مجله زیست فناوری گیاهان زراعی
پیاپی 30 (تابستان 1399)

High concentration of salt in soil and water is one of the major factors limiting crop growth and production worldwide. A factorial experiment based on completely randomized design with two biological and three technical replicates was performed in 2018-2019 to study the ion leakage rate and chanes in relative expression of SOS1, P5CS1 and PMP3-6 genes in the root and leaf of Zea mays L. tolerant and susceptible lines under normal and 8 dS/m salinity conditions using real-time PCR technique after 24-hours and 7-days (as short-time and long-time, respectively) of applying salt stress. The results showed that ion leakage rate at long-time was high in the susceptible line than that of the tolerant line. The highest relative expression of P5CS1 and PMP3-6 genes in 8 dS/m salinity stress was observed in the roots of tolerant line. In contrast, the highest increase in the reltive expression of SOS1 gene was observed in the leaf tissue of susceptible line at short-time. Correlation analysis among the relative expression of studied genes revealed a positive significant correlation (P≤0.05) between P5CS1 and PMP3-6 genes expression. Probabiliy, the high expression of PMP3-6 and P5CS1 genes in the root tissue of the tolerant line in the ealier time post salt stress application is responsible for regulating osmotic pressure and preventing excessive Na+ entry into the plant that results in icreasing the tolerance of plant to salt stress. The results of this study can be useful in Zea mays L. breeding programs for producing salinity tolerant varieties.

Brassinosteroids (BRs) are the plant-specific steroidal hormones that regulate a broad spectrum of plant growth and developmental processes under normal conditions and various biotic, and abiotic stresses. BES1 transcription factors regulate the expression of brassinosteroid-responsive genes. Completion of the grape genome sequencing enabled us to undertake a genome-wide identification of the gene families in this plant. Therefore, we performed a genome-wide investigation of BES genes in grape. The physicochemical properties, phylogeny tree, gene structure, conserved motifs, cis-acting elements, miRNA, and gene chip expression of the grape BES1 transcription factors were analyzed using the bioinformatics tools. The results showed that the grape BES1 transcription factors had seven members, which clustered into three subgroups according to the phylogenetic analysis. Each subgroup was well defined by the conserved motifs, implying that close genetic relationships could be identified among the members of each subgroup. According to the chromosomal locations, 1, 1, 2, 1, 1, and 1 genes were located on chromosomes 2, 4, 10, 15, 18, and 19, respectively. The analysis of cis-acting elements indicated that BES1 genes contained response elements of hormones and abiotic stresses, as well as organ-specific elements. The miRNA target analysis indicated that VvBES1-1, VvBES1-3, and VvBES1-5 contained miRNA target position in grape. Gene chip expression profile analysis revealed that the expression patterns of the grape BES1 genes were different in different organs and developmental stages. The analysis of this gene family would provide some theoretical basis for understanding the evolution and function of the BES1 genes in the grape.

Marker-assisted selection (MAS), a selective method which is not influenced by environmental factors. The success of MAS-based breeding programs depends on the selection and validation of the markers used. In this study, to validate the gene(s) associated with salinity stress And evaluation of allelic diversity of these markers in mutant rice lines, Band pattern of 18 SSR markers on a leaf sample of 14 mutant lines (M9) of rice, along with 2 susceptible controls (IR29 And Sepidrood) and 2 tolerant controls (Nonabokra and Dylmani) in 1398 in Genetics & Agricultural Biotechnology Institute of Tabarestan (GABIT). 11 primers were selected based on band pattern analysis in susceptible / tolerant cultivars. The molecular analysis results showed that OsMAPK4, OsCML11 and OsCPK17 had highest polymorphic information content (PIC). OsMAPK4 and OsCML11 had highest marker index (MI) at a rate of 0.23. The lowest PIC (0.05) and MI (0. 11) was accounted for OsCAX(D). Cluster analysis of molecular data, divided rice genotypes into three distinct groups. However, analysis of Biplot classified the genotypes into four different groups. In this study, 3 genes OsCML11, OsMAPK4 and OsCPK17 were identified on chromosomes 1, 6 and 7 respectively, as the most efficient primers in identifying the genetic diversity between the rice genotypes, Considering that these primers have a very high linkage with salinity resistance genes, can be predicted that 3 lines G1 (M9-P1-7-2-1), G8 (M9-P3-21-1-1) and G9 (M9-P6 -7-1-1) have high tolerance to salinity stress.

Stevia rebaudiana Bertoni is a perennial shrub from the Asteraceae; native of Brazil and Paraguai. This Plant is containing sweet steviosides; rebaudioside and isostevol. This experiment was conducted to study the effects of diverse factors on induction and growth of hairy roots induced by Agrobacterium rhizogenes. The seeds were surface sterilized and then cultured on solid MS medium under 250C and 16:8 h photoperiod. After germination and development of seedlings, the root, stem and leaf explant of three different ages (30, 60 and 90 days) were placed on NYA and LB suspension media. Agrobacterium rhizogenes strains (ATTCC15834, R1000 and C58) and acetosyringone were treated on the plant sample by floating and spray method for 72 hrs at 270C. The incubated explants were treated to remove any bacteria and were transferred to 1/2MS media containing 400 mgl-1 cefotaxime. To optimize the growing media for hairy root induction and growth, 1/2 MS medium was enriched with 3% sucrose and 0.2 mgl-1 Indole-3-butyric acid. The results revealed that all the Agrobacterium strains were effective on hairy root induction from root and leaf explant. The highest hairy root induction was belonged to NYA suspension medium co-cultured with 1/2 MS. Furthermore, for the roots proliferation, 1/2MS medium containing 1/5% sucrose was the selected one. Leaf clone (C2LA) stevia lines obtained from ATCC15834 strain had the highest growth.