Determination of genetic diversity, sinigrin contents, and elicitors-induced enhancement of sinigrin in Nasturtium officinale L.

Authors: SOBIA ZAMAN, KHADIM SHAH, BAKHAT ZAMAN, AZIZ ULLAH SAYAL, SYED TATHEER ALAM NAQVI, MOHAMMAD MAROOF SHAH, JAMSHAID HUSSAIN, AMJAD HASSAN, ARSHAD MEHMOOD ABBASI, RAZA AHMAD

Abstract: Nasturtium officinale L. is a plant of significant medicinal importance. The effect of climatic variations on its genetic makeup and biochemistry has not been studied in Pakistan. Present study was conducted to evaluate genetic diversity and variations in sinigrin contents, an important anticancer metabolite, in the leaves of N. officinal collected from different districts of Pakistan including Muzaffarabad, Chilas, Jaglot, Dir, Swat, Abbottabad, and Haripur. Furthermore, the effects of exogenous abscisic acid (ABA), salicylic acid (SA), and sodium nitroprusside (SNP) on the contents of sinigrin and expression of 2-oxoacid-dependent dioxygenase (GSLOH) gene (TR14312) were also studied. Randomly amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers were used for fingerprinting and determination of genetic relationship. Plant from Dir showed dissimilarity and maximum genetic diversity with those collected from other districts, while plants from Abbottabad were grouped with Haripur, and the plants from Chilas were grouped with Jaglot. The polymorphism information content (PIC) which measures the quality of polymorphism ranged from 0.03 to 0.41. The resolving power (Rp) of markers ranged from 0 to 2.0. A strong and quite linear relationship was observed between the resolving power (Rp) of a primer and its ability to distinguish genotypes. High-performance liquid chromatography was carried out to quantify sinigrin contents. Plant from Dir depicted the highest levels of sinigrin (71.12 μM/g) followed by Muzaffarabad (64.86 μM/g), Abbottabad (56.83 μM/g), and Haripur (58.18 μM/g), while plants from Swat and Chilas showed lower values. The plants exogenously treated with elicitors (ABA, SA, and SNP) accumulated more sinigrin than the control plants, similarly exogenous applications especially ABA also upregulated the expression of a gene involved in glucosinolates synthesis. Our findings revealed that N. officinale growing in different localities exhibited genetic and biochemical diversity, and accumulation of phytochemical was positively affected by the application of exogenous elicitors.

Keywords: Abscisic acid, glucosinolates, genetic diversity, N. officinale, salicylic acid

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