Physiological and genetic characterization of salt tolerance in tomato (Lycopersicon esculentum)

Thesis (Master)--Izmir Institute of Technology, Molecular Biology and Genetics, Izmir, 2006Includes bibliographical references (leaves: 59-65)Text in English; Abstract: Turkish and Englishx, 66 leavesPlant growth is limited by different environmental conditions. Salt stress is one of these conditions that affects plant growth. Elimination of salt from the soil is time consuming and very expensive. The most effective way to eliminate salinity effects is to produce salt tolerant crops. Both transgenic applications and molecular marker technology are of importance in producing salt tolerant plants. In this study, responses to salt stress of tomato were studied during the germination and vegetative stages of the life cycle. Inbred Backross Lines (IBLs) from a cross between salt-sensitive L. esculentum and a salt-tolerant L. pimpinellifolium were used for evaluation of salt tolerance during seed germination and QTL mapping. At the end of the germination study, it was observed that the IBLs have some degree of salt tolerance. L. esculentum alleles provided improved total percent germination on salt, however, L. pimpinellifolium alleles provided an improved rate of germination on salt. Thus, different parameters of salt tolerance are controlled by different mechanisms during seed germination. L. pennellii introgression lines (ILs) generated by crossing L. pennellii (LA716) to L. esculentum cv. M82 were used to map antioxidant traits related to salt tolerance at the vegetative stage of tomato. Plants of cultivated tomato (M82) and 32 IL lines were grown in aerated Hoagland solution in the greenhouse. At the seven-true leaf stage salt treatment was started and was achieved with the gradual addition of NaCl to the nutrient solution until 150 mM NaCl was reached. Superoxide dismutase (SOD) and catalase (CAT) activities were measured in the leaf tissues of these plants. Enzyme activities of the ILs were compared with M82 and QTLs associated with SOD and CAT activity under control and salt conditions were mapped

Salt tolerance in Solanum pennellii: antioxidant response and related QTL

<p>Abstract</p> <p>Background</p> <p>Excessive soil salinity is an important problem for agriculture, however, salt tolerance is a complex trait that is not easily bred into plants. Exposure of cultivated tomato to salt stress has been reported to result in increased antioxidant content and activity. Salt tolerance of the related wild species, <it>Solanum pennellii</it>, has also been associated with similar changes in antioxidants. In this work, <it>S. lycopersicum </it>M82, <it>S. pennellii </it>LA716 and a <it>S. pennellii </it>introgression line (IL) population were evaluated for growth and their levels of antioxidant activity (total water-soluble antioxidant activity), major antioxidant compounds (phenolic and flavonoid contents) and antioxidant enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase and peroxidase) under both control and salt stress (150 mM NaCl) conditions. These data were then used to identify quantitative trait loci (QTL) responsible for controlling the antioxidant parameters under both stress and nonstress conditions.</p> <p>Results</p> <p>Under control conditions, cultivated tomato had higher levels of all antioxidants (except superoxide dismutase) than <it>S. pennellii</it>. However, under salt stress, the wild species showed greater induction of all antioxidants except peroxidase. The ILs showed diverse responses to salinity and proved very useful for the identification of QTL. Thus, 125 loci for antioxidant content under control and salt conditions were detected. Eleven of the total antioxidant activity and phenolic content QTL matched loci identified in an independent study using the same population, thereby reinforcing the validity of the loci. In addition, the growth responses of the ILs were evaluated to identify lines with favorable growth and antioxidant profiles.</p> <p>Conclusions</p> <p>Plants have a complex antioxidant response when placed under salt stress. Some loci control antioxidant content under all conditions while others are responsible for antioxidant content only under saline or nonsaline conditions. The localization of QTL for these traits and the identification of lines with specific antioxidant and growth responses may be useful for breeding potentially salt tolerant tomato cultivars having higher antioxidant levels under nonstress and salt stress conditions.</p

Synchronization of Circadian Clock Gene Expression in Arabidopsis and Hyaloperonospora arabidopsidis and its Impact on Host-Pathogen Interactions

Organisms across all kingdoms have an internal circadian clock running in 24h cycles. This clock affects a variety of processes, including innate immunity in plants. However, the role of pathogen circadian clocks had not been extensively explored. We previously showed that light can influence infection of the oomycete Hyaloperonospora arabidopsidis (Hpa, downy mildew disease) on its natural host Arabidopsis thaliana. Here, we identified Hpa orthologs of known circadian clock genes (CCGs) Drosophila TIMELESS (TIM) and Arabidopsis Sensitive to Red Light Reduced 1 (AtSRR1) genes. Expression of both HpaTIM and HpaSRR1 showed a circadian rhythm when Hpa was exposed to constant light. Contrastingly, these two genes were negatively regulated by constant dark exposure. Furthermore, the expression patterns of HpaTIM and HpaSRR1 correlate with those of AtCCA1 and AtLHY, indicating a synchronisation of biological clock genes between the host and the pathogen. In addition, screening mutants of Arabidopsis Clock Regulated Genes (AtCRGs) with three virulent Hpa isolates revealed that mutations in AtCRGs influenced HpaTIM and HpaSRR1 expression and Hpa development, indicating a functional link between the plant biological clock and virulence. Moreover, sporulation of Hpa was reduced by targeting HpaTIM and HpaSRR1 with short synthesized small interfering RNAs, indicating that the pathogen clock is also relevant to virulence. We propose that plant and pathogen clocks are synchronized during infection and that proper regulation of both clocks are genetically necessary for pathogen virulence

Mercimek genomunda rekombinant kendilenmiş hatları kullanarak AFLP and SNP markırlarının haritalanması

Precoz X WA8649041 çaprazlanmasıyla elde edilen mercimek RIL haritalama popülasyonunun 101 bireyi SNP ve AFLP markörler kullanılarak genotiplendirilmiştir. Çalışma sonucunda SNP ve AFLP markörlerinden oluşan, RIL mercimek popülasyonuna ait yüksek çözünürlüklü genetik bağlantı haritasının oluşturulması hedeflenmiştir. RIL popülasyonu ve ebeveynlerinde (Precoz ve WA8649041) Illumina platform sekanslama ile GBS protokolü uygulanarak SNP keşfi yapılmıştır. Sekanslama sonucunda elde edilen 7758 SNP markörden 6688 SNP markörün skorlaması yapılmış ve bu tez çalışmasında bu SNP'lerin ilk 400 tanesi haritalamada kullanılmıştır. Çalışmada 6 adet AFLP kombinasyonundan toplam 194 polimorfik bant elde edilmiş ve haritalamada kullanılmıştır. Precoz X WA8649041 populasyon genomu Joinmap 4.0 programı kullanılarak haritalanmış ve toplam 413 cM uzunluğunda harita elde edilmiştir. Çalışmada uzunlukları 16,9 cM ile 73,8 cM arasında değişen 9 farklı bağlantı grubu elde edilmiştir. Bağlantı gruplarının ortalama uzunluğu 45,9 cM ve bağlantı grubu başına düşen ortalama markör sayısı 37 olarak tespit edilmiştir. Harita üzerinde ortalama markör yoğunluğu her 0.9 cM'da 1 markör olarak saptanmıştır. Skorlanan markörlerden 321 SNP (%77) ve 162 AFLP (%9) markörü bağlantı grupları üzerinde yer almıştır. Bağlantı grubundaki maksimum markör sayısı 77 (LG3), minimum sayı ise 10'dur (LG9). RIL popülasyonu ve ebeveynlerinde SNP ve AFLP markörler kullanılarak oluşturulan genetik bağlantı haritası büyük genoma (~4 Gbp) sahip mercimeğin haritalanması çalışmalarına önemli katkı sağlamıştır. Çalışma sonucunda elde edilen bu harita, mercimek ıslahında marköre dayalı ıslah (MAS) analizlerinde kullanılabilir.One hundred one individuals from RIL mapping population derived from a cross between Precoz X WA8649041 were genotyped by using SNP and AFLP markers. This study aimed to develop high-density genetic linkage map of lentil RIL population composed of SNP and AFLP markers. SNP markers were determined by using Illumina sequencing platform-GBS protocol in RIL population and its parents. As a result of sequencing, 6688 SNP out of 7758 SNP markers were scored and in this thesis study first 400 SNPs were used to make linkage map. In this study, a total of 194 polymorphic band were obtained from 6 AFLP primer combinations and used in mapping. Precoz X WA8649041 population genome was mapped by using Joinmap 4.0 software and covered 413 cM. In this study, 9 different linkage group of which sizes were ranging from 73.8 cM to 16.9 cM were obtained. The mean length of linkage groups were determined as 45.9 and 37 markers were obtained per linkage group. An average marker density of 1 marker per 0.9 cM were provided. Among the scored markers, 321 SNP (77%) and 162 AFLP (9%) markers were able to be mapped on linkage groups. The maximum number of markers in one linkage group was 77 (LG3), the minimum was just 10 (LG9). This map made by using SNP and AFLP markers in RIL populations and its parents can be a reference linkage map for lentil mapping studies which has large genome size (~4 Gbp). The linkage map obtained as a result of this study can be used for marker assisted selection (MAS) analysis in lentil breeding studies

MİLGES Projesi Kapsamında Kurulacak Olan Güneş Enerjisi Santralinin Türkiye Elektrik Sistemine Etkilerinin İncelenmesi

TÜBİTAK destekli MİLGES projesi kapsamında, 10 MW'lık bir güneş enerjisi santrali (GES) kurulacaktır. Bu projede, kurulacak olan GES'in ülkemiz elektrik şebekesine etkileri incelenecektir. GES ülkemiz elektrik üretiminin büyük kısmının sağlandığı Güneydoğu Anadolu Bölgesi'nde kurulacaktır. Bu bölgeden enerji iletiminin çok yüksek miktarda olması zaman zaman sorunlar yaşanmasına sebep olmaktadır. Bu yüzden sisteme eklenecek olan GES, kurulu gücü ülkemiz kapasitesinden çok küçük olmasına rağmen, bu araştırmaya konu olmuştur. Bu çalışma kapsamında bölgenin güneşlenme potansiyeli göz önüne alınarak GES'in yıllık (aylara göre) elektrik enerjisi üretim karakteri çıkarılacaktır. Çıkan karakter uyarınca, TEİAŞ'ın enerji tüketim istatistikleri temel alınarak, yıl boyunca GES'in elektrik üretimine katkısı hem enerji olarak hem de yaklaşık maliyet olarak hesaplanacaktır. Bunun yanı sıra en kötü durum senaryoları ile benzetim çalışmaları yapılacaktır. Son olarak benzer güneşlenme karakteristiğine sahip bölgelere bilgisayar ortamında GES'ler eklenerek Türkiye şebekesinin geleceğine dönük benzetim çalışmaları yapılacaktır. Yapılan çalışmalar ikinci donem tez danışmanı ataması yapılacak bir öğrenci ile devam ettirilecek, ve öğrencinin tez çalışmalarının temelini oluşturacaktır. Sonuçlar bir konferans bildirisi olarak uluslararası düzeyde sunulacaktır

Evaluation of the effects of photovoltaic systems on voltage quality

Because of the governmental incentives, the distributed photovoltaic systems are populating rapidly in Turkish Electric System. This work aims to evaluate the effects of those plants to the electrical system in terms of voltage quality by focusing on the specific example of the solar plant being built under the National Solar Power Plant Development Project (Milli Gunes Enerjisi Santrali Gelistirilmesi Projesi, MILGES). In order to be able to evaluate the effects of the PV system under the most challenging situations in terms of power quality, it is assumed that the solar plant is connected to a substation that also supplies an iron and steel plant with an electric arc furnace (EAF). The EAF system is modeled based on the collected real field data, while PV system parameters are obtained from the project documents

A Strategy to Evaluate Solar Power Generation Capability Based on Historical Data

The rapid population of the distributed PV systems brings concerns about system reliability and voltage quality of the power systems. This paper aims to evaluate the effects of those plants to the voltage quality and system reliability of power systems. The paper develops a statistical analysis method by developing metrics for a photovoltaic power plant located in Ankara, Turkey, using power generation data. The generation data involves all uncertainty associated with weather conditions as well as environmental factors. Therefore, it provides a complete statistical analysis of the feasibility of photovoltaic systems at the considered region, and hence its effects to the voltage quality. The study is conducted using historic data gathered from the photovoltaic system located at the Department of Electrical and Electronics Engineering of Middle East Technical University. To validate the obtained results, reliability and voltage quality of the generation is investigated in simulation environment. The results are assessed using voltage regulation and flicker as considered metrics

Identification of bad solar power generation data Hatali Güneş Enerjisi Üretim Ölçümlerinin Tespit Edilmesi

In this paper, a novel method has been presented for the had data identification of the data recovery process from a solar power measurement data set. Due to failures in solar power measurement logging devices, a long period of solar power generation data might necessary to be recovered. In order to ensure that the recovered data is the correct one, the daily solar generation curve has to be investigated. Due to the high data amount, this control process has to be done automatically. It is observed that the daily solar generation curve is much similar to cosine wave. In this study, the recovered data is compared to reference cosine wave and it is aimed to identify the suspicious data group. In this context, this work is based on the normalized residuals test

Small RNA-based plant protection against diseases

Plant diseases cause significant decreases in yield and quality of crops and consequently pose a very substantial threat to food security. In the continuous search for environmentally friendly crop protection, exploitation of RNA interferance machinery is showing promising results. It is well established that small RNAs (sRNAs) including microRNA (miRNA) and small interfering RNA (siRNA) are involved in the regulation of gene expression via both transcriptional and post-transcriptional RNA silencing. sRNAs from host plants can enter into pathogen cells during invasion and silence pathogen genes. This process has been exploited through Host-Induced Gene Silencing (HIGS), in which plant transgenes that produce sRNAs are engineered to silence pest and pathogen genes. Similarly, exogenously applied sRNAs can enter pest and pathogen cells, either directly or via the hosts, and silence target genes. This process has been exploited in Spray-Induced Gene Silencing (SIGS). Here, we focus on the role of sRNAs and review how they have recently been used against various plant pathogens through HIGS or SIGS-based methods and discuss advantages and drawbacks of these approaches