Publication: Zeytin bitkisinde (Olea europea L.) kuraklık stres tolerans mekanizmasının belirlenmesinde karşılaştırmalı transkriptom ve proteom yaklaşımları
Abstract
Kuraklık, özellikle Akdeniz iklim kuşağında yer alan bölgelerde yetiştirilen zeytin bitkisinin (Olea europaea L.) tarımını kısıtlayan en önemli abiyotik stres faktörlerinden biridir. Bu çalışmada, kuraklığa hassas (Gemlik-26) ve kuraklığa toleranslı (Memecik-94) iki farklı zeytin çeşidinde kuraklık stresi ve sonrasında uygulanan iyileşme (recovery) koşullarına karşı gelişen moleküler tepkiler, RNA dizileme (RNA-Seq) yöntemi ile transkriptom, Sıvı Kromatografisi-Tandem Kütle Spektrometresi (LC-MS/ MS) yöntemi kullanılarak proteom düzeyinde bütüncül bir yaklaşımla incelenmiştir. Transkriptomik analiz sonuçları, sekiz transkriptin (pinin-like, beta-amyrin 28-oxidase-like, phospholipase D alpha 1-like, probable glutathione peroxidase 8, chalcone synthase J-like, glutamate dehydrogenase B-like, galactinol synthase 2-like ve DEAD-box ATP-dependent RNA helicase 7-like) kuraklık stresine karşı belirgin şekilde farklılaştığını ve potansiyel biyobelirteç adayları olduğunu ortaya koymuştur. Proteomik düzeyde yapılan analizlerde ise üç proteinin (pre-mRNA-processing-splicing factor 8B, glycine-rich RNA-binding protein 2 ve endogenous alpha-amylase/ subtilisin inhibitör) ifade seviyelerinin hem stres hem de iyileşme süreçlerinde anlamlı olarak değiştiği ve kuraklık stresi için biyobelirteç potansiyeline sahip oldukları belirlenmiştir. Ayrıca aquaporin PIP2-1, beta-amyrin 28-oxidase, katalaz, peroksidaz, askorbat peroksidaz ve Cu/ Zn süperoksit dismutaz gibi transkript ve proteinlerin, stres yanıtında adaptif roller üstlendiği saptanmıştır. Çeşitler arası karşılaştırmalı analizler Memecik-94 çeşidinin kuraklık stresi altında daha geniş kapsamlı ve etkili bir moleküler savunma ağını aktive ettiğini; Gemlik-26 çeşidinin ise daha sınırlı ve genellikle koruyucu mekanizmalara dayalı bir adaptif yanıt geliştirdiğini ortaya koymuştur. Bu bulgular, zeytin bitkisinin kuraklığa karşı çeşitlere özgü savunma stratejileri geliştirdiğini ortaya koymakta ve stres toleransına sahip zeytin çeşitlerinin geliştirilmesi amacıyla gerçekleştirilen ıslah programlarında kullanılabilecek potansiyel gen ve protein biyobelirteçlerinin tanımlanmasına olanak sağlayarak zeytin bitkisinde kuraklık toleransının moleküler temellerinin anlaşılmasına önemli katkılar sunmaktadır.
Drought is a major abiotic stress factor limiting olive (Olea europaea L.) cultivation, particularly in Mediterranean climate regions. In this study, molecular responses to drought stress and subsequent recovery conditions were investigated comparatively at transcriptomic and proteomic levels in two olive varieties: drought-sensitive Gemlik-26 and drought-tolerant Memecik-94. Transcriptomic responses were analyzed through RNA sequencing (RNA-Seq), and proteomic changes were examined using Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/ MS). Transcriptomic analysis revealed significant differential expression of eight transcripts (pinin-like, beta-amyrin 28-oxidase-like, phospholipase D alpha 1-like, probable glutathione peroxidase 8, chalcone synthase J-like, glutamate dehydrogenase B-like, galactinol synthase 2-like, and DEAD-box ATP-dependent RNA helicase 7-like), highlighting their potential as biomarkers of drought stress. Proteomic analysis identified three proteins (pre-mRNA-processing-splicing factor 8B, glycine-rich RNA-binding protein 2, and endogenous alpha-amylase/ subtilisin inhibitor) whose expression levels significantly changed during both stress and recovery phases, suggesting their suitability as biomarkers. Furthermore, adaptive roles were confirmed for aquaporin PIP2-1, beta-amyrin 28-oxidase, catalase, peroxidase, ascorbate peroxidase, and Cu/ Zn superoxide dismutase. Comparative analysis indicated that the drought-tolerant Memecik-94 variety activated a broader and more effective molecular defense network, whereas Gemlik-26 developed a more limited response primarily reliant on protective mechanisms. These findings demonstrate that olive varieties employ cultivar-specific defense strategies against drought, contributing significantly to the understanding of the molecular basis of drought tolerance. The identification of potential genetic and protein biomarkers provides valuable insights for breeding programs aimed at developing drought-tolerant olive varieties.
Drought is a major abiotic stress factor limiting olive (Olea europaea L.) cultivation, particularly in Mediterranean climate regions. In this study, molecular responses to drought stress and subsequent recovery conditions were investigated comparatively at transcriptomic and proteomic levels in two olive varieties: drought-sensitive Gemlik-26 and drought-tolerant Memecik-94. Transcriptomic responses were analyzed through RNA sequencing (RNA-Seq), and proteomic changes were examined using Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/ MS). Transcriptomic analysis revealed significant differential expression of eight transcripts (pinin-like, beta-amyrin 28-oxidase-like, phospholipase D alpha 1-like, probable glutathione peroxidase 8, chalcone synthase J-like, glutamate dehydrogenase B-like, galactinol synthase 2-like, and DEAD-box ATP-dependent RNA helicase 7-like), highlighting their potential as biomarkers of drought stress. Proteomic analysis identified three proteins (pre-mRNA-processing-splicing factor 8B, glycine-rich RNA-binding protein 2, and endogenous alpha-amylase/ subtilisin inhibitor) whose expression levels significantly changed during both stress and recovery phases, suggesting their suitability as biomarkers. Furthermore, adaptive roles were confirmed for aquaporin PIP2-1, beta-amyrin 28-oxidase, catalase, peroxidase, ascorbate peroxidase, and Cu/ Zn superoxide dismutase. Comparative analysis indicated that the drought-tolerant Memecik-94 variety activated a broader and more effective molecular defense network, whereas Gemlik-26 developed a more limited response primarily reliant on protective mechanisms. These findings demonstrate that olive varieties employ cultivar-specific defense strategies against drought, contributing significantly to the understanding of the molecular basis of drought tolerance. The identification of potential genetic and protein biomarkers provides valuable insights for breeding programs aimed at developing drought-tolerant olive varieties.