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Crops around the world are facing a diversity of environmental problems, of which high temperatures are proving to be the most serious threat to crops. Polyamine putrescine (Put) acts as a master growth regulator that contributes to optimal plant growth and development and increased stress tolerance. Here, the current study aimed to elucidate how Put functions in regulating chlorophyll (Chl) metabolism, oxidative stress, and antioxidant defense, as well as to characterize the expression of genes related to heat stress in tomato seedlings under such stress. The results revealed that Put treatment significantly attenuates heat-induced damage by promoting biomass production, increasing photosynthetic efficiency, and inhibiting excessive production of oxidative stress markers. Heat stress markedly decreased the Chl content in the tomato leaf and accelerated the leaf yellowing process. However, Put-treated tomato seedlings showed a higher Chl content, which could be associated with the functions of Put in elevating PBGD activity (Chl biosynthesis enzyme) and suppressing the activity of the Chl catabolic enzyme (Chlase and MDCase). Under high-temperature stress, the expression levels of the gene encoding factors involved in Chl biosynthesis and Chl catabolism were significantly down- and upregulated, respectively, and this trend was reversed in Put-treated heat-stressed seedlings. In addition, exogenous application of Put boosted the activity of antioxidant enzymes, along with the levels of expression of their encoding genes, only in plants that were heat stressed. Furthermore, the expression levels of heat-shock-related genes (HSP90, HSP70, and HsfA1) were elevated in Put-treated, high-temperature-stressed tomato seedlings. Taken together, our results indicate that Put treatment significantly increases the heat tolerance of tomato seedlings, by elevating Chl concentrations and suppressing Chl catabolic enzyme activity, modulating endogenous free PA content, increasing antioxidant defense efficiency, and upregulating the expression of heat-shock-related genes.

Wheat is the main staple food in the world, so it is the backbone of food security. Drought not only affects growth and development but also ultimately has a severe impact on the overall productivity of crop plants. Some bacteria are capable of producing exopolysaccharides (EPS) as a survival mechanism, along with other metabolites, which help them survive in stressful conditions. The present study was conducted with the aim of inducing drought stress tolerance in wheat through EPS-producing plant growth-promoting rhizobacteria (PGPR). In this regard, a series of laboratory bioassays were conducted with the aim to isolating, characterizing, and screening the EPS-producing PGPR capable of improving wheat growth under limited water conditions. Thirty rhizobacterial strains (LEW1–LEW30) were isolated from the rhizosphere of wheat. Ten isolates with EPS-producing ability were quantitatively tested for EPS production and IAA production ability. Four of the most efficient EPS-producing strains (LEW3, LEW9, LEW16, and LEW28) were evaluated for their drought tolerance ability along with quantitative production of EPS and IAA under polyethylene glycol (PEG-6000)-induced drought stress. The jar experiment was conducted under gnotobiotic conditions to examine the drought-tolerant wheat genotypes, and two wheat varieties (Johar-16, and Gold-16) were selected for further experiments. The selected varieties were inoculated with EPS-producing rhizobacterial strains and grown under control conditions at different stress levels (0, 2, 4, and 6% PEG-6000). The strain LEW16 showed better results for improving root morphology and seedling growth in both varieties. The maximum increase in germination, growth parameters, percentage, root diameter, root surface area, and root colonization was recorded in Johar-16 by inoculating LEW16 at 6% PEG-6000. Plant growth-promoting traits were tested on the top-performing strains (LEW3, LEW9, and LEW16). Through 16S rRNA sequencing, these strains were identified as Chryseobacterium sp. (LEW3), Acinetobacter sp. (LEW9), and Klebsiella sp. (LEW16), and they showed positive results for phosphorous and zinc solubilization as well as hydrogen cyanide (HCN) production. The partial sequencing results were submitted to the National Center for Biotechnology Information (NCBI) under the accession numbers MW829776, MW829777, and MW829778. These strains are recommended for their evaluation as potential bioinoculants for inducing drought stress tolerance in wheat.

Wheat is an important cereal crop, and its significance is more due to compete for dietary products in the world. Many constraints facing by the wheat crop due to environmental hazardous, biotic, abiotic stress and heavy matters factors, as a result, decrease the yield. Understanding the molecular mechanism related to these factors is significant to figure out genes regulate under specific conditions. Classical breeding using hybridization has been used to increase the yield but not prospered at the desired level. With the development of newly emerging technologies in biological sciences i.e., marker assisted breeding (MAB), QTLs mapping, mutation breeding, proteomics, metabolomics, next-generation sequencing (NGS), RNA_sequencing, transcriptomics, differential expression genes (DEGs), computational resources and genome editing techniques i.e. (CRISPR cas9; Cas13) advances in the field of omics. Application of new breeding technologies develops huge data; considerable development is needed in bioinformatics science to interpret the data. However, combined omics application to address physiological questions linked with genetics is still a challenge. Moreover, viroid discovery opens the new direction for research, economics, and target specification. Comparative genomics important to figure gene of interest processes are further discussed about considering the identification of genes, genomic loci, and biochemical pathways linked with stress resilience in wheat. Furthermore, this review extensively discussed the omics approaches and their effective use. Integrated plant omics technologies have been used viroid genomes associated with CRISPR and CRISPR-associated Cas13a proteins system used for engineering of viroid interference along with high-performance multidimensional phenotyping as a significant limiting factor for increasing stress resistance in wheat.

Improving the chemical and physical properties of saline soils is crucial for the sustainable production of sugar beet and e cient processing of beet sugar. Here, the impacts of the application of treated lter cake on sugar beet bioforti cation under saline soil and sugar losses into molasses during beet sugar processing were evaluated for the rst time. The application of treated lter cake signi cantly reduced K%, Na% and α-amino-N while enhanced sucrose content and quality index of beet root juice.Consequently, sugar loss percentage, sugar loss yield and relative sugar loss yield were reduced, whereas recoverable sugar yield was enhanced. Linear regression analysis revealed that quality index and sugar loss yield were increased, whereas sugar loss percentage and relative sugar loss yield were reduced in response to the reduction of soil Na + content accompanied with increasing Ca 2+ content in the soil increased. The results provide treated lter cake as a promising amendment for saline soils remediation for improving bioforti cation of sugar beet and reducing sugar losses during beet sugar processing.

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Soil salinity is a major environmental stress that adversely impacts the growth, development, productivity and quality of crop species, in particular, in arid and semi-arid regions. Identification of chromosomal regions associated with agronomic traits under salinity stress is crucial for improving salinity tolerance in wheat. GWAS and structure analyses were employed to evaluate 289 elite lines of the Wheat Association Mapping Initiative (WAMI) population under low (LS) and high (HS) salinity conditions using 15,737 SNP markers and seven agronomical traits. Evaluated genotypes responded differently to the different environments in all measured phenotypic traits, highlighting genetic diversity within the WAMI population in response to salt stress. Heritability degree ranged from moderate (37%) to high (88%). GWAS identified 118 and 120 significant associations between SNP markers and seven evaluated phenotypic traits under LS and HS conditions, respectively. Significant association of some markers with more than one phenotypic trait was observed, indicating possible pleiotropic or indirect effects. A high degree of significant linkage disequilibrium (> 52%) was observed among SNP markers on different chromosomes indicating epistatic interaction. The salt stress index (STI) exhibited a positive significant correlation to grain yield per plant (GYP) under both LS and HS conditions (R2 = 0.851–0.856). A linear regression between STI and GYP under HS conditions (GYPs) was identified, suggest that STI is the best tolerance index for predicting high yielding-genotypes. The results present the WAMI population as a valuable source for improving yield potential for salt tolerance in wheat. Furthermore, our findings emphasize that GWAS is a powerful tool in promoting wheat breeding through accurate identification of molecular markers significantly associated with agronomic traits, which is essential for marker-assisted breeding.

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