Isolasi dan Identifikasi Gen Penyandi Peptida Antimikroba Defensin pada Tanaman Famili Solanaceae

Abstract

Resistensi antibiotik merupakan ancaman kesehatan global yang mendorong pencarian agen antimikroba alternatif. Peptida antimikroba khususnya defensin, memiliki potensi signifikan. Tanaman famili Solanaceae dikenal kaya AMP, namun eksplorasi gen penyandi defensin pada spesies lokal Indonesia masih terbatas. Penelitian ini bertujuan mengidentifikasi keberadaan gen penyandi defensin pada lima spesies Solanaceae: terung, takokak, tomat, kentang, dan kecubung. Metode meliputi isolasi DNA (dengan optimasi penggunaan nitrogen cair, konsentrasi CTAB, Proteinase K, dan RNAse), desain dan seleksi primer spesifik (F3-R3 terpilih sebagai yang terbaik berdasarkan panjang basa, Tm, %GC, dan stabilitas struktur), serta amplifikasi PCR dan analisis elektroforesis. Hasil menunjukkan DNA genom berhasil diisolasi dari kelima sampel dengan kualitas cukup berdasarkan nilai kemurnian DNA rasio A260/280 dan A260/230 untuk amplifikasi PCR. Amplifikasi PCR berhasil menghasilkan fragmen DNA berukuran sekitar 250 bp pada semua sampel, meskipun pita DNA yang diperoleh masih tergolong samar. Penelitian ini mengindikasikan potensi adanya gen defensin pada tanaman Solanaceae yang diteliti, namun diperlukan optimasi lanjutan untuk meningkatkan spesifisitas dan kejelasan hasil amplifikasi.

Antibiotic resistance is a global health threat that drives the search for alternative antimicrobial agents. Antimicrobial peptides (AMPs), particularly defensins, possess significant potential. Plants of the Solanaceae family are known to be rich in AMPs; however, the exploration of defensin-encoding genes in local Indonesian species remains limited. This study aimed to identify the presence of defensin-encoding genes in five Solanaceae species: eggplant, turkey berry, tomato, potato, and datura. Methods included DNA isolation (with optimization of liquid nitrogen use, CTAB concentration, Proteinase K, and RNase), specific primer design and selection (F3-R3 selected as the best based on base length, Tm, GC content, and structural stability), as well as PCR amplification and electrophoretic analysis. The results showed that genomic DNA was successfully isolated from all five samples with adequate quality, based on DNA purity values from the ratios A260/280 and A260/230 for PCR amplification. PCR amplification successfully yielded DNA fragments of approximately 250 bp in all samples, although the DNA bands obtained were still relatively faint. This study provides preliminary evidence for the presence of defensin genes in the studied Solanaceae plants, though further optimization is needed to enhance amplification specificity and clarity.