Postharvest physiology
Soheila Aghaei Dargiri; Davood Samsampour; Majid Askari Seyahooei; Abdolnabi Bagheri
Abstract
Introduction: Tomato (Solanum lycopersicum L.) is a common vegetable that is widely cultivated and consumed worldwide in the Solanaceae family (global tomato production is estimated at approximately 182 million tons in 2017). Tomato, because of its elevated nutritional value, is the second most common ...
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Introduction: Tomato (Solanum lycopersicum L.) is a common vegetable that is widely cultivated and consumed worldwide in the Solanaceae family (global tomato production is estimated at approximately 182 million tons in 2017). Tomato, because of its elevated nutritional value, is the second most common vegetable commodity in the world after potatoes. As with other crops, the global production of tomatoes is threatened by certain biological stresses (such as pests, plant diseases and weeds) and non-biological stresses (such as salinity, drought, floods, cold and heat stress). Nowadays, the excessive use of chemical fertilizers in tomato production in order to increase yields, has resulted in environmental pollution and dangers on the health of consumers. The reaction of cultivated plants to these challenges is indicated by numerous morphological, physiological, biochemical and molecular changes, leading to a direct and indirect decrease in plant growth and productivity. Salinity as a non-biological stress can cause osmotic or ionic imbalance in plant cells. Salinity stress also limits growth and germination by affecting water and reducing water availability and affects crop production. Endophytes represent an eco-friendly option for the promotion of plant growth and for serving as sustainable resources of novel bioactive natural products. One of the alternative ways to restore normal plant growth under salinity stress may be to use plant growth to stimulate endophytes. Endophytes can play an important role in plant survival under salinity stress by reducing the adverse effects of sodium ion. Therefore, this work provides strong evidence that endophyte halophyte can be beneficial for tomato that help tolerate the plants stress. Materials and Methods: The main aim of this study was to investigate the role of endophytic bacteria (Exigubacterium aurantiacum), isolated from Salsola imbricate, in improving the growth of Solanum lycopersicum L. (8320) under salinity stress. The salinity tolerance potential of bacterial endophytes was investigated in vitro. The bacterial was cultured in Nutrient Agar with different concentrations of NaCl (1, 2 and 3 M) and its growth dynamics were investigated after 24 and 120 hours. To prepare the bacterial suspension for inoculation with tomato seeds, the bacteria were cultured on NB (Nutrient Broth) medium for 24 hours in an incubator at 28±1 °C at 130 rpm. The OD suspension was adjusted to a concentration of 1×108 ml. Tomato seeds (cultivar 8320) were washed with ethanol (70%) for 30 seconds and then sterilized with 0.5% sodium hypochlorite for 90 minutes and then completely distilled three times with distilled water. They were autoclaved and washed. For better contact of seeds with bacteria, 1% carboxymethylcellulose was used and then the seeds inoculated with bacterial treatments were placed on a shaker for six hours. Seeds inoculated with bacterial endophytes were planted in seedlings and then placed in pots containing autoclaved soil in the greenhouse of the Faculty of Agriculture, Hormoz University. The experiment was arranged in a factorial experiment based on randomized complete block design with three replications. Experimental treatments included five levels of salinity stress (0, 4, 6, 8 and 10 dS/m-1) and bacterial endophyte inoculation (E. aurantiacum). Analysis of variance of traits was performed using SAS software version 9.4 and the means were compared using LSD method with a probability level of p < /em> Results and Discussion: Analysis of variance showed that among treatments there is significant difference on growth parameters of tomato seedling (p < /em> 0.01), this indicate the positive impact of the bacterial endophyte on the growth parameters of tomato seedling is inoculated with the bacterial than the control plants. In this experiment, stem height, dry weight of stem, leaf and root, percentage of electrolyte leakage, chlorophyll a, chlorophyll b, carotenoid, proline and carbohydrate content were examined. The results of mean comparison showed that salinity stress significantly reduced stem height, stem dry weight, leaves and roots, chlorophyll a, chlorophyll b, carotenoids and increased electrolyte leakage; however, bacterial endophyte reduced the negative effects of salinity stress on tomatoes. Tomato seedling treated with endophytic bacteria showed higher levels of key osmolytes, total soluble carbohydrates and free proline compared to untreated plants under salinity stress. Conclusion: The results also showed that the use of endophytic bacteria increased the growth of tomatoes in saline soil and water, thereby it can be used as an effective tool for growing salinity-sensitive plants such as tomatoes in saline conditions.
Abdolnabi Bagheri; Hamed Hassanzadeh Khankahdani; Vajihe Ghanbari; Majid Askari Seyahooei; Seyyed Saeid Modarres Najafabadi
Abstract
Introduction: Assessment of genetic diversity in Mango can provide a platform to deepen our knowledge about its genetic background and determine the high quality genotypes for involving in the inbreeding programs. The high observed diversity among native landraces of mango can be used in breeding programs ...
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Introduction: Assessment of genetic diversity in Mango can provide a platform to deepen our knowledge about its genetic background and determine the high quality genotypes for involving in the inbreeding programs. The high observed diversity among native landraces of mango can be used in breeding programs to produce better cultivars and utilization of these cultivars as donor parent to transfer desirable characteristics to high-bearing cultivars. Suitable mango cultivars to prepare rootstock and scion and resistant cultivars against diseases and the high yielding cultivars (with regards to alternate bearing in mango) can be recognized by better understanding of available germplasms. In the past two decades in southern Iran, the process of producing the grafted mango trees via seed culturing and grafting suitable cultivars (What has been registered such as Sindary and Langra and what has not been registered) on the seedlings has been accelerated. Therefore, studying the diversity of mango germplasms in these regions can be a good way to identify and distinguish these genotypes. In the present study, native genotypes of mango from Minab and Rudan counties (Hormozgan Province) were collected, which are mainly produced through seed and over time they have been propagated by vegetative methods based on the quality and taste and their diversity, was evaluated using morphological attributes and molecular markers.
Materials and Methods: In this experiment, we studied genetic and morphological diversity of 39 mango genotypes collected from Minab and Rudan counties (Hormozgan province) using ISSR markers and morphological attributes. Morphological characteristics were assessed using IBPGR descriptor. DNA extraction was done using modified CTAB method. Similarity coefficient of ISSR markers was calculated by Jaccard’s procedure. Polymorphism information content (PIC) was calculated using PIC=2fi(1-fi) formula, where fi was frequency of the amplified bands and 1-fi was frequency of the null bands. In order to analyze morphological data SAS 9.1 software was used and the means were compared using LSD test. In addition, it was prepared a 0 and 1 matrix from morphological data and dendrogram of morphological attributes was designed using Jaccard’s similarity coefficient.
Results and Discussion: The dendrogram inferred from morphological characters grouped all genotypes in eight main clades in which similarity of the dendrogram ranged from 0.12 to 0.83 with mean value of 0.54. The least similarity was observed between Almehtari and Charak, and the most similarity was observed among Moshk, AnaMG, Noghal and HalMG. Analysis of 21 morphological parameters in the studied genotypes demonstrated being of significant differences among these genotypes in terms of morphological attributes (except flower density and inflorescence shape). The ISSR primers produced totally 145 scorable bands that the highest and lowest polymorphism band were observed in MI808 (20 bands) and MI827 (6 bands) primers, respectively. Average of PIC was 0.450. The similarity for ISSR markers ranged from 0.31 to 0.90, in which the least similarity was observed between Majlesi and Charak. However, the highest similarity was observed between Gilasi and KalanMB genotypes. It was observed the differences among same genotypes grown in the various regions. In Rudan region in due to better quality of irrigation water as well as sufficient and proper availability to irrigation water, growth conditions for mango trees is better than Minab region. These differences between Rudan and Minab regions in viewpoint of growth conditions can be reason of morphological diversity among mango similar genotypes in both regions, which it has been caused to incompatibility of morphological and molecular markers. For this reason, the genotypes that are genetically similar to each other may have different morphological differences and/or two homonymous genotypes in two regions have significant genetic differences. For example, Clanfar Baziari genotype, which had high genetic similarity (0.90) with Gilasi genotype, had morphological similarity coefficient equal 0.37 together. However Gilasi genotype collected from Ahmadabad Minab had same ecological similarity with Baziari region. In other instant, genetic similarity coefficient of AnaMG genotype was 0.85 with ShozMD, while in these genotypes had 38% morphological similarity. Correlation coefficient between similarity matrix of ISSR and morphological markers was 0.336 and not significant.
Conclusion: It seems that the observed high diversity among morphological attributes is intrinsically and stemming from mango propagation procedure in which mango genotypes highly diverged due to seed propagation. The high genetic diversity showed by morphological attributes was also corroborated by ISSR markers, indicating low environmentally influence-ability of the attributes.
