Iranian Journal of Genetics and Plant Breeding
Volume:6 Issue: 1, Apr 2017

Abiotic stresses such as salinity influence agricultural production. Plants generally respond to stimulus conditions in a complex manner involving many genes and proteins. In the evolution process, halophyte plant Aeluropus littoralis has been proven to have abiotic stress-tolerance capacity. A. littoralis is a salt-resistant halophyte providing a wealthy genetic resource for developing salinity tolerance in crop plants. In the present study, the expression of four candidate ESTs including PKL, 5PTase, NUC-L2 and GLYI genes were analyzed in root and shoot tissues by quantitative Real-Time PCR in multiple time points under 600 mM NaCl stress and recovery conditions . Al5PTase gene showed the highest significant up-regulation in shoot and root tissues. However, a significant down-regulation was found for AlGLY gene in root tissues. Furthermore, we found the unique up-regulations for AlPKL and AlNUC-L2 genes expression magnitudes in root tissues under recovery conditions. These results may provide useful information for further understanding of the role of A. littoralis genes and their regulatory pathways, revealing important genetic resources for crop improvement.

Nucleotide binding site leucine-rich repeats (NBS-LRR) accounting for the main disease resistance proteins play an important role in plant defense against pathogen attack. The current study aimed to identify new NBS-LRR gene members in native types of cucurbit species in Iran. Accordingly, DNAs of melon, cucumber and cantaloupe native types to Iran were identified using three primer pairs. PCR products of the expected size were generated and the obtained DNA was cloned using the pGEM-T. BLASTN algorithms were used to compare the insert sequences with sequences available at the Entrez nucleotide and protein. Phylogenetic analyses were conducted using the MEGA software. The results analysis suggests that cucurbit species native types’ genome contain new NBS_LRR resistance gene analogues against cucurbit pathogens. These resistance gene analogues are composed of genes related to both coiled-coil (CC) and toll-interleukin-receptor homology (TIR) domain containing NBS-LRR R-genes. Phylogenetic analysis of these genes shows that they include NBS-LRRs derived from a recent common ancestor. This study provides an insight into the evolution of NBS-LRR genes in the Cucurbit native type species genomes that are resistance analogues against cucurbit bacterial blight pathogen and tomato mosaic virus.

In this research, the effects of zeatin riboside (0.6, 0.8, 1, 1.2 and 1.4 mg l-1), duration of heat stress of 35 °C (6, 8, 10 and 12 days) and mannitol (0, 10, 20, 30 and 40 mg l-1) on anther culture of four eggplant cultivars were investigated in independent experiments. These experiments were performed according to a factorial arrangement in a randomized complete blocks design layout. The results showed significant interaction effects between the cultivars and treatments. The highest percentage of embryo-derived plantlets (25%) was obtained in cultivar Chantal using 1 mg l-1 zeatin riboside and 8 days of the heat stress. The results also indicated that the use of 10 mg l-1 mannitol had the highest embryo-derived plantlets (66.6%) in cultivar Chantal. In cultivars Hadrian and Faselis, the ploidy levels of all regenerated plants from anther culture (10 and 21 plants, respectively) were determined through flow cytometry and it was found that 60% and 57.1% of the tested plants were haploid, respectively. In cultivars Chantale and Valentina, 30 regenerated plants were selected for determining their ploidy levels and the results showed that 40.2% and 51.5% of the plants were haploid, respectively.

In this study, the effects of floret sterilization with sodium hypochlorite, cold stress, heat shock, 2,4-dichlorophenoxyacetic acid and colchicine treatment on microspore viability and induction of symmetrical nuclei divisions were assessed in six genotypes of sugarcane. The highest microspore viability was observed when florets were sterilized with 3.0% and 3.5% sodium hypochlorite in all genotypes tested. More viable microspores were obtained in the cultures exposed to 4 °C. A sharp decrease was observed in viability at higher temperature pretreatments in all genotypes tested. Microspores with 6-10 nuclei were achieved in cultivars ‘L62-96’ and ‘CP57-614’ (5% and 18%) when cultures were pretreated at 4 °C. The nuclei division was strongly inhibited in the cultures exposed to 33 °C and 37 °C. High frequency of 3-5 nuclei microspores were obtained when 25 and 50 mg l-1 2,4-D were applied in the induction medium. Multinuclear microspores were only observed in cultivars ‘L62-96’ and ‘CP57-614’ (4% and 16%) and in the presence of 25 mg l-1 colchicine, however, its higher level (100 mgl-1) strongly inhibited nuclei division of cultured microspores. Symmetrical nucleus division could be induced in microspores of sugarcane when appropriate genotypes, temperature pretreatment and optimum level of 2,4-D and colchicine were used.

Breeding for QPM ear rot resistant cultivars could offer a reliable environmental and economic control of mycotoxins especially for the resource-poor communities that require inexpensive protein diets. This research aims at evaluating a testcross of QPM inbreds with ear rot resistant cultivars to develop resistant topcrosses with high grain protein quality and yield. Seven QPM inbreds (lines) and two open pollinated ear rot resistant varieties (testers) were crossed in a line × tester method (2 × 7). The 14 F1 topcrosses, 9 parents and 2 commercial hybrids (checks) were evaluated at the Lower Niger River Basin Authority, Oke-Oyi, Nigeria in 2014 and 2015 cropping seasons. The ear rot disease ratings in all topcrosses were low (

Symptomatic grapevine samples were collected from vineyards in Zanjan province to detect Grapevine virus A. Total RNA was extracted from symptomatic leaf samples and subjected to cDNA synthesis using random hexamer primers. Then, a DNA fragment around 800 bp including the complete coat protein (CP) gene was amplified from nine out of 57 samples by polymerase chain reaction (PCR) using specific primers. The infection rate of GAV in vineyards was around 4%, 6%, 2%, and 6% in Zanjan, Abhar, Tarom, and Khoramdareh, respectively. Two DNA fragments corresponding to samples Abhar (p25) and Zanjan (p26), were purified and sequenced. The CP-nucleotide sequence identity between two Iranian isolates was 97.3%. However, sequence identity with previously reported isolates were 76 to 95% and 82 to 98% at the nt and amino acid levels, respectively. CP-based phylogenetic trees showed three main groups (I, II, III) in which p25 (MG977013) and p26 (MG977013) isolates were placed in the group I together with isolates from different geographical regions including Palestine (Israel), Italy, Czech Republic, Jordan, USA and South Africa. To our knowledge, this is the first report of detection and phylogenetic analysis of GVA isolates from Iranian vineyards based on the complete CP gene. Positive selection value was observed on codon 25 indicating the role of this position probably in virus survival and flexibility against evolutionary forces.