Roots Of Strawberry Plants Research Articles

Antagonistic Strain Bacillus velezensis JZ Mediates the Biocontrol of Bacillus altitudinis m-1, a Cause of Leaf Spot Disease in Strawberry.

Biofertilizers are environmentally friendly compounds that can enhance plant growth and substitute for chemically synthesized products. In this research, a new strain of the bacterium Bacillus velezensis, designated JZ, was isolated from the roots of strawberry plants and exhibited potent antagonistic properties against Bacillus altitudinis m-1, a pathogen responsible for leaf spot disease in strawberry. The fermentation broth of JZ exerted an inhibition rate of 47.43% against this pathogen. Using an optimized acid precipitation method, crude extracts of lipopeptides from the JZ fermentation broth were obtained. The crude extract of B. velezensis JZ fermentation broth did not significantly disrupt the cell permeability of B. altitudinis m-1, whereas it notably reduced the Ca2+-ATPase activity on the cell membrane and markedly elevated the intracellular reactive oxygen species (ROS) concentration. To identify the active compounds within the crude extract, QTOF-MS/MS was employed, revealing four antimicrobial compounds: fengycin, iturin, surfactin, and a polyene antibiotic known as bacillaene. The strain JZ also produced various plant-growth-promoting substances, such as protease, IAA, and siderophore, which assists plants to survive under pathogen infection. These findings suggest that the JZ strain holds significant potential as a biological control agent against B. altitudinis, providing a promising avenue for the management of plant bacterial disease.

First report of a new bacterial stem rot disease of strawberry (Fragaria×ananassa) caused by Pantoea ananatis in Jiangsu, China.

Strawberry (Fragaria×ananassa Duch.) is an important economic fruit crop in the world. With the continuous expansion of strawberry planting area, strawberry disease is one of the most important limiting factors, which seriously affects the agronomic performance and leads to significant economic losses. In November 2020, an infected stem rot disease of strawberries was detected in the strawberry growing area of Donghai County, Jiangsu Province, China. The disease incidence ranged from 30 % to 45 %. Initially, infected plants included stunted growth of new leaves, leaflet asymmetry, and holes in the vertical section of the stem, resulting in leaf blight and death in severe cases. To isolate the pathogen, two symptomatic plants were randomly collected. And then infected plants were surface sterilized with 75 % ethanol for 1 min, followed by 2 % sodium hypochlorite for 6 minutes. After that, the infected plants were washed 4-5 times with double sterilized distilled water, cut into 3-5 mm small pieces, and soaked in 2 ml of sterile water for 15 min, after which 100 µl of liquid suspension were spread onto Luria-Bertani medium (LB) and incubated at 28 °C for 12-16 h. All isolates showed yellow, viscous, round, and smooth (Figure S1, C) and the isolates were designated as JX1 and JX2. To identify the pathogen, the genomic DNA were extracted from isolates using the Ezup Column Bacteria Genomic DNA Purification Kit (Sangon Biotech, China) and the fragments of gyrB, rpoB and leuS gene were amplified using the primer pairs UP-1S/UP-2Sr (Yamamoto and Harayama 1995), rpoB-F/rpoB-R and leuS-F/leuS-R (Yu et al. 2022), respectively. Sequence analyses showed that the nucleotide sequences of gyrB, rpoB, and leuS fragments of the isolates shared 99.72 %, 99.67 % and 98.37 % identity with the Pantoea ananatis type strain LMG 2665 (KF482590.1, EF988972.1 and KF482626.1, respectively ), which suggests that the isolate could be Pantoea ananatis. To further verify that P. ananatis was identity of these isolates, the whole genome was sequenced using PacBio sequel II technology. The Average Nucleotide Identity (ANI) calculation showed that the whole-genome sequence was 99.0% similar to that of the Pantoea ananatis type strain LMG 2665 (Jain et al. 2018). The isolates were therefore recognized as P. ananatis. To confirm pathogenicity, roots of strawberry plants were inoculated by wounding as described (Wang et al. 2017) with bacterial suspensions (108 CFU/ml) for 30 min, and transplanted into 10 cm ×8.5 cm pots filled with substrate (peat: perlite: vermiculite =3:1:1). The negative control plants were inoculated with sterile distilled water (20 individual plants per group). All infected plants were placed in a greenhouse under the following environmental conditions: 30 ℃/25 ℃ day/night, >70 % relative humidity, 16-h/8-h photoperiod. The experiment was carried out three times. After 3 to 4 weeks of inoculation, the new leaves of the plants were smaller and asymmetrical, while the negative plants remained healthy. After 8 weeks, a significant stem rot pocket developed on all inoculated plants, similar to the symptoms observed in the field. In contrast, no symptoms were observed in negative plants (Figure S2). To fulfill Koch's postulates bacteria were further isolated, purified and identified from the greenhouse inoculated plants. The results proved that the causative agent of strawberry stem rot was P. ananatis. In recent decades, P. ananatis has been found to cause bacterial leaf blight in strawberries (Bajpai et al. 2020). It has also caused other crop diseases, such as maize white spot, peach soft rot and others (Cui et al.2022; Liao et al. 2015). Although other crop diseases caused by P. ananatis, a bacterial pathogen, there has been no report of P. ananatis causing the symptoms of stem rot disease in strawberry. To our knowledge, this is the first report of P. ananatis causing stem rot in strawberry. This study provides solid evidence that strawberry stem rot disease in China can also be caused by the novel pathogen Pantoea ananatis. In conclusion, this report will provide a theoretical reference for the prevention and control measures of P. ananatis causing strawberry stem rot disease in the future.

Regularities of accumulation of heavy metals by strawberry (Fragaria×Ananassa Duch.) plants from soddy-podzoly soil using adsorbents based on mineral and polymeric substances

In vegetative experiment has been studied the infl uence of adsorbents on the basis of mineral and polymer substrates Bentonite, Arpolit, Supradit, Agronit on the accumulation of heavy metals (HM) of strawberry plants plant variety Troitskaya in the artificial contamination of sod-podzolic soil at the level MAC (maximum allowable concentration) of total content of TM: Cd 2 mg/kg, Cr 100 mg/kg (MAC missing), Pb 130 mg/kg, Zn 220 mg/ kg. It was found that the use of adsorbents based on mineral and polymer substrates helps to reduce the content of mobile forms of Cr, Cd, Pb in the soil. Their content is reduced to the greatest extent when the adsorbents Supradit M are added to the soil (by 78.5 % for Cd and 40.1 % for Pb, compared with the control) and Agronite (by 79.0 % for Cd and 48.9 % for Pb, compared with the control). For mobile Cr, the downward trend in soil content was statistically unreliable. The content of mobile Zn in the variants with all adsorbents, on the contrary, increased in comparison with the contaminated control, to the greatest extent when the adsorbent Supradit M was added – by 26.1 %, compared with the control. The use of adsorbents led to a decrease in the content of Cd and Pb in the roots of strawberry plants. The greatest decrease in their content in the roots was when adding adsorbents Supradit M (65.2 % for cadmium and 76.8 % for lead, compared with the control) and Agronite (65.7 % for cadmium and 78.2 % for lead, compared with the control). The content of Zn in the roots in the variants with the introduction of adsorbents, except for Bentonite, increased in comparison with the contaminated control, to the greatest extent with the introduction of the adsorbent Supradit M – by 45.2 %. The content of Cr in the roots when using all adsorbents, except Agronite, also tended to increase, to the greatest extent when applying Arpolite – by 105.9 %, compared with the control. When applying the adsorbents Supradit M and Agronit to the soil, the content of Cd in the leaves decreased: when applying the adsorbent Supradit M by 52.9 %, Agronit – by 41.2 %, compared to the control. The content of Zn, Cr, and Pb in the leaves in the variants with adsorbents increased in comparison with the contaminated control, to the greatest extent when adding the adsorbent Arpolite: by 63.7 % – for Zn, by 71.2 % – for Cr, and by 46.3 % – for Pb. When using this adsorbent, the content of Cd in the leaves also increased – by 105.9 % higher than the contaminated control. The content of Cd, Cr, Pb, Zn in the berries of strawberry when using adsorbents less than in the roots and leaves, depended on the content of the corresponding heavy metals in the soil and was not statistically significant. When adding the adsorbents Supradit M and Agronit to the soil, the content of Cd in berries tended to decrease: when using the adsorbent Supradit M – by 30.0 %, Agronit – by 40.0 %, compared with the control. When adding the adsorbent Arpolite to the soil, the Cd content in berries tended to increase by 30.0 %, Pb – by 111.8 % from the control. The Cr content in the berries in the variants with adsorbents increased in comparison with the contaminated control, to the greatest extent with the introduction of Bentonite adsorbent – by 180.0 %. For the content of Zn in berries, there was no pronounced natural tendency for adsorbents to act. The closest relationship between the content of TM in the organs of strawberry plants and the content of mobile forms of heavy metals in the soil was observed for roots and leaves. There was no such dependency for Cr. At the studied levels of mobile TM content in the soil, the barrier properties of strawberry plants play an important role in the accumulation of heavy metals. The translocation coefficients of heavy metals were higher in the experiment variants, in which a decrease in the content of mobile forms of TM in the soil was observed when adding adsorbents. For Cd in the variant using the adsorbents Supradit M and Agronit, the TM translocation coefficients were higher than the control value by 98.0 and 72.5 %, respectively. For Pb, the values of translocation coefficients increased with the use of these adsorbents, compared to the control, by 300 % and 350 %, respectively. With an increased content of mobile forms of TM in the soil in the variants with the introduction of adsorbents Supradit M and Agronit, the translocation coefficients for Zn, compared to the control, were lower by 33.3 % and 33.3 %, respectively.

Potassium deficiency and root exudates reduce root growth and increase Fusarium oxysporum growth and disease incidence in continuously cultivated strawberry

ABSTRACTStrawberry fruits are increasingly produced under continuous cultivation and K deficiency, but the response of strawberry to this combination of stresses has not been extensively studied. Pot and tissue culture grown strawberry (Fragaria ananassa Duch.) plants were used to determine the effect of strawberry root exudates on the growth of strawberry plants and Fusarium oxysporum under continuous cultivation and potassium (K) deficiency. The pot experimental results showed that the Fusarium wilt disease rating and index were very high (62% and 86, respectively), and the lateral roots of strawberry plants were significantly restricted under the continuous cultivation and K deficiency treatment. The growth of tissue culture plantlets was inhibited by a high concentration (4%) and promoted by a low concentration (1%) of root exudates from the replanted pot strawberries. The number of lateral roots of tissue culture plantlets was significantly lower in the 4% root exudate treatment. Growth of F. oxysporum was promoted by the relatively high concentration of root exudates of the replanted pot strawberry under continuous cultivation and K deficiency. Total phenolics and three individual phenolics (ferulic acid, p-coumaric acid and cinnamic acid) were detected in the rhizosphere soil of replanted pot strawberries and were higher in the K-deficiency treatments. Fusarium oxysporum growth was promoted by the addition of exogenously added phenolic acids. A positive relationship was observed between the growth of F. oxysporum and the higher concentration ranges of ferulic acid and p-coumaric acid.

Root Growth, Mycorrhizal Frequency and Soil Microorganisms in Strawberry as Affected by Biopreparations

The aim of the study was to assess the effects of various biopreparations on the growth of the strawberry root system, the number of spores of mycorrhizal fungi, the total number of bacteria in the rhizosphere soil, and the degree of mycorrhizal association in the roots of two strawberry cultivars. The experiment with strawberry plants was established in the spring of 2010 in the Experimental Orchard of the Institute of Horticulture in Dabrowice. The objects of research were “frigo” strawberry plants of the cultivars Elsanta and Elkat. The following experimental combinations were used: control, control NPK (standard NPK fertilization), manure, mycorrhizal preparation Micosat F, Humus UP, Humus Active + Aktywit PM, BioFeed Amin, BioFeed Quality, Tytanit, Vinassa, Florovit Eko, and Florovit Pro Natura. The use of the biopreparation BioFeed Quality resulted in a six-fold increase in root length and a seven-fold increase in root surface area. Compared with NPK fertilization, application of the preparation BioFeed Amin contributed to an eight-fold increase in root volume, and the use of Vinassa increased 24-fold the number of root tips of Elkat strawberry plants. Micosat F and Humus UP caused a five-fold increase in mycorrhizal frequency in the roots of strawberry plants. Micosat F and manure contributed to a two- and four-fold increase, respectively, in the number of spores in the rhizosphere soil. Application of the preparations Humus UP, BioFeed Amin and Florovit Eko doubled the total number of bacteria and filamentous fungi in the rhizosphere soil of strawberry plants of the cultivars Elsanta and Elkat in comparison with NPK fertilization. Fertilization with the biopreparations intensified the growth of the root system and increased the number of spores of AM fungi, mycorrhizal frequency, and the total number of bacteria and filamentous fungi in the soil.

Influence of soil type, cultivar and Verticillium dahliae on the structure of the root and rhizosphere soil fungal microbiome of strawberry.

Sustainable management of crop productivity and health necessitates improved understanding of the ways in which rhizosphere microbial populations interact with each other, with plant roots and their abiotic environment. In this study we examined the effects of different soils and cultivars, and the presence of a soil-borne fungal pathogen, Verticillium dahliae, on the fungal microbiome of the rhizosphere soil and roots of strawberry plants, using high-throughput pyrosequencing. Fungal communities of the roots of two cultivars, Honeoye and Florence, were statistically distinct from those in the rhizosphere soil of the same plants, with little overlap. Roots of plants growing in two contrasting field soils had high relative abundance of Leptodontidium sp. C2 BESC 319 g whereas rhizosphere soil was characterised by high relative abundance of Trichosporon dulcitum or Cryptococcus terreus, depending upon the soil type. Differences between different cultivars were not as clear. Inoculation with the pathogen V. dahliae had a significant influence on community structure, generally decreasing the number of rhizosphere soil- and root-inhabiting fungi. Leptodontidium sp. C2 BESC 319 g was the dominant fungus responding positively to inoculation with V. dahliae. The results suggest that 1) plant roots select microorganisms from the wider rhizosphere pool, 2) that both rhizosphere soil and root inhabiting fungal communities are influenced by V. dahliae and 3) that soil type has a stronger influence on both of these communities than cultivar.

Lateral root formation in the strawberry Fragaria × ananassa Duch. revealed by histone H4 in situ hybridisation

Our study was carried out in bench rhizotrons using the Camarosa variety of strawberry (Fragaria × ananassa Duch.), by exciding the apex of fast-growing primary roots at two distances (1 or 8 cm) from the apex. It was demonstrated that new lateral meristems were rapidly induced by excision of the root apex at either distance; after 24 h, histone H4 in situ hybridisation detected groups of cell-organising root primordia just a few millimetres below the cut. After a further 24 h, new lateral roots were about to protrude from the original root. Results show that lateral roots can be formed anywhere along the primary roots of strawberry plants from a few stem cells distributed along the pericycle close to the protoxylem arches.

Salicylic acid ameliorates the adverse effect of salt stress on strawberry

Strawberry is considered as a salinity sensitive species and is adversely affected in response to the salt stress in terms of growth and yield. Pot experiments were conducted to determine the effect of exogenous salicylic acid (SA) application on physiology, growth, chlorophyll and mineral content of strawberry grown under salt stress and greenhouse conditions. Strawberry plants were treated with SA at different concentrations (0.0, 0.25, 0.50 and 1.00 mM). Salinity treatments were established by adding 0 and 35 mM of NaCl to a base complete nutrient solution. Salt stress negatively affected the growth, chlorophyll content and mineral uptake of strawberry plants. However, plants treated with SA often had greater shoot fresh weight, shoot dry weight, root fresh weight and root dry weight as well as higher chlorophyll content under salt stress. The greatest values were obtained with 1.00 mM SA treatment in both saline and non-saline conditions. Leaf water relative content (LWRC) was reduced in response to salt stress while electrolyte leakage was raised. SA treatments induced increases in LWRC and decreases in electrolyte leakage compared to the control under salt stress. With respect to the nutrient content, SA treatments increased almost contents of all nutrients in leaves and roots of strawberry plants under salt stress. The greatest values were often obtained by the 1.00 mM SA treatment. These findings suggest that the SA treatments can ameliorate the negative effect of salinity on the growth of strawberries.

Activated Carbon Root Dips on Transplanted Strawberries

Excellent protection from 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) injury at twice the dose needed for weed control was obtained by dipping the roots of strawberry plants (Fragaria grandifloraEhrh.) in a 10% slurry of activated carbon before transplanting. Protection was greater when the roots were dipped in the slurry of activated carbon than when activated carbon was applied in the transplant water. Protection was obtained from three different activated carbons. Protection from injury to varying degrees was observed when several other herbicides were used.