Fungal culture plugs cut from the isolate were placed on the wounds, while sterile PDA plugs served as the control. The leaves were sealed in wet airtight bags to retain moisture at room temperature with natural light (Cao et al., 2022). After five days, all leaves inoculated with isolate WZU-XLH1 showed symptoms identical to those observed in the field, with no symptoms present in the control group. The pathogenicity was confirmed by repeating the test in triplicate, and fungi re-isolated from symptomatic leaves were identified as E. rostratum by the morphological and molecular methods described above. To the best of our knowledge, this is the first report of E. rostratum causing leaf blight on broccoli in China. This study contributes to our understanding of B. oleracea leaf blight and establishes a basis for future studies on E. rostratum to develop management strategies.

Identification and Characterization of Beneficial Soil Microbial Strains for the Formulation of Biofertilizers Based on Native Plant Growth-Promoting Microorganisms Isolated from Northern Mexico.

Plant growth-promoting microorganisms (PGPM) benefit plant health by enhancing plant nutrient-use efficiency and protecting plants against biotic and abiotic stresses. This study aimed to isolate and characterize autochthonous PGPM from important agri-food crops and nonagricultural plants to formulate biofertilizers. Native microorganisms were isolated and evaluated for PGP traits (K, P, and Zn solubilization, N2-fixation, NH3-, IAA and siderophore production, and antifungal activity against Fusarium oxysporum). Isolates were tested on radish and broccoli seedlings, evaluating 19 individual isolates and 12 microbial consortia. Potential bacteria were identified through DNA sequencing. In total, 798 bacteria and 209 fungi were isolated. Isolates showed higher mineral solubilization activity than other mechanisms; 399 bacteria and 156 fungi presented mineral solubilization. Bacteria were relevant for nitrogen fixation, siderophore, IAA (29-176 mg/L), and ammonia production, while fungi for Fusarium growth inhibition (40-69%). Twenty-four bacteria and eighteen fungi were selected for their PGP traits. Bacteria had significantly (ANOVA, p < 0.05) better effects on plants than fungi; treatments improved plant height (23.06-51.32%), leaf diameter (25.43-82.91%), and fresh weight (54.18-85.45%) in both crops. Most potential species belonged to Pseudomonas, Pantoea, Serratia, and Rahnella genera. This work validated a high-throughput approach to screening hundreds of rhizospheric microorganisms with PGP potential isolated from rhizospheric samples.

Strategies for reducing the impact of clubroot on broccoli cultivation in tropical mountain regions

Brassica spp. production can be negatively affected by clubroot, which is caused by the protozoan Plasmodiophora brassicae Woronin. Most of the information on clubroot control is derived from studies in temperate regions. Here, management strategies were evaluated to reduce broccoli (Brassica oleracea L. var. italica Plenck) crop losses owing to clubroot in tropical mountain regions. The first experiment revealed the effect of green manure from coriander (Coriandrum sativum L.), sunn hemp (Crotalaria juncea L.), sweet corn (Zea mays L.), and spontaneous vegetation (control) associated with broccoli seedlings of 4 different sizes. In the second experiment, the effect of soil amendments (limestone and steel slag) in conjunction with poultry litter (fresh or composted for 45 days) and without poultry litter (control), was assessed. Both field experiments sought to evaluate the disease intensity, plant development (root growth, biomass, and nutrient accumulation), and yield. Sunn hemp and coriander biomass resulted in higher healthy root volumes and dry weights of broccoli. However, such benefits were not derived from corn treatment. Compared to smaller seedlings (10 mL cell and 20 days of age, and 16 mL cell and 24 days of age), the use of larger seedlings (35 mL cell and 28 days of age, and 50 mL cell and 32 days of age) resulted in lower intensity of clubroot and increased the average yield by 143% in summer crops. Steel slag, like limestone, corrected soil acidity and resulted in plant growth; however, clubroot intensity was not significantly affected. Fresh and composted poultry litter increased the percentage of diseased roots compared with the control; however, broccoli yield was not affected by the treatments. Using green manure (sunn hemp or coriander) and well-developed seedlings is recommended as a strategy to reduce losses induced by clubroot during broccoli cultivation.

Comparative anatomical and hormonal analyses between kohlrabi and broccoli seedlings: Relevance to kohlrabi stem tuber initiation

To unveil the mechanism of tuberous stem formation at early growth stages in kohlrabi, the comparative stem morphology, anatomy, and endogenous plant hormone profiles were studied at different days after germination (10 to 30 DAG). Stem anatomy revealed that the notable feature of the kohlrabi stem during the transition from primary to secondary growth was the formation of vascular bundle circles, with many phloems formed separately and arranged in a circular pattern along with the cambium layer, resulting in an expanded ring of primary and secondary phloem. In addition, medullary supplemental vascular bundles were differentiated in the central region of pith and successively supplied small-sized meristematic parenchymatous cells which contribute to the tuber initiation in kohlrabi. Six phytohormones were quantified in the stems and leaves of both genotypes. The absence of Gibberellin A4 (GA4) in kohlrabi stem might be the cause of the stunted stem of kohlrabi. The total endogenous cytokinin in stem of kohlrabi was more than twice of that of broccoli, where trans-zeatin was the most abundant bioactive form. This can be explained by the meristematic nature of the cambium of kohlrabi stem. Profiles for Indole-3-acetic acid, Indole-3-acetylaspartic acid, and Abscisic acid of the stems and leaves of kohlrabi and broccoli were significantly different at several time points tested. Thus, the key features of kohlrabi during the initiation of tuberous stem were the formation of the phloem ring along with the cambium and the supplemental vascular bundles. This is the first paper showing the hormonal profile in the early seedling stage of kohlrabi. These findings provide useful information to elucidate the mechanism of tuberous stem formation of kohlrabi and other tuber crops.

High Growing Temperature Changes Nutritional Value of Broccoli (Brassica oleracea L. convar. botrytis (L.) Alef. var. cymosa Duch.) Seedlings.

High temperature (HT) causes physiological and biochemical changes in plants, which may influence their nutritional potential. This study aimed to evaluate the nutritional value of broccoli seedlings grown at HT on the level of phytochemicals, macro- and microelements, antioxidant capacity, and their extracts' in vitro cytotoxicity. Total phenols, soluble sugars, carotenoids, quercetin, sinapic, ferulic, p-coumaric, and gallic acid were induced by HT. Contrarily, total flavonoids, flavonols, phenolic acids, hydroxycinnamic acids, proteins, glucosinolates, chlorophyll a and b, and porphyrins were reduced. Minerals As, Co, Cr, Hg, K, Na, Ni, Pb, Se, and Sn increased at HT, while Ca, Cd, Cu, Mg, Mn, and P decreased. ABTS, FRAP, and β-carotene bleaching assay showed higher antioxidant potential of seedlings grown at HT, while DPPH showed the opposite. Hepatocellular carcinoma cells were the most sensitive toward broccoli seedling extracts. The significant difference between control and HT-grown broccoli seedling extracts was recorded in mouse embryonal fibroblasts and colorectal carcinoma cells. These results show that the temperature of seedling growth is a critical factor for their nutritional value and the biological effects of their extracts and should definitely be taken into account when growing seedlings for food purposes.

Produção de brócolis em plantio direto com diferentes coberturas vegetais e doses de nitrogênio

ABSTRACT No-till vegetable farming is a feasible alternative to reduce erosion-induced losses and to increase soil nutrient availability, because cover crop residue protects the soil and its decomposition promotes nutrient cycling, which can improve the yield of the subsequent crop. The present study assessed the production and decomposition of cover crops and the agronomic performance of broccoli grown on this residue using different nitrogen doses in a no-till system. A randomized block design was used, in a split-split plot arrangement of main plots (cover crops), sub-plots (N doses) and sub-sub plots (decomposition times), with four repetitions. Seven cover crops were studied, as follows: [1) signal grass (SG); 2) sunn hemp (SH); 3) pearl millet (PM): 4) SG+SH; 5) SG+PM; 6) SH+PM and 7) SG+SH+PM]; in addition to four doses of nitrogen topdressing [T1) no N application (control); T2) 60 kg/ha N; T3) 90 kg/ha N and T4) 120 kg/ha N]; and five cover crop residue decomposition times: zero (cutting), 15, 30, 60 and 90 days after transplanting (DAT) the broccoli seedlings. Cover crop dry weight (DW) production, residue decomposition, and the head fresh (HFW) and dry weight (HDW) and yield (YLD) of broccoli were assessed. Among the cover crops, sunn hemp and the intercropped SG+SH treatment exhibited the lowest DW production and, along with signal grass, the shortest half-life (T½) and highest residue decomposition rate. The best-performing broccoli plants were those grown using PM, SH and a combination of both as cover crops. The highest broccoli production was obtained using sunn hemp residue, regardless of nitrogen topdressing, with HFW of 788 g/plant and YLD of 30 t/ha.

Manejo da adubação verde e orgânica com composto fermentado no cultivo agroecológico de brócolis americano

ABSTRACT This work aimed to evaluate the phytotechnical performance of the succession involving pre-croppings of maize and Mucuna pruriens (velvet bean) or the intercropping of these species in the agroecological cultivation of broccoli in the presence and absence of fermented compost fertilization. The experimental design was in randomized blocks in a factorial scheme 2 (maize monoculture or intercropped with velvet bean) x 2 (absence and presence of fermented compost fertilization) + 1 (velvet bean monoculture and without fertilization). After cutting the maize and velvet bean biomass, the broccoli seedlings were transplanted. In this stage, the design was in randomized blocks in a 3-factorial scheme (maize monoculture; maize intercropped with velvet bean; velvet bean monoculture) x 2 (presence and absence of fermented compost fertilization). The authors concluded that when the velvet bean was introduced into maize cultivation system no negatively interference was noticed concerning to phytotechnical components of baby corn, and it even allows an additional of 3.46 and 7.75 t/ha of fabaceous phytomass, respectively, in the first and second year. In the absence of fertilization, phytomasses of the intercroppings provided broccoli productivity of 12.87 t/ha, which represents an increase of 43.73% when compared to maize monoculture in the second year. An effect of fertilization with the fermented compost on broccoli cultivation under these study conditions was verified, providing a greater accumulation of N in the inflorescences in the first year and maximum productivity of 12.19 and 14.32 t/ha, respectively, first and second years.