Pengaruh Cekaman Kekeringan terhadap Level Ekspresi Gen ERF189 sebagai TFs (Transcription Factors) dalam Biosintesis Alkaloid pada Tembakau (Nicotiana tabacum L.)

Eva Yunizar Reza Permana Putri, Prof. Dr. L. Hartanto Nugroho, M.Agr. ; Dr. Wiko Arif Wibowo, S.Si.

2025 | Skripsi | BIOLOGI

Tanaman tembakau (Nicotiana tabacum L.) memiliki kandungan metabolit sekunder golongan senyawa alkaloid berupa nikotin. Salah satu permasalahan dalam budidaya tembakau adalah ancaman abiotik berupa cekaman kekeringan yang dapat berdampak pada sintesis metabolit sekunder, khususnya pada tanaman tembakau yang menghasilkan nikotin. Penelitian ini bertujuan untuk mengevaluasi pengaruh cekaman kekeringan terhadap ekspresi gen ERF189 yang memainkan peran kunci dalam biosintesis nikotin pada tanaman tembakau kultivar ‘Manila’, ‘Bligon’, dan ‘Kemloko 2’. Tahapan penelitian terdiri dari persiapan media tanam; penyemaian biji; perlakuan cekaman kekeringan dengan tingkat kapasitas lapang 100%, 75%, dan 50%; pengamatan dan pengambilan data pertumbuhan tanaman; isolasi materi genetik (RNA); sintesis cDNA; dan qRT-PCR. Parameter yang diamati meliputi data pertumbuhan tanaman dan ekspresi gen ERF189 dan dianalisis menggunakan One-way ANOVA dengan uji Duncan (? = 0.05). Hasil penelitian menunjukkan perlakuan cekaman kekeringan menurunkan kemampuan fisiologis dan anatomis tanaman melalui penurunan diameter batang, tinggi tanaman, dan densitas stomata, meski hasil signifikan hanya pada perlakuan kapasitas lapang 100% pada densitas stomata ketiga kultivar. Ekspresi gen ERF189 menunjukkan adanya peningkatan seiring dengan peningkatan cekaman kekeringan meski tidak signifikan. Hasil penelitian ini diharapkan dapat memberikan kontribusi terhadap pengembangan ilmu pengetahuan serta menjadi referensi terkait ekspresi gen regulator ERF189 dalam biosintesis nikotin sebagai respons fisiologis tanaman tembakau terhadap cekaman kekeringan

Tobacco (Nicotiana tabacum L.) contains secondary metabolites, particularly alkaloid compounds such as nicotine. One of the major challenges in tobacco cultivation is abiotic stress, particularly drought stress, which can affect the synthesis of secondary metabolites, including nicotine. This study aimed to evaluate the effect of drought stress on the expression of the ERF189 gene, which plays a key role in nicotine biosynthesis, in three tobacco cultivars: ‘Manila’, ‘Bligon’, and ‘Kemloko 2’.The research stages included soil media preparation, seed germination, drought stress treatments at field capacity levels of 100%, 75%, and 50%, plant growth observation and data collection, RNA isolation, cDNA synthesis, and qRT-PCR analysis. The parameters observed included plant growth data and ERF189 gene expression levels. Data were analyzed using One-Way ANOVA followed by Duncan's multiple range test (? = 0.05). The results showed that drought stress negatively affected the physiological and anatomical characteristics of the plants, as indicated by reductions in stem diameter, plant height, and stomatal density. However, statistically significant differences were only observed in stomatal density under the 100% field capacity treatment across all three cultivars. The expression of the ERF189 gene tended to increase with higher levels of drought stress, although this increase was not statistically significant. These findings are expected to contribute to the advancement of scientific knowledge and serve as a reference for understanding the regulatory role of ERF189 gene expression in nicotine biosynthesis as a physiological response of tobacco plants to drought stress.

Kata Kunci : alkaloid, ERF189, kekeringan, Nicotiana tabacum L., nikotin