Sorgum (Sorghum bicolor L.)’da sülfat taşıyıcı (SULTR) genlerin kuraklık stresi altında ifadelerinin belirlenmesi

Küresel ısınmadan kaynaklanan iklim değişikleri nedeniyle kuraklık, özellikle son 20 yılda tarımsal üretimi kısıtlayan en önemli problem haline gelmiştir. Bitkilerin su yetersizliği şartlarına uyum sağlamalarına imkân sağlayacak mekanizmaların anlaşılması, kuraklık nedeniyle meydana gelen verim kayıplarına çözüm bulunması için oldukça önemlidir. Kükürt ve kükürt içeren bileşikler, bitkilerin kuraklık dâhil pek çok stres koşuluyla mücadele etmesinde çeşitli fonksiyonlara sahiptirler. Arabidopsis thaliana’ da 12 adet sülfat (SO4-2) taşıyıcı (SULTR) gen tanımlanmış olup, bu genler kodladıkları proteinlerin aminoasit dizilerindeki benzerlikler göz önüne alınarak dört gruba ayrılmışlardır. SULTR proteinleri bitkilerde sülfatın topraktan alınmasında ve bitki içerisinde taşınmasında çeşitli görevler üstlenmektedirler. Bu çalışmada sorgum (Sorghum bicolor L.) SULTR genlerinin (SbSULTR) kuraklık şartlarındaki ifadeleri incelenmiştir. Yapılan gen ifade analizleri, kuraklık stresi altında yapraklarda beş, köklerde ise altı SbSULTR geninin ifadesindeki artışa karşın, yapraklarda üç, köklerde ise iki SbSULTR geninin ifadesinin azaldığını göstermiştir. SbSULTR4 geninin yapraklardaki ifadesinde yaklaşık yedi katlık bir artış tespit edilmiştir. Elde edilen sonuçlar, kuraklık koşulları altında SbSULTR genlerinin ifadesinin büyük çoğunlukla arttığına ve sülfür içeren bileşiklerin sorgumun kuraklık ile mücadelesinde görev aldığına işaret etmektedir.

Anahtar Kelimeler:

Sorgum, Kuraklık, SULTR genleri, Gen ifadesi, Sülfat

Expression profiles of sorghum (Sorghum bicolor L.) SULTR genes under drought stress

Due to climate changes arising from global warming, drought has become a major problem restricting agricultural production for the last 20 years. Understanding mechanisms that help plants to get adjusted water deficiency is important to come up with yield loss on account of drought. Sulfur and sulfur-containing compounds have significant roles in plants to fight with several stress conditions including drought. Twelve sulfate transporter (SULTR) genes were initially identified in Arabidopsis thaliana and subdivided into four groups based on their protein sequence similarities. SULTR proteins have various functions in plants including sulfate uptake from soil and transportation of sulfate in plants. Expression profiles of SbSULTR genes in sorghum under drought condition were investigated in this study. Gene expression analyses showed that five SbSULTR genes in leaves and six in roots were up-regulated while three SbSULTR genes in leaves and two genes in roots were down-regulated. Approximately, seven fold up-regulation was detected in SbSULTR4 in leaves. Consequently, results revealed that SULTR genes were mainly up-regulated under drought conditions, and sulfur containing compounds got employed in sorghum to battle drought.

Keywords:

Sorghum, Drought, Sulfate, SULTR genes, Gene expression,

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