Endophytic bacteria from Jatropha curcas suppress Meloidogyne spp. and promote eggplant growth under greenhouse conditions

The ojectives of this research were to study effect of media composition and foliar fertilizer of NOVELGRO concentration on growth Jatropha curcas . Experimental design used was a factorial 3x4 with three replications. Factors investigated were growth media composition with a ratio of 1:1:1 (soil, compost, sand), (soil, compost, and rice husk), (soil, compost, saw dust), and Novelgro concentration of 0, 1, 2 and 3 cc/L of water. Results showed that there was a significant effect of growth media composition on plant growth and leaf number at 35, 45 and 55 day after planting (DAP), stem diameter at 45 and 55 DAP, fresh weight, dry weight and dry weight of root, but the media composition did not show significant effect on plant growth and leaf number at 25 DAP and stem diameter at 25, 35 DAP. The best growth was found at media composition of soil, compost and sand with a ratio of 1:1:1. Fertilizer concentration significantly affected stem diameter at 25 DAP but did not show a significant affect on plant growth and leaf number at 25, 35, 45, and 55 DAP, stem diameter at 35, 45, and 55 DAP, fresh weight, dry weight and dry weight of root. Plant growth was best at a fertilizer concentration of 2cc/L of water. There was no significant interaction between growth media composition and fertilizer concentration on all variables observed.

When enemies attack do plants get by with a little help from their friends?

Simple SummaryChia is an important medicinal plant and is a rich source of omega-3 and omega-6 fatty acids. Alkaline soil inhibits the growth and productivity of all crops, including chia. Microalgae are a diverse group of photosynthetic microorganisms that can be used in modest doses to stimulate the growth and productivity of numerous crops in both normal and stressed conditions. Microalgae supplementation by two application methods (foliar spray and soil drench) resulted in an increase in the growth and productivity of chia plants cultivated under alkaline stress conditions, and caused an increase in the antioxidant levels in the chia seeds, although soil drenching gained the superiority in this respect. The oil content was increased following microalgae application with an increase in omega-3 proportion. Chia plants showed different responses to foliar and drenching applications. Microalgae would be a potential and eco-friendly approach for enhancing agricultural productivity in alkaline environments. Our findings also suggest that Arthrospira platensis supplementation via the soil drenching technique should be used in the future to enhance plant growth and productivity under alkaline soil conditions.Alkaline soil inhibits the growth and productivity of chia plants (Salvia hispanica L.). Microalgae as biofertilizers have been reported to induce alkalinity tolerance and enhance yield and quality. However, limited information is known concerning the influence of microalgae application on medical plants, including chia. Our experiments were performed to evaluate the effect of microalgae strains of Arthrospira platensis, Chlorella vulgaris, Nostoc muscorum, and Anabaena azollae with two application methods, foliar spray and soil drench, on morpho-physiological and biochemical parameters, yield, seed and oil quality, and fatty acid profiles of chia plants cultivated under alkaline soil conditions, as well as the on soil microbial activity. The results obtained reveal that both application methods positively influenced the growth and productivity of chia plants. However, the foliar application showed significant differences in the herb’s fresh and dry weights and leaf pigments, whereas the drenching application caused more effect than the foliar spray application at the reproductive stage. Untreated chia plants showed a slight decline in the growth, productivity, and antioxidant level with an increase in Na content. However, microalgae applications significantly ameliorated these impacts as they induced an enhancement in the growth, leaf pigments, total protein and carbohydrate contents, nutrient content, seed and oil yields, as well as an increase in linolenic and linoleic fatty acids, with a reduction in saturated fatty acids, namely, palmitic and lauric acid. Soil drenching generated an improvement in the soil microbial activity and caused a reduction in the pH. The treatment of A. platensis with drenching application resulted in higher seed and oil yield, with an increase of 124 and 263.3% in seed and oil yield, respectively.

Biological control of Phomopsis leaf blight of brinjal (Solanum melongena L.) with combining phylloplane and rhizosphere colonizing beneficial bacteria

The impact of potassium humate, ammonium humate and vermicompost tea on the root-knot nematode, Meloidogyne arenaria, and their effect on plant growth and some biochemical parameters in eggplant were determined in vitro and in vivo. The in vitro results showed that egg hatching and juvenile mortality of M. arenaria were significantly (P ≤ 0.05) affected by treatments. Ammonium humate 3 and 2% were more effective in inhibiting egg hatching after 4 days by 61.6 and 82.6% respectively. Also, in ammonium humate 3%, the increase of exposure period from 24 to 48 hrs. raised mortality from 73.3 to 82%. In vivo experiment treatments were applied under greenhouse conditions with two different application methods (soil drenching, and foliar spray) and two concentrations (2 and 3%) on the root-knot nematode, M. arenaria population, and their impact on eggplant. All tested treatments significantly decreased nematode number to different levels compared to control. The highest suppression in total nematode population was recorded with drenching by 3% ammonium humate. A similar trend was noticed with reproduction factor and number of galls or egg- masses per root system. Plants grown in soil drenched by 3 % ammonium humate recorded the highest value in fresh and dry weight, as well as shoot and root length. Also, these plants gave the highest values of carotenoids, phenolic compounds and total amino acids. While, the highest value of proline content appeared with control. Also, the results showed that the total chlorophyll, total protein and reducing sugar content increased in all treatments compared to control.

Cucumber (Cucumis sativus L.) is one of the most important vegetables cultivated in the world. It is widely cultivated and mostly grown under greenhouse conditions (Sallam et al. 2021). Cucumber has a long growth cycle and is particularly susceptible to bacterial diseases. In May 2021, bacterial leaf spot was found on cucumbers of the variety Lyuyou NO.3 in Hainan Province, China. In the early stage of the disease, the leaves showed small yellow-brown spots in the shape of water stains. When exposed to light, a yellow halo around the disease spots could be seen. In later stages, the lesions gradually become larger and more yellow. The leaf veins around the disease site also gradually turned yellow (Figure 2a). In serious cases, the whole leaf turned yellow, resulting in leaf death. We collected plants with the same symptoms from 25 different farms in Hainan Province. Five plants were selected from each farm by the classic five-point sampling method and three leaves were selected from each plant, for a total of 15 leaves collected from each farm. Then three leaves were randomly selected from the 15 leaves on each farm for isolation of the pathogen, and a total of 75 leaves were isolated. We found that the incidence of the disease was from 20% to 30% based on a diagnostic test, which conducted on 75 cucumber leaves samples suspected of same symptom of cucumber, collected from Hainan Province. Using microscopy, bacterial streaming was observed to tentatively identify the causal agent as a bacteria. Tissue isolation was used to isolate the responsible pathogens. A 5 mm × 5 mm sample of tissue at the junction of diseased and healthy sections was collected. First, the surface of the tissue was disinfected in a 75% ethanol solution for 30 sec; then it was soaked in 2% NaOCl for 5-7 min, and finally, it was washed thrice in sterile distilled water. The tissues were inoculated onto lysogen broth culture media (LB) and cultured in a 28℃ incubator for 2 days. Bacterial colonies that emerged from the tissues were cultured in LB. Four isolated colonies were selected for verification. The colonies of isolated from the diseased leaves of cucumber are round, egg yellow and slightly sticky (Figure 2c). The isolate named PA-1 was identified by PCR amplification and sequencing of the partial 16S rRNA gene with the primer 27F/1492R (Lane 1991) and gyrB gene (Li et al. 2019). Sequences were stored in GenBank with the accession numbers OK576932.1 (16S rRNA, PA-1) and OL978577 (gyrB); BLASTn was used to compare these with other GenBank sequences. Sequencing of the 16S rRNA gene showed that PA-1 had a sequence length of 1403bp, with 99.78% genetic similarity to Pantoea ananatis strain MZ007857.1. Sequencing of the gyrB gene showed that the sequence length of PA-1 was 1136bp, with 99.29% genetic similarity to P. ananatis strain MW981331.1. Then, a pathogenicity text was conducted to verify Koch's postulates, which was done by first inoculating P. ananatis into LB liquid medium (shake culture at 28°C, 180 r/min). The log phase cell was collected by centrifugation (5,000 r/min for 2 min at 4°C), and inoculated strains were resuspended in sterile water at OD600 = 0.5. The bacterial suspension was inoculated on healthy cucumber leaves with a syringe. The control was sterile water, which was injected onto healthy cucumber leaves using the same methodology. The plants were placed in a greenhouse with a diurnal temperature difference of 21- 27°C and were observed daily. After two weeks, all bacterial inoculated plants developed symptoms of shriveling and necrosis (Figure 2b), while the control group showed no symptoms. From the symptomatic plants, the pathogen was isolated again and identified by morphological and molecular characterization. The sequences of the isolates recovered from the inoculated experiment matched 100% the sequences of the isolate PA-1. Koch's postulates were completed by following the previously described method. To our knowledge, this is the first report of P. ananatis causing leaf spot of cucumber.

The present study investigated the biological management of root-knot nematode (Meloidogyne incognita) in tomato plants using different strains of Pseudomonas spp. The experiment involved five treatments: a healthy control (T1), a nematode-inoculated control (T2), Pseudomonas fluorescens strain A (T3), P. fluorescens strain B (T4), and P. putida (T5). The results demonstrated significant differences in plant growth and root gall formation across treatments. The healthy control exhibited an average plant height of 12 cm and weight of 11 g. Nematode inoculation slightly reduced growth, with plants averaging 11 cm in height and 10 g in weight. Treatment with P. fluorescens strain A resulted in the highest growth, with plants reaching 13 cm in height and 12 g in weight. P. fluorescens strain B and P. putida treatments produced plants with average heights of 12 cm and 12.5 cm, and weights of 11 g and 10 g, respectively. Leaf and flower counts also varied, with T3, T4, and T5 treatments increasing leaf counts to 26, 40, and 33, respectively, compared to 15 in the nematode-inoculated control. The application of P. fluorescens strains A and B significantly reduced root galls to 8 and 15, respectively, compared to 29 in T2. P. putida treatment resulted in 21 root galls. These findings highlight the potential of Pseudomonas spp., especially P. fluorescens strains, in managing nematode infestation in tomato plants. Future studies should explore the mechanisms behind these microbial interactions and their long-term effects on plant health and yield.

The effects of chitosan and sixteen Paenibacillus strains against the wilt pathogen Ralstonia solanacearum were evaluated in vitro and under greenhouse conditions. Chitosan and two Paenibacillus strains, in particular Paenibacillus polymyxa MB02-1007, were found to have strong in vitro antibacterial activities against R. solanacearum. In addition, chitosan applied as soil drench or seed treatment significantly reduced wilt incidence by 72% and 48%, respectively while P. polymyxa MB02-1007 as a soil drench or a seed treatment significantly reduced wilt incidence by 82% and 88%. In general, regardless of the application method, plant growth parameters as well as the activities of chitinase and b-1,3- glucanase in tomato plants were significantly increased by chitosan and P. polymyxa MB02-1007 as compared to the corresponding control, both in the absence and presence of R. solanacearum. The growth of tomatoes, however, was promoted by chitosan more as a soil drench than as a seed treatment, while P. polymyxa MB02-1007 as a seed treatment was more effective than as a soil drench. This is the first report on the use of chitosan for the control of tomato wilt and promotion of tomato plants. In conclusion, both chitosan and P. polymyxa MB02-1007 show promise for plant growth promotion and control of R. solanacearum in tomato. Combining chitosan and P. polymyxa may improve disease control, which should be examined in future studies.

In Queensland Vertisols, several crops, including linseed (Linum usitatissimum L.), have been affected by 'long fallow disorder' This was a serious nutritional disorder causing poor growth of crop plants over large areas of wheat-growing land in Queensland. The disorder was linked to a decline in the number of viable propagules of VAM fungi during a weed-free fallow period, leading to poor colonisation of the roots of subsequent crops. Linseed was clearly very dependent on VAM for P and Zn nutrition; its yield when grown in sterilised soil without added nutrients being increased 100-fold by the addition of some VAM spores. Changes in the soils' VAM population could therefore influence its apparent P or Zn deficiency. It was hypothesised that soil chemical analysis alone might not reliably predict the P and Zn status of a crop grown in that particular soil. For this thesis, a series of glasshouse experiments were designed to determine the response of linseed to jointly varying rates of P, Zn and mycorrhizal inoculimi. Rates of P ranged from 0 to 800 mg kg-1 of soil, Zn ranged from 0 to 60 mg kg-1 and VAM inoculum was applied as Glomus mosseae spores firstly at two rates (presence or absence of spores) and then at rates of 0, 1, 3, 8, 25 and 75 spores g-1 Plants were grown in pots in a Vertisol that was partially sterilised by steaming at 70°C for 30 min. The results confirmed the very high mycorrhizal dependency of linseed, which decreased as applied P increased. Without mycorrhiza, linseed required extremely high, uneconomic additions of P and Zn to achieve full growth potential (400 mg P and 15 mg Zn kg-1). With mycorrhiza, good growth was achieved with no added P and just 3.75 mg Zn kg-1, and maximum growth with 200 mg P and 7.5 mg Zn kg-1 Eight spores g-1 of soil gave colonisation levels adequate to supply the plant with nutrients without causing growth or yield penalties compared to higher levels of VAM inoculum. At an average level of P and Zn in soil (50 mg P and 7.5 mg Zn kg-1), high levels of spores in the soil (up to 75 spores g-1) led to faster growth of the linseed plant due to faster colonisation of the roots (shorter colonisation lag phase) and better P and Zn nutrition earlier in the growth of the plant. Dry weight data was successfully modelled using levels of P and Zn, and VAM inoculum level in a multiple Mitscherlich approach. Several forms of the model were tested, initially fitting data for -VAM and +VAM plants separately and then using a model that included levels of VAM inoculum. The model allows prediction of potential responses or savings in P and Zn due to mycorrhizal colonisation by solving the equation for given circumstances (P and Zn status, expected VAM levels). Significant savings in P and Zn fertiliser can be made by the presence of high levels of mycorrhizal colonisation in the crop roots, illustrating the benefit of a mycorrhizal over a non-mycorrhizal cropping system. In the process of culturing VAM spores for the use in pot experiments in this study, maize host plants became infected with the pathogen Pythium myriotylum. We assessed the effects of anti-oomycete fungicides (metalaxyl as 0.05% Ridomil® 250 WP (100 mL/pot as a soil drench) or 2.5 g Ridomil® 50 G /10 L of soil, fosetyl-Al as 0.1% Aliette 740WP (200 mL/pot as a soil drench) and phosphonic acid as o.25% Foli-R-Fos 400 (100 mL/pot as a soil drench)) on colonisation of maize by strains of Glomus mosseae, G. macrocarpum, G. etunicatum and G. microcarpum. The fosetyl-Al and phosphonic acid treatments were phytotoxic to the maize and total length of mycorrhizal root was markedly decreased. Metalaxyl had no phytotoxic effects on the maize and did not adversely affect mycorrhizal colonisation. Metalaxyl was consequently routinely incorporated into our open pot cultures of VAM fungi on maize.

Abstract. Husna, Tuheteru FD, Arif A. 2021. Arbuscular mycorrhizal fungi to enhance the growth of tropical endangered species Pterocarpus indicus and Pericopsis mooniana in post gold mine field in Southeast Sulawesi, Indonesia. Biodiversitas 22: 3844-3853. Gold mining activities contribute to the national economy, but have a serious impact on forest and environmental degradation and pose a threat to tree species in the tropics. Reforestation of post-gold mining with tropical legume tree species is threatened with extinction. Arbuscular mycorrhizal fungi are effective in conservation of endangered plants and restoration of degraded land. The objective of the study was to evaluate the effect of native AM Fungi inoculation on the growth of Pterocarpus indicus and Pericopsis mooniana in nurseries and post-gold mining fields. P. indicus and P. mooniana seedlings were inoculated with Glomus claroideum Schenk & Smith, Glomus coronatum Giovann., and mixed AMF (G. claroideum, G. coronatum). Uninoculated seedlings were used as control treatment, and they were maintained for 4 months under greenhouse conditions. After 4 months in greenhouse, seedlings were transferred to post-gold mine and planted for 4 months. The percentage of AMF colonization, plant growth, nutrient content and uptake of N, P, K, Fe, Mn were measured after 4 months both in the greenhouse and the field. The percentage of AMF colonization under greenhouse conditions in P. indicus and P. mooniana ranged 5.67-75.3% and 2.2-41.2%. All AMF colonization tended to have higher shoot height, leaf numbers and nodules, plant dry weight and N, P, K content under greenhouse conditions. Shoot height, stem diameter, leaf dry weight, N, P, K, Mn and Fe under field conditions had higher inoculated seedlings than control four months after planting. AMF could be used to conserve endangered tree species in post-gold mining reforestation in the tropics.

Endophytes have a symbiotic relationship with plants and play an important role in supporting the plant growth. The objective of this study was to examine the effect of endophytic bacteria isolated from citrus leaves on promoting seedling growth and influencing some biochemical attributes in brinjal (Solanum melongena L.). Isolated bacteria were characterized based on molecular tool 16S rRNA. The bacterial isolates were identified as Enterococcus faecalis, Brevibacillus borstelensis, Staphylococcus haemolyticus, Bacillus safensis, B. megaterium, B. cereus, Pseudomonas sp., P. aeruginosa, Enterobacter hermachei and Proteus mirabilis based on 16S rRNA sequence homology and phylogenetic analysis. The leaves of brinjal seedlings were inoculated with these bacterial endophytes by injection method under greenhouse conditions. About one month after inoculation, the plants were analysed for their physical (shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight and root dry weight,), bio-physical (chlorophyll a and b contents, and relative leaf water content), and biochemical (total phenolic, flavonoids and carotenoids contents) parameters. In the present study, Bacillus safensis and Pseudomonas sp. significantly increased the shoot length, shoot fresh and dry weights, relative leaf water content, leaf chlorophyll b content, phenolics and flavonoids in brinjal plants after the application of the bacterial inoculum. However, carotenoids content remained unaffected by the bacterial inoculum. Thus, some bacterial endophytes possess prospective potential in improving plant growth and could be used as inoculants to establish a sustainable crop production system.

Biological control agents (BCAs) from different microbial taxa are increasingly used to control bacterial wilt caused by Ralstonia solanacearum. However, a quantitative research synthesis has not been conducted on the role of BCAs in disease suppression. Therefore, the present study aimed to meta-analyze the impacts of BCAs on both Ralstonia wilt disease suppression and plant (host) growth promotion. The analysis showed that the extent of disease suppression by BCAs varied widely among studies, with effect size (log response ratio) ranging from −2.84 to 2.13. The disease incidence and severity were significantly decreased on average by 53.7% and 49.3%, respectively. BCAs inoculation also significantly increased fresh and dry weight by 34.4% and 36.1%, respectively on average. Also, BCAs inoculation significantly increased plant yield by 66%. Mean effect sizes for genus Pseudomonas sp. as BCAs were higher than for genus Bacillus spp. Among antagonists tested, P. fluorescens, P. putida, B. cereus, B. subtilis and B. amyloliquefaciens were found to be more effective in general for disease reduction. Across studies, highest disease control was found for P. fluorescens, annual plants, co-inoculation with more than one BCA, soil drench and greenhouse condition were found to be essential in understanding plant responses to R. solanacearum. Our results suggest that more efforts should be devoted to harnessing the potential beneficial effects of these antagonists, not just for plant growth promoting traits but also in mode of applications, BCAs formulations and their field studies should be considered in the future for R. solanacearum wilt disease suppression.

Plant-beneficial Pseudomonas spp. can promote plant growth by a wealth of mechanisms. Developing microbial inoculants encompassing multiple Pseudomonas strains (consortia) could represent an attractive solution to some of the problems encountered by single-strain inoculants, such as inconsistent rhizosphere colonization under field conditions. In this study, we evaluated the potential of Pseudomonas protegens B21-024 and Pseudomonas putida B21-029, inoculated alone or in combination, to promote lettuce growth under greenhouse and representative commercial field conditions. Plant growth metrics, including shoot fresh and dry weights, were used to evaluate plant growth promotion. In addition, unmanned aerial vehicle imaging was used to monitor plant growth in the field. Strain-specific primer-probe sets were also developed to study, using the quantitative polymerase chain reaction, the population dynamics of the two strains in rhizosphere soil. P. putida B21-029 and the Pseudomonas consortium significantly increased lettuce shoot fresh/dry weight under greenhouse conditions. In the field, only inoculation with P. protegens B21-024 and the Pseudomonas consortium promoted lettuce growth by significantly increasing shoot dry weight. Interestingly, the nitrogen-rich bacterial growth medium used to prepare the inocula played a role in the plant growth promotion achieved. Overall, the rhizosphere population of both Pseudomonas strains remained relatively stable during the growing season. However, the population of P. protegens B21-024 was significantly higher when it was co-inoculated with P. putida B21-029 than when inoculated alone, suggesting the existence of a beneficial relationship. These findings support the use of Pseudomonas consortia to promote the growth of leafy greens under field conditions.IMPORTANCESome bacteria belonging to the genus Pseudomonas can establish mutually beneficial relationships with many crop species, resulting in disease suppression and/or plant growth promotion. These microorganisms show potential to replace, at least in part, synthetic fertilizers and pesticides in agricultural field settings. While some Pseudomonas strains have been shown to promote lettuce growth, successfully developing Pseudomonas consortia would have many advantages over single-strain inoculations, including better effectiveness and rhizosphere colonization. In this study, a consortium encompassing two Pseudomonas strains successfully promoted lettuce growth under greenhouse and field conditions. The nitrogen-rich bacterial growth medium used for the preparation of inocula contributed to the plant growth promotion achieved. Strain-specific molecular markers were also developed to monitor the abundance of each strain in rhizosphere soil throughout the growing season. The results obtained in this study indicate that the two Pseudomonas strains under study successfully colonized the lettuce rhizosphere.

The plant growth was influenced by plant genetic and growth environment. In a homogeneous growth environment, the difference variables plant growth caused by plant genetic differences. Early growth of the plants will produce good production. In the field, the vegetative growth performance of mangosteen and related species seedling is not yet well defined. The research which aim to find rootstock vegetative growth performance of mangosteen and three related species seedling, was conducted in Indonesian Tropical Fruit Research Institute, Solok from June 2012-August 2013. Four spesies Garcinia which consist of mangosteen and three related species G. porrecta, G. celebica, and G. redia were arranged in randomized block design and five replications. The results showed that there were different performance of mangosteen and three related species at growth variables i.e. plant height, leaf length, leaf width, number of leaf, leaf area per strand, leaf area, specific leaf weight, stem diameter, number of branch, canopy diameter, plant dry weight, shoot dry weight, root dry weight, shoot/root ratio, bast dry weight, and leaf dry weight. In generally, G. porrecta was the most rapid growth at 12 months than the other species, while G. celebica was the slowest growth than the other species. G. porrecta could be used as rootstock candidate at 12 months. Keywords : Mangosteen, genetic character, vegetative growth

The suitability of by-products from the cotton ginning industry for incorporation into growth media for three vegetable crops was examined. Composts were prepared by mixing the by-product with soil in 5 ratios (20:80, 40:60, 60:40, 80:20, 100:0, v/v compost and soil). Seeds of lettuce (Lactuca sativa L.), radish (Raphanus sativus L.) and spinach (Spinacia oleraceae L.) were sown directly within the composts and in 100% peat (control) in October (autumn crop) and December (winter crop). Plant growth (height, leaf number, dry and fresh weight, chlorophyll content) was recorded 19 and 17 days after transplantation (first and second sowing respectively) and at harvest. Fresh and dry weight was recorded at harvest. Overall, plant height and leaf number were higher when the growth media consisted principally of compost (higher ratios of cotton by-product: soil) than in the control (peat), whereas among the various ratios of compost: soil significant differences were recorded, media with a high compost content showing better growth in most cases. Similar results were reported for fresh and dry weight and chlorophyll content, except for dry weight in the second sowing, where growth media with a lower compost content had a higher dry weight. In conclusion, the incorporation of the cotton ginning by-product into compost resulted in better growth of lettuce, spinach and radish, suggesting that the use of this material may be of economical value as a spin-off product for the cotton ginning plant and also as a means of reducing present pollution of the environment due to the accumulation of waste material.