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Superoxide dismutases (SODs) are a group of enzymes that have a crucial role in controlling oxidative stress in plants. Here, we synthesized an environmentally friendly SOD mimic, SODm-123, from L-aspartic acid and manganese oxide. SODm-123 showed similar enzymatic activity to Mn-SOD. To gain insights into the role of SODm-123 in oxidative stress tolerance, a series of experiments were conducted to assess the physiological and molecular responses of tomato plants when treated with SODm-123. The results showed that the levels of O2-• and H2O2 in tomato cells were affected by SODm-123 treatment, indicating that SODm-123 can control oxidative stress like Mn-SOD. The results also exhibited that SODm-123 increased the contents of photosynthetic pigments. However, it was noted that SODm-123 resulted in a reduction in the content of soluble sugar and MDA. These results indicate that SODm-123 promoted the efficiency of photosynthesis by regulating the content of H2O2. To further investigate the role of SODm-123 in controlling oxidative stress, a transcriptome analysis was used to identify differentially expressed genes (DEGs) associated with SODm-123 treatment. The results indicated that SODm-123 treatment resulted in 341 differentially expressed genes (DEGs) in treated tomato leaves at 96 h after treatment. Kyoto encyclopedia of genes and genomes (KEGG) revealed that DEGs were involved in pathways such as photosynthetic pigment biosynthesis, ABC transporters, sugar metabolism, and MAPK signaling, which further confirmed a positive role of SODm-123 in improving stress tolerance in plants. Overall, the results of this study suggest that SODm-123 promotes the growth and development of tomato seedlings and therefore can be used as a potential growth-promoting agent for plants.

Syzygium maire is an endemic tree in New Zealand and classified as critically endangered. The in situ populations of this species are further threatened by the incursion of myrtle rust. The biology...

Although historically a surplus food producer, Bulgarian agriculture has faced a downturn in recent decades. Local legume cultivars have lost favour with farmers and the canning industry, due to their low productivity in comparison with imported ones. Diseases and abiotic stresses are the most important factors limiting the production of edible legumes, costing farmers hundreds of euros in lost revenue each year. The overall objective of our ongoing bean mutation breeding programme was to enrich the gene pool of Phaseolus vulgaris L. and to develop genotypes resistant to Xanthomonas axonopodis pv. phaseoli (Smith) (Xap) and Pseudomonas savastanoi pv. phaseolicola (Burkh.) (Psp) using EMS. An elite line and common cultivar (an heirloom and a snap bean type) in Bulgaria, were selected as parents and the chemical mutagen EMS was used for generating mutations. In total, 1000 seeds were treated and the two generated M1 populations were grown in the field. All M2 mutant plants (1650 from initial line IP564 and 2420 from initial cultivar ‘Mastilen 11b’) were grown in field conditions and a number of phenotypic changes were observed on these mutated plants. They were also screened for Xap disease resistance via leaf artificial inoculation under greenhouse conditions. Individual plant selection was performed for the putatively resistant M2 plants. In the M3 generation these lines were screened using artificial inoculation with Xap and Psp pathogens (leaves and pods) under field conditions. Selected M3–M4 lines with confirmed disease resistance were tested for fresh pod quality. Yield tests were started in M4 and M5 generations and, according to their productivity performance, mutants were advanced to the M6/M7 generation for validation. The expression patterns of genes putatively involved in the resistance reactions towards two races of Psp were determined using qRT-PCR for the specific and reference genes. In conclusion, 50 plants with visible morphological changes and/ or increased tolerance to the two targeted bacterial diseases were selected. A total of 20 advanced mutant bean lines are currently being evaluated for their competitiveness in multiple sites.

A recent study aimed to establish the correlation between instrumental (using Stable Micro System Texture Analyzer) and sensory texture analyses assays in snap bean pods (Phaseolus vulgaris L.). The rupture force correlated significantly and negatively with the sensory traits: parchment layer free, crispness, and stringlessness. Firmness measurements of the raw pods by the texture analyzer indirectly gave enough information to use it as a tool for sensory texture analyses of the processed beans. This could allow breeders to evaluate textural quality of cooked pods in the early stages of the breeding and selection program, thus saving time and costs in doing sensory texture analysis.