Mustafa Erayman

Genome of wild olive and the evolution of oil biosynthesis

Significance We sequenced the genome and transcriptomes of the wild olive (oleaster). More than 50,000 genes were predicted, and evidence was found for two relatively recent whole-genome duplication events, dated at approximately 28 and 59 Mya. Whole-genome sequencing, as well as gene expression studies, provide further insights into the evolution of oil biosynthesis, and will aid future studies aimed at further increasing the production of olive oil, which is a key ingredient of the healthy Mediterranean diet and has been granted a qualified health claim by the US Food and Drug Administration. Here we present the genome sequence and annotation of the wild olive tree (Olea europaea var. sylvestris), called oleaster, which is considered an ancestor of cultivated olive trees. More than 50,000 protein-coding genes were predicted, a majority of which could be anchored to 23 pseudochromosomes obtained through a newly constructed genetic map. The oleaster genome contains signatures of two Oleaceae lineage-specific paleopolyploidy events, dated at ∼28 and ∼59 Mya. These events contributed to the expansion and neofunctionalization of genes and gene families that play important roles in oil biosynthesis. The functional divergence of oil biosynthesis pathway genes, such as FAD2, SACPD, EAR, and ACPTE, following duplication, has been responsible for the differential accumulation of oleic and linoleic acids produced in olive compared with sesame, a closely related oil crop. Duplicated oleaster FAD2 genes are regulated by an siRNA derived from a transposable element-rich region, leading to suppressed levels of FAD2 gene expression. Additionally, neofunctionalization of members of the SACPD gene family has led to increased expression of SACPD2, 3, 5, and 7, consequently resulting in an increased desaturation of steric acid. Taken together, decreased FAD2 expression and increased SACPD expression likely explain the accumulation of exceptionally high levels of oleic acid in olive. The oleaster genome thus provides important insights into the evolution of oil biosynthesis and will be a valuable resource for oil crop genomics.

Transcriptome analysis of wheat inoculated with Fusarium graminearum

Plants are frequently exposed to microorganisms like fungi, bacteria, and viruses that cause biotic stresses. Fusarium head blight (FHB) is an economically risky wheat disease, which occurs upon Fusarium graminearum (Fg) infection. Moderately susceptible (cv. “Mizrak 98”) and susceptible (cv. “Gun 91”) winter type bread wheat cultivars were subjected to transcriptional profiling after exposure to Fg infection. To examine the early response to the pathogen in wheat, we measured gene expression alterations in mock and pathogen inoculated root crown of moderately susceptible (MS) and susceptible cultivars at 12 hours after inoculation (hai) using 12X135K microarray chip. The transcriptome analyses revealed that out of 39,179 transcripts, 3668 genes in microarray were significantly regulated at least in one time comparison. The majority of differentially regulated transcripts were associated with disease response and the gene expression mechanism. When the cultivars were compared, a number of transcripts and expression alterations varied within the cultivars. Especially membrane related transcripts were detected as differentially expressed. Moreover, diverse transcription factors showed significant fold change values among the cultivars. This study presented new insights to understand the early response of selected cultivars to the Fg at 12 hai. Through the KEGG analysis, we observed that the most altered transcripts were associated with starch and sucrose metabolism and gluconeogenesis pathways.

Evaluation of seedling characteristics of wheat ( Triticum aestivum L.) through canonical correlation analysis

To examine the seedling characteristics of nine different bread wheat (Triticum aestivum L.) varieties, several variables regarding seedling size and germination characteristics were analyzed using canonical correlation analysis. Significantly correlated first canonical variate pairs indicated that the variables within each set such as coleoptile length, shoot length and fresh weight within the size set, and emergence rate index and germination percentage can be regarded as main factors for vigorous wheat seedlings. The variables such as root number, root weight and dry weight did not seem to have predictive power on seedling size measurements of wheat. Both emergence rate index and somewhat germination percentage within the first canonical variate of germination set appeared to be the correct factors for vigorous germination of wheat seed. Our analysis revealed that compared to other variables, coleoptile length and emergence rate index are powerful determinants of reliable germination, and in turn for better wheat stand establishment. Selecting for these traits in early generation is expected to increase the seedling vigor of wheat. Canonical correlation analysis was shown to be suitably sensitive to detect relationships between seedling variables in bread wheat.

Genome-wide identification of salinity responsive HSP70s in common bean

The present study is aimed to identify and characterize HSP70 (PvHSP70) genes in two different common bean cultivars under salt stress. For this purpose various in silico methods such as RNAseq data and qRT-PCR analysis were used. A total of 24 candidate PvHSP70 gene were identified. Except for chromosome 4 and 7, these candidate PvHSP70 genes were distributed on the remaining chromosomes. While the lowest number of PvHSP70 genes was determined on chromosomes 1, 3, 5, 7, 9, 10 and 11 (one HSP70 gene), the highest number of PvHSP70s was on chromosomes 6 and 8 (seven HSP70 genes each). Three genes; PvHSP70-5, -9, and -10 were found to have no-introns. In addition, four tandemly and six segmentally duplicated gene couples were detected. A total of 13 PvHSP70 genes were targeted by miRNAs of 44 plant species and the most targeted genes were PvHSP70-5 and -23. The expression profile of PvHSP70 genes based on publicly available RNA-seq data was identified and salt treated leaf tissue was found to have more gene expression levels compared to the root. qRT-PCR analysis showed that the transcript concentrations of upregulated PvHSP70 genes in leaves of Zulbiye (sensitive) were mostly higher than those of Yakutiye (resistant). The present study revealed that PvHSP70 genes might play an important role in salt stress response for common bean cultivars and variability between cultivars also suggests that these genes could be used as functional markers for salt tolerance in common bean.

Molecular and ecological investigations on the wild populations of Glycyrrhiza L. taxa distributed in the East Mediterranean Area of Turkey

This paper covers studies on the molecular and ecological aspects of G. glabra var. glandulifera, G. flavescens ssp. flavescens and G. echinata collected from Hatay (Turkey); with the aim to better understand their genetic variation and ecological requirements for possible conservation programs. The material including total genomic DNA was extracted by the CTAB, and for PCR reaction, a total of 14 SSR primers developed for Medicago truncatula were used. PCR amplifications were performed in a Multigen® Thermal Cycler. Soil samples were analysed for their texture, pH, total soluble salts, calcium carbonate, total N content, total phosphorus and organic matter content. In order to see the association between genetic, ecological and geographical data, a similarity matrix was generated. Genetic similarity distances between genotypes were correlated with those of Eucledian distances obtained from ecological and geographical data. Analysis of molecular variance (AMOVA) was performed using GenAlEx 6.5 software to determine variation among and within genetic variations. The genetic analysis showed that the highest expected heterozygosity values were obtained from G. glabra while the lowest were obtained from G. echinata. In general heterozygosity values were low, especially for G. echinata. Therefore, variation appears to be lower within each species than among three species. The physical and chemical analysis of soil and plant samples indicates that mineral accumulation in plants is substantially affected by the soil characteristics. There is a need for identification of better strategies for the improvement of varieties, especially for small farmers managing marginal soils. More studies should be conducted in order to safeguard these taxa, especially G. glabra var. glandulifera which is collected intensively due to its economic value, the same is true for endemic taxon G. flavescens ssp. flavescens.