مجله زیست فناوری گیاهان زراعی
پیاپی 36 (زمستان 1400)

MicroRNAs are main groups of small, non-coding molecules that regulate gene expression in animals and plants. Ajwain (Trachyspermum ammi) is plants known for their medicinal properties. To date, no miRNAs have beenidentified in T. ammi. Therefore, in the present study, a computational approach based on homology search through Blastx algorithm against mirbase database was used to predict miRNA and their target genes. The parameters of GC percentage, minimum folding free energy, minimum folding free energy index and secondary structure were determined and the sequences of miRNA precursor candidate were identified. In order to investigate the expression of selected genes using Real time PCR, an experiment was performed in a completely randomized design on the ajwain Arak ecotype at three levels of 0, 12 and 24 hours after methyl jasmonate application. A total of nine miRNAs including miR156, miR160, miR166, miR168, miR171, miR172, miR396, miR477 and miR827 were identified. It was estimated that they regulate 931 of T. ammi genes, which belong to several gene families with different biological functions. Jasmonate and its derivatives are plant signaling molecules. Therefore, miR160 and miR166 expression was evaluated by Real time PCR technique. The results showed that pri-miR160 and pri-miR166 was up-regulated in response to methyl jasmonate treatment, that indicated pri-miR160 and pri-miR166 were associated with hormone transfer.

Calcineurin B-like proteins (CBLs) are a subfamily of calcium sensors that play a role in various plant cell processes and molecular functions. In sesame (Sesamum indicum), in silico analysis of the CBL gene family was performed to identify CBL proteins involved in calcium signaling. Using their orthologic relationships with Arabidopsis homolog genes, the nine SiCBL genes were identified and subdivided into six groups: SiCBL1, SiCBL2, SiCBL3, SiCBL4, SiCBL8, SiCBL10. The molecular weight of SiCBL proteins ranged from 24.4 to 37.9 kDa, the Isoelectric acid pH range, the instability index ranged from 33.99 to 47.46 percent, the aliphatic index ranged from 80.29 to 10.89, and the GRAVY ranged from -0.420 to 0.061. Prediction of post-translational modifications revealed that palmitoylation motif was observed in all siCBL, however majority of them did not have myristoylaton motif. In term of gene structure, 11% of SiCBL genes had nine exons, 11% had eight exons and 77% had seven exons. The RNA-seq pattern of the SiCBL subfamily under PEG treatment revealed that, whereas members of this gene family had generally similar expression patterns in both susceptible and tolerant cultivars, due to functional Convergence, each member of this gene family had a distinct expression pattern. Future research on the expression of SiCBL and SiCIPK gene family genes under various abiotic conditions could aid in understanding the mechanism of expression control of SOS-related genes.

Maize is the third most important cereal after wheat and rice in the world and is a major seed source for many people in Africa, Latin America and Asia. Knowledge on function and extent of genes effect is one of the necessities to achieve high yielding cultivars. In this regard, molecular marker technology has eliminated the need to know the pedigree of genotypes for estimating the kinship matrix to evaluate genotypes breeding values. In this research, 97 genotypes of maize were evaluated in a randomized complete block design (RCBD) with 6 replications for agronomical traits. In the molecular experiment, the molecular profiles of the genotypes were prepared with 28 pairs of Inter-retro transposon amplified polymorphism (IRAP) and Retro transposon-microsatellite amplified polymorphism )REMAP( primers. Estimation the breeding valueofstudied traits in maize genotypes was done through the best linear unbiased prediction (BLUP) in the mixed linear model framewo rk by integrating molecular data based calculated kinship matrix. Considering the sum of estimated breeding values ranks for the studied traits, genotypes P3L11, P10L9, P9L6, P19L5 Kahia and (Paternal) OH43 / 1042 had the highest ranks. Positive breeding value shows that these genotypes have the greatest potential in transmitting the value of traits to the next generation. Genotype P14L2 with positive and high breeding value for leaf length, leaf area, cob weight and leaf area index and P16L6 Kahia with positive and high breeding value for plant height to cob height, cob length and grain weight in the plant, can be introduced as desirable parents to improve these traits in maize breeding programs.

Improvement of the root architecture lead to higher grain yield and seed quality. This is achieved via improvement of the plant growth, better establishment in soil, higher absorption of water and nutrition resulting in the biosynthesis of the essential amino acids and hormones. It increases the efficiency of the nutrition usage and the stress tolerance. Drought conditions are a serious challenge in Iran; therefore, improving crop tolerance has a major importance. In this study, we investigate the presence of DRO1 gene, which is involved in the modification of the root growth angle, in rice cultivar Hashemi and compared to the Kinandang Patong cultivar. We further analyze the simultaneous presence of DRO1 and a second gene, OsCKX4, which is involved in the improvement of root structure. DRO1 and OsCKX4 are cloned together in a single construct under the control of the ubiquitin and the root specific promoters, respectively. The resulting construct, pUhrCkDro is transformed into the Agrobacterium tumefactions strain EHA105 and used for the gene transformation into Hashemi cultivar. Putative transgenic plants, survived on 50 mg. L−1 Hygromycin during tissue culture steps, are transplanted into the Yoshida solution and then into the pots until they set seeds. Construct specific and gene specific PCR analysis are used to confirm the transgenic plants. Transgenic plants show stronger root structure compared to the non-transgenic ones. Molecular analysis in the T1 and T2 generations leads to the homozygous events. The multi-genic construct used in this study, can be introduced into other crops for the aim of root structure improvement and drought tolerance. It is hoped that the production of transgenic rice with enhanced root structure results in improving drought tolerance, reducing water consumption and enhancing yield under drought stress conditions.

Abiotic stress and callus formation can increase total phenolic content and antioxidant activity. The aim of this study was to increase the amount of total phenol and antioxidant activity in Securigera securidaca L. and its calli by ultrasonic stress in vitro conditions. The plants were grown in the greenhouse. Callus formation was performed with MS culture medium containing α-naphthalene acetic acid (2.2 mg/L) and 6-Benzylaminopurine (8.8 mg/L). Ultrasonic stress was applied to the main plants for 10, 20 and 30 minutes in 15 days in vitro conditions; in addition, the ultrasonic stress was applied to the calli for 10 minutes at the same time. The samples were collected on the first, fifth, tenth and fifteenth days. The samples were then dried in an oven, then their ethanolic extract was prepared. Total phenol content and antioxidant activity tests were performed by Folin-Ciocalteu and Wu methods respectively on the leaves of the main plant and its calli. The results showed that the amount of total phenol in the 30 minutes on the first day of ultrasonic treatment is higher than the control. In all treatments, antioxidant activity was reduced compared to the control sample. The highest amount of phenol was observed in calli in ultrasonic stress treatment on the 15th day. Antioxidant activity was reduced in calli under ultrasonic stress compared to the control sample. Therefore, it can be concluded that ultrasonic stress in the samples of this experiment increased the amount of phenolic but did not affect the antioxidant activity. Callus formation and ultrasonic stress also increase total phenol content simultaneously.

Abiotic stresses, especially water deficit stress in plants, cause oxidative stress and as a result, they produce reactive oxygen species (ROS) and cause serious damage to the DNA, protein and internal structure of plants. Plants have enzymatic and non-enzymatic defense mechanisms and systems to deal with these stresses. Currently due to climate changes, Water deficit stress is one of the problems of agricultural production. Given the importance of molecular studies and molecular and enzymatic responses of plants under abiotic stress conditions, therefore, relative expression of catalase and DREB-2 genes were studied by RT-PCR and catalase enzymatic activity were studied in SC706 and SC260 genotypes. The experiment was performed as a split plot based on a randomized complete block design with three replications and three irrigation conditions of (normal irrigation, intermediate stress and severe water deficit stress) under field condition. Results of relative expression analysis of genes showed a significant difference between the treatments so that by increasing the intensity of water stress compared to normal irrigation, the amount of enzyme activity and relative expression of the studied genes were increased. Under severe and intermediate water deficit stress, compared to normal irrigation, DREB-2 gene showed the highest increase with 690 and 211% respectively. In this study, based on the activity of catalase enzyme and the expression of CAT genes, DREB2 of SC706 genotype had higher performance than SC260, more appropriate physiological-molecular behavior and more expression of genes, which indicates more tolerance of SC706 genotype than SC260. The stress conditions applied in this study are the results that can be used in molecular breeding programs of maize.

The root system architecture and the related traits are important factors for moisture uptake from deep soils. Information on QTLs controlling rice root system architecture was collected from the related papers and databases. A genome-wide meta-analysis was conducted on the QTLs using data from 28 independent QTL mapping studies in 38 different rice populations. Among the 312 QTL regions that were mapped on the reference genetic map, 84 and 228 QTL regions were identified under normal moisture conditions and drought stress, respectively. After projection and displaying the QTLs on the reference consensus map, the meta-QTL analysis was performed using BioMercator software version 4.2. A total of 69 significant MQTLs regions were detected on the 12 rice chromosomes. The identified meta-QTL regions included 5-32 initial QTLs and reflecting multiple QTLs for 3-5 traits associated with root architecture. After evaluating the confidence intervals and the number of initial QTLs for each meta-QTL region, 23 meta-QTL regions were selected as the most important ones and the genes located in the MQTL regions were identified. WRKY, ARF, IAA, EXPA, WOX, HOX, YUCCA, RHL and NAC were among the important candidate genes involved in rice root system architecture, which were located in the MQTL regions. Interestingly, 60 MQTLs were co-located with SNP peak positions reported in rice genome-wide association studies (GWAS) for root morphological traits. The promising candidate genes and MQTLs can be used for genetic engineering and MQTL-assisted breeding of root traits to improve yield potential, stability and efficiency in water deficit environments for rice.